In the testes D-aspartate induces testosterone synthesis, but its action in the epididymis is unknown. The effects of in vivo D-aspartate administration in rat epididymis were investigated. The findings show that D-aspartate modulates androgen and oestrogen levels and expression of their receptors by acting on 5α-reductase and P450-aromatase gene expression. Our findings support the role of D-aspartate in the male reproductive system.
Reproduction, Fertility and Development
Volume 28 Number 12 2016
RD14398Interaction of the transforming growth factor-β and Notch signaling pathways in the regulation of granulosa cell proliferation
Do signalling pathways in organisms work independently or dependently? To understand the precise mechanism of cell proliferation in follicular development, we conducted this study and found that synergistic effects of the transforming growth factor (TGF)-β and Notch signalling pathways play an important role in regulating granulosa cell proliferation. The interaction between the TGF-β and Notch signalling pathways found in granulosa cells may also exist in many other types of cells.
RD14348Lactation-induced changes in metabolic status and follicular-fluid metabolomic profile in postpartum dairy cows
Poor fertility in lactating dairy cows is a worldwide phenomenon, which has serious financial implications, particularly in season systems of production. This study characterised lactation-induced differences in the composition of the follicular fluid, which potentially impact negatively on the developing oocyte. These data will contribute to our understanding of the factors affecting fertility and may lead to strategies to address them.
It is difficult to study the mammalian ovary in vitro because it is a complex organ that requires a three-dimensional structure to sustain follicle development and oocyte maturation. This study describes an original perfusion system for the culture of whole ovine ovaries for up to 4 days preserving follicle development and endocrine function. This system provides a relevant model for physiological and toxicological studies.
RD15131Effects of brain-derived neurotrophic factor on oocyte maturation and embryonic development in a rat model of polycystic ovary syndrome
Polycystic ovary syndrome (PCOS) is one of the most common reproductive endocrine disorders. It causes abnormal ovulation and infertility in women. We established a rat PCOS model and demonstrated that appropriate concentrations of brain-derived neurotrophic factor (BDNF) promoted oocyte maturation and embryonic development in this model. Our studies indicate that BDNF may benefit women with PCOS by promoting oocyte developmental capacity and embryonic formation.
RD14290Testicular injection of busulfan for recipient preparation in transplantation of spermatogonial stem cells in mice
Transplantation of spermatogonial stem cells (SSCs) has theoretical and practical significance in discovering the mechanisms underlying spermatogenesis and increasing male reproduction potential. We developed a method to prepare recipients for SSCs transplantation using testicular injections of busulfan. The recipients did not die with this method and normal donor offspring were obtained. This safe method could be adapted for use in other species in the future.
RD15044Steroids affect gene expression, ciliary activity, glucose uptake, progesterone receptor expression and immunoreactive steroidogenic protein expression in equine oviduct explants in vitro
Hormones play a key role during the oestrous cycle and pregnancy of the mare, but little information is available on their influence at the level of the oviduct. We used an in vitro model to establish the effect of hormones on the morphology, functionality and gene expression of the equine oviduct. The findings can be implemented in further studies on embryo–maternal interactions.
RD15100Reproductive hormones affect follicular cells and ooplasm of Stage I and II oocytes in zebrafish
Little is known about the regulation of follicle development at the first stages (I and II) in fish or the potential role of hormones. Reproductive hormones had different effects on the ooplasm (increased presence of endoplasmic reticulum) and the granulosa–theca cell layer (reduced progression of cell cycle) of zebrafish follicles, predominantly at Stage II. These results deliver insights into the follicle development of fish species with an asynchronous mode of reproduction.
RD15093Morphometric analysis and developmental comparison of embryos from carriers with balanced chromosomal rearrangements in preimplantation genetic diagnosis cycles
Embryos from carriers with balanced chromosomal rearrangements show distinct developmental characteristics. This study quantified embryo morphological parameters and demonstrates that morphometric characteristics are correlated with developmental outcomes as well as with chromosomal composition in embryos from carriers with balanced chromosomal rearrangements. Combining morphometric and qualitative assessment may increase the precision of embryo evaluation and contribute to improving the efficiency of preimplantation genetic diagnosis.
RD14423Ovarian suppression in a marsupial following single treatment with a gonadotrophin-releasing hormone agonist in microspheres
A practical female synchronisation strategy for marsupials is needed if artificial insemination using frozen stored spermatozoa or other assisted breeding methods are to be part of conservation breeding programs. This study investigated the potential for Lucrin Depot, a therapeutic drug used to suppress reproductive activity in humans, to regulate the marsupial cycle. The results show that Lucrin Depot suppresses reproductive activity and has the potential to synchronise the recovery of breeding activity in the fat-tailed dunnart.
RD15126Fertilisation of cryopreserved sperm and unfertilised quail ovum by intracytoplasmic sperm injection
Intracytoplasmic sperm injection (ICSI) is a promising tool for the conservation of animal genetic resources, but remains a challenge in birds. In this study we demonstrated that cryopreserved spermatozoa combined with ICSI followed by surrogate eggshell culture can result in fertilisation and embryo development in the quail. This study could provide technical improvements to maintain avian genetic diversity using ICSI.
RD15081Developmental potential of 2n/3n mixoploid mouse embryos produced by fusion of individual second polar bodies and blastomeres of 2-cell embryos
Incorporation of a second polar body (PB2) with a blastomeres is considered as a causal mechanism of human 2n/3n mixoploidy. Using a mouse model, we produced 2n/3n mixoploid embryos to demonstrate their developmental competence. These embryos will be useful for understanding the production mechanism of human 2n/3n mixoploidy.
RD14449Freezability of Andalusian donkey (Equus asinus) spermatozoa: effect of extenders and permeating cryoprotectants
A suitable method for cryopreserving semen is needed for the conservation of endangered donkey breeds. This study compared the effect of two semen extenders and four permeating cryoprotectants on post-thaw sperm quality of Andalusian donkeys. It concluded that Gent B improved in vitro post-thaw sperm quality of donkey spermatozoa, but the replacement of glycerol with 1% ethylene glycol or 2.5% dimethylformamide increased sperm protection against cryodamage.
RD15195Asynchronous embryo transfer as a tool to understand embryo–uterine interaction in cattle: is a large conceptus a good thing?
Embryo–uterine synchrony is critical for the establishment of pregnancy. The aim was to examine the effect of embryo–uterine synchrony on conceptus development and pregnancy in cattle. Results demonstrate the strong regulatory effect of the uterus on conceptus development and the importance of synchrony for optimal pregnancy rates.
RD15119High fructose consumption in pregnancy alters the perinatal environment without increasing metabolic disease in the offspring
Maternal dietary intake is important for a healthy pregnancy but it is not clear whether high intake of sugar, particularly fructose, has long-term adverse effects on the offspring. Mothers fed fructose were fatter, had mild diabetes, and poor vascular control in pregnancy; offspring did not receive fructose after birth and were heavier at 3 months but not different from control offspring at 6 months of age. Raised fructose during pregnancy resulted in poor maternal health but no major detrimental effects in offspring up to 6 months of age.
RD15027Effect of stallion age on the expression of LH and FSH receptors and aromatase P450 in equine male reproductive tissues
Although stallions may reach an age of >20 years, their fertility often starts to decline earlier. This study demonstrates differences in the responsiveness of testicular tissue to LH and FSH between prepubertal and mature stallions. In postpubertal stallions, no further changes occurred with increasing age. Aromatase, a key enzyme for oestrogen synthesis, seems to be of importance for the maintenance of fertility.
RD15184Distribution pattern of cytoplasmic organelles, spindle integrity, oxidative stress, octamer-binding transcription factor 4 (Oct4) expression and developmental potential of oocytes following multiple superovulation
Due to the low success rate and poor ovarian response, female partners of infertile couple are often subjected to repeated superovulation irrespective of the type of infertility. Repeated exposures to supraphysiological levels of hormones raise concerns about the safety of this procedure on the general health of the individual, gamete quality and impact on embryonic development. In the present study, safety of repeated superovulation cycles was investigated by assessing the quality of oocytes and embryos obtained from mice subjected to repeated superovulation with a gap of 7 days between each cycle. Repeated superovulation was found to adversely affect the quality of oocytes as characterized by altered distribution of cytoplasmic organelles, spindle abnormalities, elevated oxidative stress and altered Oct-4 expression which was associated with decrease in the developmental potential of embryos.
Bovine stem cells in the testis are destined to be spermatozoa in nature, but can be reprogrammed into pluripotent stem cells in culture. We describe the development of a new culture system for bovine spermatogonial stem cells that maintains their germ-cell and pluripotent-cell characteristics. This culture system provides a feasible strategy for establishing pluripotent germ-cell lines useful for genetic modification in domestic species and preservation of endangered species.
RD15136Assessment of yellowtail kingfish (Seriola lalandi) as a surrogate host for the production of southern bluefin tuna (Thunnus maccoyii) seed via spermatogonial germ cell transplantation
Germ cell transplantation is an innovative technology for the production of interspecies surrogates, with the aim here of facilitating easy handling, shorter generation time and a more economical management of bluefin tuna broodstock. The present study demonstrated that transplanted southern bluefin tuna testicular germ cells migrate and colonise the gonads of yellowtail kingfish host, but do not further differentiate and proliferate.
RD16028Effects of intracerebroventricular infusions of ghrelin on secretion of follicle-stimulating hormone in peripubertal female sheep
Negative energy balance is the limiting factor for reproduction and coordination of metabolic signals in the brain is critical during female puberty. This research focused on the effects of ghrelin, a modulator of energy balance, on reproductive activity and revealed that it modulates folliculotropin secretion in peripubertal female sheep. Ghrelin belongs to the neuroendocrine network involved in the regulation of reproductive axis activity at the brain level.
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RD15535Sleep restriction in Wistar rats impairs epididymal postnatal development and sperm motility in association with oxidative stress
Sleep alterations are a public health problem worldwide that affect adolescents during puberty because of early school hours and interactive activities. In the present study, sleep restriction during peripuberty in rats affected epididymal postnatal development and sperm motility, in association with oxidative stress and a decrease in the epithelial compartment in the cauda epididymidis. The results of this study suggest a possibility for improving fertility after sleep restriction.
RD16223Effect and possible mechanisms of melatonin treatment on the quality and developmental potential of aged bovine oocytes
This research expands our understanding of the regulators that delay oocyte aging. Treatment of aged oocytes with exogenous melatonin improves oocyte quality, rearranges the cytoskeleton and improves developmental capacity. Melatonin is a good agent for delaying oocyte aging in vitro and preventing poor developmental competence of bovine oocytes in assisted reproductive technologies.
RD16183Induced sub-lethal oxidative damage affects osmotic tolerance and cryosurvival of spermatozoa
If the physiological balance between production and scavenging of reactive oxygen species (ROS) is shifted towards production of ROS this may result in accumulation of cell damage. The aim of this study was to establish whether sub-lethal oxidative damage negatively affects cryosurvival and pre-freeze sperm osmotic tolerance. Generation of defined levels of intracellular ROS can be used for testing strategies designed to counteract oxidative damage.
RD16310Reproductive dysfunction after mercury exposure at low levels: evidence for a role of glutathione peroxidase (GPx) 1 and GPx4 in male rats
Mercury has been identified as a risk factor for declines in sperm quality and infertility in humans. The present study delves further into the mechanisms of action of mercury, showing a role for glutathione peroxidase (GPx) 1 and GPx4 in the reproductive toxicity of mercury. The involvement of the glutathione system highlights this antioxidant system as a potential target of mercury after its accumulation in reproductive organs.
RD16037Ovariectomy increases the phenotypic plasticity of the female prostate epithelium in the Mongolian gerbil (Meriones unguiculatus)
After hormonal deprivation the female gerbil prostate undergoes several morphophysiological changes. This work identified and characterised the cellular heterogeneity of the female prostate epithelium in normal conditions and after ovariectomy. Secretory cells of the female prostate are not morphologically and functionally uniform, presenting a phenotypical plasticity according to the hormonal environment in which they operate.
RD16280Spatiotemporal expression profile of proteases and immunological, angiogenic, hormonal and apoptotic mediators in rat placenta before and during intrauterine trophoblast migration
The current literature does not provide a comprehensive profile of the factors involved in placental development in rats during intrauterine trophoblast migration. In this study we evaluated the gene and/or protein expression of several placental factors during the second half of pregnancy in rats and demonstrated that the expression of proteases and immunological, angiogenic, hormonal and apoptotic mediators is variable and depends on the stage of trophoblast migration. These changes in the expression profile are probably related to alterations in placental morphogenesis and function.
Infusion of the ovine uterus with hyaluronan (HA) during the pre-attachment period changes the expression of some adhesion markers at the embryo–maternal interface, resulting in reduced endometrial receptivity and failure of embryo attachment. In contrast, local inhibition of HA production in the uterus enhances embryo attachment.
RD15537Circulating anti-Müllerian hormone concentrations in relation to age and season in male and female beluga (Delphinapterus leucas)
Anti-Müllerian hormone (AMH) has been proposed as a biomarker of ovarian reserve in women and has been detected in many species; however, this is the first characterisation of AMH in a cetacean. AMH was described in males and females from the year of birth to over 30 years of age during different reproductive seasons, and a decrease in AMH in older animals (>30 years old) was detected. AMH may be of value for reproductive health monitoring of the species and as a biomarker of reproductive senescence in both sexes.
RD16200Non-surgical sterilisation methods may offer a sustainable solution to feral horse (Equus caballus) overpopulation
Culling feral horses is currently met with public criticism, which has created an urgent need to develop new methods of population control. Delivery of a contraceptive agent that causes sterility, without the need for surgery, is currently under investigation. These novel techniques may provide a sustainable and effective alternative for feral horse control.
RD16122A combination of insulin-like growth factor I (IGF-I) and FSH promotes proliferation of prepubertal bovine Sertoli cells isolated and cultured in vitro
Sertoli cells, which support and coordinate developing sperm in the testes, were isolated from 8-week-old Holstein bull calves. A combination of two hormones (IGF-I and FSH) enhanced multiplication of Sertoli cells. We concluded that increased IGF-I concentrations in bull calves fed high-levels of nutrition during early life increases Sertoli cell number, supports testicular development and results in earlier puberty.
RD16190Effects of freezing and activation on membrane quality and DNA damage in Xenopus tropicalis and Xenopus laevis spermatozoa
Xenopus frogs are key organisms for studying basic biology and for modelling human disease. Genetically altered lines of frogs are therefore made, and it is important for animal welfare and cost-effectiveness to store these as frozen spermatozoa. In this study we show that Xenopus sperm cryopreservation damages the DNA and plasma membrane of spermatozoa and start to identify factors affecting damage levels.
RD15553In vivo and in vitro maturation of rabbit oocytes differently affects the gene expression profile, mitochondrial distribution, apoptosis and early embryo development
Understanding the cellular and molecular mechanisms implicated in oocyte competence during rabbit in vivo and in vitro maturation is necessary to improve IVM systems in these species. This study showed for the first time that gene expression profile of in vivo-matured rabbit COCs is different from that of IVM COCs and these changes are clearly accompanied by stage-specific cytoplasmic remodelling of mitochondria, a lower rate of apoptosis of in vivo-matured CCs and better early embryo development, indicating that oocyte quality is compromised during IVM.
RD16269Sperm antioxidant defences decrease during epididymal transit from caput to cauda in parallel with increases in epididymal fluid in the goat (Capra hircus)
The antioxidant defences of epididymal fluid and spermatozoa are modulated from the caput to cauda epididymidis in a region-specific manner in the goat (Capra hircus), and loss of some of the antioxidant enzymes from spermatozoa during their epididymal transit is compensated for through a simultaneous increase in the expression and/or activity of these enzymes in the epididymal fluid of the respective segments.
Reports of the effects of birthweight on testicular development and implication for sperm production in boars are scarce. These effects were investigated in this study. It seems that high birthweight boars have the potential to produce more spermatozoa and semen doses per ejaculate. Hence, the selection of those boars would be predictive of better lifetime productivity in the boar stud.
RD16135Fish oil and wheat-germ oil supplementation restores ovarian function in streptozotocin-diabetic rats
Diabetes has a profound impact on women’s reproductive health. We aimed to investigate the protective effect of fish oil and wheat-germ oil supplementation on ovarian function in streptozotocin-diabetic rats. These natural supplements counteracted oxidative stress and inflammation induced by diabetes and regained ovarian function by increasing FSH, E2, LH and AMH levels and restoring follicle counts.
Several voltage-gated K+ (Kv) channel subunits are expressed in testis, but their contribution to testicular function remains largely unknown. We provide direct evidence of the relevance of Kv6.4 for male fertility since the targeted deletion of this gene in mice disrupted spermiogenesis, resulting in male sterility. This makes Kv6.4 a potentially interesting pharmacological target for the development of non-hormonal male contraceptives.
RD16063Proliferation and apoptosis processes in the seasonal testicular development of the wild Daurian ground squirrel (Citellus dauricus Brandt, 1844)
Male seasonal breeders show synchronised cycles of testicular growth and involution throughout the breeding cycle. The aim of the present study was to elucidate the regulatory role of cell proliferation and apoptosis in this dynamic testicular development. The study demonstrates, for the first time, that both cell proliferation and apoptosis are stimulated during the prehibernation period in wild Daurian ground squirrels. These findings advance our current understanding of the regulatory mechanisms of seasonal reproduction.
RD15524Analysis of in vitro follicle development during the onset of premature ovarian insufficiency in a mouse model
The developmental potential of follicles from a mouse model of premature ovarian insufficiency (POI) was assessed using follicle culture. Although, follicles cultured from 3- and 6-week-old mice had decreased survival compared to Controls, a population of follicles retain the potential of full development in vitro. These results indicate that in vitro follicle culture is a promising method to rescue follicle development after the onset of POI in this model.
Mouse oocyte maturation is a unique asymmetric division and a lot of polarity proteins may play vital roles during this progress. Our study described an evolutionarily conserved polarity protein Discs-large homologue 1 becomes highly polarized by associating with cytoskeleton and lose-of-function of Dlg1 compromises oocyte maturation. It may provide a new theoretic framework for mammalian meiosis research.
RD16238Imprinted and DNA methyltransferase gene expression in the endometrium during the pre- and peri-implantation period in cattle
A comprehensive understanding of biological processes in the endometrium is vital for identifying the key factors required for successful embryo recognition and implantation. The aim of the present study was to compare the expression of imprinted genes and DNA methyltransferases in the endometrium of cyclic and pregnant beef heifers. Results from this investigation provide new evidence that, in addition to their role in fetal and placental development, imprinted genes and DNA methyltransferases may have a role in establishing uterine receptivity.
RD15489Expression of C-type lectin receptors and Toll-like receptors in decidua of patients with unexplained recurrent spontaneous abortion
This study aimed to explore the mechanisms underlying the pathogenesis of unexplained recurrent spontaneous abortion (URSA). The results suggest that the balance between C-type lectin-like receptors and Toll-like receptors (TLRs) was tilted towards a TLR-dominant response in URSA patients, which may disrupt maternal–fetal immune tolerance, resulting in spontaneous abortion.
MicroRNAs (miRNAs) control several reproductive functions, including oocyte maturation, implantation and early embryonic development. We developed a method for accurate miRNA identification in a small sample of bovine blastocysts. Using pools of only 30 embryos, we identified miRNAs that regulate target genes and metabolic pathways that had not been associated with early embryogenesis before, and are potential biomarkers of developmental competence.
RD15514Role of insulin-like growth factor 1 on cross-bred Bos indicus cattle germinal vesicle oocytes exposed to heat shock
Germinal vesicle oocytes are susceptible to heat stress. The present study demonstrated that the physiological IGF-I concentration of 12.5 ng/ml was able to revert the deleterious effects of heat shock on bovine GV oocyte cellular function and ability to became a blastocyst. This thermoprotective role of IGF1 warrants further in vivo IGF1 manipulation to improve dairy cow fertility during summer.
RD15488In vitro oocyte maturation in a medium containing reduced sodium chloride improves the developmental competence of pig oocytes after parthenogenesis and somatic cell nuclear transfer
The quality of oocytes is a crucial factor in the field of reproductive biotechnology. We observed that maturation of pig oocytes in hypotonic medium with reduced NaCl improves the developmental competence of oocytes by affecting the cytoplasmic microenvironment. An oocyte maturation system using a medium with reduced NaCl could potentially improve the efficiency of reproduction in livestock species after further optimisation.
We recently discovered that the male seminal vesicles harbour a novel seminal fluid microbiome (SFM). The present study shows that short-term feeding of a high-fat diet (HFD) changes the bacterial composition of the seminal fluid and fecal microbiomes. HFD-induced SFM alterations might lead to detrimental health consequences in males, their reproductive partners and resulting offspring.
Serum affects lipid metabolism in oocytes and embryos, and cGMP has been shown to affect lipolysis in adipocytes. The present study shows that serum in the maturation medium interferes with lipid metabolism in oocytes and cumulus cells and these effects depend, at least in part, on the cGMP pathway. Evidence of involvement of this pathway in lipolysis in cumulus–oocyte complexes could contribute to the development of better culture systems for the in vitro production of oocytes and embryos with lower lipid accumulation and better cryotolerance.
RD15530Thawing boar semen in the presence of seminal plasma improves motility, modifies subpopulation patterns and reduces chromatin alterations
Seminal plasma could benefit boar semen when added during thawing. This study shows that that the addition of 10% or 50% seminal plasma during post-thawing incubation improved total motility and the motility pattern (motile subpopulations) of spermatozoa. Chromatin changes were almost non-existent for samples from some male boars, both after thawing and during the incubation, but in males susceptible to these sorts of chromatin changes, seminal plasma reduced or abolished them.
RD16124Periconceptional undernutrition affects in utero methyltransferase expression and steroid hormone concentrations in uterine flushings and blood plasma during the peri-implantation period in domestic pigs
A restricted diet applied to females during the peri-conceptional period may have consequences during the peri-implantation period. In this study we examined DNA methyltransferase 1 (DNMT1) and DNMT3a expression in endometrium and myometrium and oestradiol 17β (E2) and progesterone concentrations in the uterus and blood plasma in pigs during the peri-implantation period. Undernutrition during the peri-conceptional period affects maintenance and de novo DNA methylation in the endometrium, de novo DNA methylation in the myometrium and intrauterine E2 concentrations during the peri-implantation period.
RD16205Changes in testicular function proteins and sperm acrosome status in rats treated with valproic acid
The mechanism by which valproic acid (VPA) causes male infertility is not known. In the present study, testicular proteins and acrosome status were investigated in VPA-treated rats. Acrosome reacted spermatozoa and the expression of Ki-67, cholesterol side-chain cleavage enzyme (P450scc) and tyrosine phosphorylated proteins, except for steroidogenic acute regulatory protein, were decreased in VPA-treated rats. These changes to testicular proteins responsible for spermatogenesis result in male infertility after VPA treatment.
RD16163Potential risks to offspring of intrauterine exposure to maternal age-related obstetric complications
Several hypotheses have been proposed to explain the negative effects of delayed motherhood on an offspring’s morbidity later in life, but they are not supported by clinical and epidemiological evidence. In the present study, we show that the negative effects on offspring of delayed motherhood may be induced by embryo or fetal epigenetic DNA reprogramming associated with maternal age-related obstetric complications. This outcome has direct clinical implications for those women wanting to enrol in a fertility preservation program to offset age-related declines in fertility.
RD16056Evidence of proteinuria, but no other characteristics of pre-eclampsia, in relaxin-deficient mice
This paper reports that pregnant mice deficient in relaxin (Rln–/–) did not exhibit characteristics associated with preeclampsia; plasma sFlt-1 concentrations and blood pressure in pregnant Rln–/– mice were no different compared with age-matched wildtype mice. Although there was evidence of proteinuria in older pregnant Rln–/– mice, this was also observed in non-pregnant mice and was not a consequence of pregnancy. Therefore, pregnant Rln–/– mice are not a suitable animal model to study preeclampsia.
RD16007Circumventing the natural, frequent oestrogen waves of the female cheetah (Acinonyx jubatus) using oral progestin (Altrenogest)
We found that cheetahs do not display typical estrous cycles, but rather frequent waves of estrogenic activity every 7 to 10 days. For effective ovulation induction and the most mature oocytes, gonadotropin treatments had to be given at least 3 days after an estrogen peak. Follicular activity can be suppressed by progestin supplementation, thereby providing a way to quiesce the ovary beforehand.
RD15463Beneficial effects of diazepin-quinazolin-amine derivative (BIX-01294) on preimplantation development and molecular characteristics of cloned mouse embryos
Somatic cell nuclear transfer is frequently associated with abnormal epigenetic modifications. The present study investigated the effects of BIX-01294 on cloned mouse preimplantation embryos and the results indicated that BIX-01294 treatment of cloned embryos has beneficial effects in terms of correcting abnormal epigenetic modifications. It will be investigated further whether BIX may affect postimplantation development by correcting epigenetic modifications.
RD15546Expression of macrophage migration inhibitory factor (MIF) in bovine oviducts is higher in the postovulatory phase than during the oestrus and luteal phase
Macrophage migration inhibitory factor (MIF) may be the molecular link between maternal obesity and the quality of early embryos. This study revealed that MIF expression in the oviduct, where mammalian embryos spend their first 3 days, is higher during the postovulatory phase than during oestrus and the luteal phase in heifers. Therefore, oviduct MIF may be essential for producing good-quality embryos.
RD15539Stathmin 1 plays a role in endometrial decidualisation by regulating hypoxia inducible factor-1? and vascular endothelial growth factor during embryo implantation
The aim of this study was to explore the mechanism of action of stathmin 1 (Stmn1), a protein identified by two-dimensional electrophoresis (2-DE) and mass spectrometry (MS) in a previous proteomic analysis, in regulating embryo implantation, a critical process in pregnancy. Stmn1 was found to play a role in decidualisation and embryo implantation by inhibiting the expression of phosphorylated Akt, hypoxia-inducible factor-1α and vascular endothelial growth factor. These findings contribute to a better understanding of the potential role of Stmn1 during embryo implantation.
This review describes the involvement of the sodium pump Na+/K+-ATPase in various aspects of animal reproduction, including critical roles in embryonic development and specific sperm functions. In addition to regulating ion concentrations, Na+/K+-ATPase participates in several cell signalling pathways. Understanding the role of this molecule creates new opportunities to enhance or suppress various aspects of reproductive biology.
RD16031Methylated oligonucleotide (MON)-induced promoter hypermethylation is associated with repression of CDH1 expression and contributes to the migration and invasion of human trophoblast cell lines
Aberrant DNA methylation has been linked to deficiencies in trophoblast motility and invasion in pregnancy complications. We increased trophoblast cell motility and invasiveness through inducing site-specific hypermethylation and repressing gene expression of CDH1 by sense-methylated oligonucleotides (MONs). The results indicate that MON-mediated DNA methylation on the CDH1 promoter may alter gene expression and contribute to trophoblast motility and invasion.
The use of sex-sorted fresh spermatozoa has the potential to yield higher pregnancy rates than sex-sorted frozen spermatozoa. This study sought to characterise the in vitro quality of X and Y sex-sorted bull spermatozoa and identified the need for tailored diluents for fresh sex-sorted spermatozoa to avoid head-to-head agglutination. The use of fresh sex-sorted spermatozoa, when managed correctly, has enormous potential in the dairy industry.
This work demonstrates that it is necessary for progressive sperm motility that flagellar proteins, like ODF1, maintain reduced cysteines after epididymal transit. To determine how oxidative changes in flagellar proteins affect sperm motility, a sulfhydryl blocker was used; sperm progressive motility was abolished without affecting the level of ATP. Incomplete oxidation in flagellar proteins of asthenozoospermic samples was also observed. Inadequate maturation or an unbalanced thiol status leads to non-progressive motility.
RD16104GRIM-19, a gene associated with retinoid-interferon-induced mortality, affects endometrial receptivity and embryo implantation
We present a new hypothesis of the molecular mechanisms responsible for implantation, which could provide an important basis for further understanding of embryo implantation. Our study shows that spontaneous elimination of GRIM-19 is required for endometrial receptivity and the embryo implantation process. Our results demonstrate the involvement of GRIM-19 in the embryo implantation process by regulating adhesion, apoptosis and immune tolerance.
Using a hamster model, we found significant changes in mitochondrial number, structure and function as well as fecundity, ova production and follicular number in aged compared to younger animals. Old hamsters had decreased fertility rates, smaller litters, and decreased numbers of preantral follicles and MII oocytes. In addition, old ova contained large areas of collapsed, non-luminal cytoplasmic lamellae. Finally, old hamster ova contained higher levels of reactive oxygen species, lower mitochondrial membrane potential and decreased mitochondrial numbers, all of which could be contributing to the age-related decline in mammalian fertility rates.
Androgens (male steroids) interact with the key regulator of female reproduction, FSH, but the nature of their interaction is not clear. Examination of mutant androgen-insensitive mice with and without the expression of human transgenic FSH (Tg-FSH) revealed that subfertility in androgen-insensitive mice is rescued by the presence of Tg-FSH. These findings demonstrate that androgens and FSH actions interact in a synergistic manner to maintain optimal female fertility.
RD16061Putrescine supplementation during in vitro maturation of aged mouse oocytes improves the quality of blastocysts
Poor egg quality underlies reproductive aging in mice and in women. Oocyte maturation is a critical stage in determining the quality of eggs and hence embryonic potential. We demonstrated that putrescine supplementation during in vitro maturation of aged mouse oocytes resulted in healthier embryos. Peri-ovulatory putrescine supplementation may be an effective therapy in reproductive aging.
RD16071Stem cell factor promotes in vitro ovarian follicle development in the domestic cat by upregulating c-kit mRNA expression and stimulating the phosphatidylinositol 3-kinase/AKT pathway
Stem cell factor (SCF) and epidermal growth factor (EGF) play key roles in ovarian folliculogenesis. Herein we report that SCF promotes cat follicle growth by upregulating c-kit mRNA expression and AKT phosphorylation. EGF suppresses the stimulating effect of SCF, leading to a downregulation of FSH receptor mRNA expression. The ability to grow premature follicles in vitro could become a pivotal tool for preserving fertility in animal disease models and endangered felids.
RD15391Iloprost supports early development of in vitro-produced porcine embryos through activation of the phosphatidylinositol 3-kinase/AKT signalling pathway
Despite evidence of the presence of PGI2 in mammalian oviducts, its role in development of early embryos is largely unknown. We revealed that supplementation of PGI2 analog enhanced early development of IVP porcine embryos through activation of AKT cascade. These results indicate that iloprost can be a useful IVC supplement for production of IVP early porcine embryos with high quality.
Diabetes mellitus (DM) has been associated with male reproductive impairment but the underlying mechanisms are poorly understood owing to the diversity of factors involved in the disease. In this study we focused on the in vitro effects of high glucose levels, the primary recognised signature of DM, on spermatogenesis. We found that while mouse testicular luminal area was decreased, Sertoli cell number was increased. These findings suggest an impairment of Sertoli cell function in high-glucose conditions that may impact spermatogenesis.
RD16098Sex of co-twin affects the in vitro developmental competence of oocytes derived from 6- to 8-week-old lambs
The effect of birth type (single, twin, triplet) and co-twin sex on in vitro developmental competence of oocytes from 6 to 8-week old lambs significantly increased blastocyst development rates for lambs born with a female co-twin compared with a male co-twin. This indicates a female co-twin enhancement effect on oocyte development. Selection of lambs for embryo production programs based on co-twin sex is warranted.
Spermatozoa maturation is a necessary step for the best success in artificial reproduction. This study focused on the role of calcium ions in the acquisition of testicular sturgeon sperm to be able to swim: our results show that an influx of Ca2+ ions is required for finalisation of this maturation process.
RD15309Maternal food restriction in rats of the F0 generation increases retroperitoneal fat, the number and size of adipocytes and induces periventricular astrogliosis in female F1 and male F2 generations
Transgenerational food restriction and overweightAdverse environmental factors during gestation, such as under- or overnutrition, may predispose individuals to certain diseases later in life by altering their fetal programming. The present study investigated whether prenatal 40% food restriction was able to induce weight, metabolic and neuroimmune disturbances in the next two generations, even if they were normally fed. We showed a transgenerational transmission effect for overweight over two generations, associated with changes in immune and inflammatory patterns, revealing the severe impact of undernutrition over generations.
RD16123Cryptic male choice: experimental evidence of sperm sex ratio and seminal fluid adjustment in relation to coital rate
Mammalian males do not produce equal numbers of X- and Y-chromosome-bearing sperm, but factors influencing the variation are unknown. We show that sperm sex ratios and ejaculate traits vary with mating rate in laboratory mice, and hypothesise that males that mate frequently are usually more attractive, and would be advantaged by producing sons that inherit their attractiveness.
RD15520Temporary undernutrition during early gestation, corpora lutea morphometrics, ovarian progesterone secretion and embryo survival in gilts
This study looked at how off-feed incidents or competition for feed can affect hormonal regulation of luteal function and early pregnancy in pigs. We found no effect of a day’s fasting on LH secretion, but progesterone secretion was reduced and fewer piglets were born at subsequent farrowing. Malnutrition in group-housed sows or in periods of hot weather can potentially reduce ovarian progesterone output and fertility.
RD15357Non-genomic action of vitamin D3 on N-methyl-D-aspartate and kainate receptor-mediated actions in juvenile gonadotrophin-releasing hormone neurons
Vitamin D deficiency has been linked to impaired pubertal development affecting reproductive physiology. The effects of vitamin D3 were investigated on the juvenile gonadotrophin-releasing hormone (GnRH) neuron, a central regulator of the hypothalamic–pituitary–gonadal axis. Exposure to vitamin D3 suppressed the N-methyl-D-aspartate and kainate-mediated responses of juvenile GnRH neurons. We suggest that vitamin D is essential for normal and timely functioning of pubertal development.
RD16077Aquaglyceroporins 3 and 7 in bull spermatozoa: identification, localisation and their relationship with sperm cryotolerance
For the first time the presence and localisation of AQP3 and AQP7 in bull spermatozoa was determined, together with their relationship to sperm cryotolerance. Our findings show that neither the relative amounts nor the localisation of these proteins was altered by cryopreservation procedures. Furthermore, the abundance of AQP7 in fresh semen was found to predict bull sperm cryotolerance.
RD15414Membrane lipid profile of in vitro-produced embryos is affected by vitrification but not by long-term dietary supplementation of polyunsaturated fatty acids for oocyte donor beef heifers
In this study we evaluated the effect of feeding oocyte donor beef heifers with a protected fat enriched in linoleic acid on embryonic developmental rates after IVF, embryo cryotolerance and the membrane lipid composition of fresh and vitrified–warmed embryos. Although embryo yield, cryotolerance and membrane lipid profile were unaffected by dietary supplementation, the membrane lipid profile was affected by the cryopreservation process. Because the lipid ion abundances of fresh and vitrified–warmed embryos were distinct, they can be used as potential markers of post-cryopreservation embryonic survival.
RD15330The effects of sildenafil citrate on feto–placental development and haemodynamics in a rabbit model of intrauterine growth restriction
Current treatments for intrauterine growth restriction are not particularly effective. Sildenafil citrate (SC), a vasodilator and angiogenic molecule, could be an option to enhance conceptus growth. Here we studied, in a rabbit model, whether the administration of SC could improve or ameliorate diet-induced defects in conceptus development and offspring outcome. SC seems to benefit pregnancies complicated by placental insufficiency; however, further research is needed.
RD15483Variation among individual bulls in the distribution of acrosomal tyrosine-phosphorylated proteins in epididymal and ejaculated spermatozoa
A valid biomarker for sperm molecular characterisation was found in Japanese black cattle. The distribution of acrosomal tyrosine-phosphorylated proteins largely differs among individual bulls. The grades of acrosomal freezability and results of AI with cryopreserved spermatozoa can be predicted by assessing the distribution of acrosomal tyrosine-phosphorylated proteins in spermatozoa before cryopreservation.
RD15538Expressions of lipoprotein receptors and cholesterol efflux regulatory proteins during luteolysis in bovine corpus luteum
Progesterone, which is essential for pregnancy in mammals, is synthesised from cholesterol in the corpus luteum (CL). We investigated the involvement of cholesterol uptake receptors and efflux transporters in bovine CL regression (luteolysis), and found that the expression of scavenger receptor B1, a cholesterol uptake receptor, decreased during luteolysis. The decline in cholesterol uptake may reduce progesterone production in the CL during luteolysis.
The effect of cytokines on human male fertility is attracting more attention. In this in vitro study, the effects of TNF-α and its antagonist, etanercept, in ejaculated human spermatozoa were analysed. The negative influence of TNF-α on sperm function and the positive action of etanercept were demonstrated. This data may have clinical relevance for the management of chronic inflammatory diseases related to male reproduction.
The occurrence of intrauterine growth restriction is linked to a plethora of non-communicable disorders during postnatal life. Our study, using a translational swine model, provides evidence that prenatal developmental is strongly modulated by fetal genotype and sex. Such findings stress the necessity for considering ethnicity and sex effects in the study of the developmental origins of adult health and disease.
RD16033Actions of activin A, connective tissue growth factor, hepatocyte growth factor and teratocarcinoma-derived growth factor 1 on the development of the bovine preimplantation embryo
The reproductive tract secretes molecules collectively known as embryokines that regulate embryonic growth and development. In this study we tested four growth factors expressed in the endometrium for actions on the bovine preimplantation embryo. All four molecules affected embryonic development or gene expression and may therefore function in the endometrium as embryokines.
RD15415Temporal regulation of extracellular signal-regulated kinase 1/2 phosphorylation, heat shock protein 70 and activating transcription factor 3 during prostaglandin F-induced luteal regression in pseudopregnant rats following heat stress
High temperatures are correlated with reduced fertility. Ovarian function in pseudopregnant rats was determined in a laboratory setting of repeated heat stress. Heat stress altered the activity of mitogen-activated protein kinases and the expression of heat shock protein 70 and activating transcription factor 3 in the corpus luteum. A deeper understanding of the effects of heat stress on ovarian function will enable better approaches to promote female fecundity and sustainable animal production.
ISG15 mRNA exists in bovine embryo from one cell stage, which is earlier than IFNT mRNA. When the expression of ISG15 was knockdown, the development of blastocyst was negatively affected, , and the expressions of Ets2, IFNT and connexion 43 were inhibited in bovine blastocysts.
RD16026p21-activated kinase 1 activity is required for histone H3 Ser10 phosphorylation and chromatin condensation in mouse oocyte meiosis
Histone H3 phosphorylation is essential for chromatin condensation, which is a prerequisite for accurate chromosome separation in mitosis or meiosis. The present study demonstrates that p21-activated kinase 1 (Pak1) activity is required for histone H3 phosphorylation and consequent chromatin condensation in mouse oocytes upon the resumption of meiotic progression.
RD16020Implantation rates subsequent to the transfer of embryos produced at different phases during double stimulation of poor ovarian responders
Feasibility of luteal phase ovarian stimulation has already be certified in poor ovarian responders. Embryos produced during the luteal phase resulted in higher implantation rates compared with those produced during the follicular phase. Luteal phase ovarian stimulation should be recommended for poor ovarian responders.
Fipronil, an insecticide widely used in agriculture, veterinary medicine and public health, has been listed as a potential endocrine disrupter. The present study showed that fipronil can affect the sperm motility and compromise sperm quality of the animals. The perinatal exposure to fipronil has long-term effects on sperm parameters, and the epididymis can be a target organ.
RD15492Identification of motility-associated progesterone-responsive differentially phosphorylated proteins
Progesterone is a steroid present in the female reproductive tract that aids sperm motility. In the present study we identified human sperm proteins that are modified in response to progesterone and propose a mechanism by which progesterone would aid motility. This information may be useful for the development of drugs to improve sperm motility and contraceptives.
RD15432Prominin-1 glycosylation changes throughout early pregnancy in uterine epithelial cells under the influence of maternal ovarian hormones
The prominin-1 protein has previously been broadly investigated for its potential role in cancer and stem cell biology. This is the first investigation into the role of prominin-1 in early pregnancy. The study localises prominin-1 to the apical region of uterine epithelial cells and shows that maternal ovarian hormones significantly affect the glycosylation and abundance of this protein.
RD15290Anti-Müllerian hormone reduces growth rate without altering follicular survival in isolated caprine preantral follicles cultured in vitro
Investigations into the relationship between FSH and anti-Müllerian hormone (AMH) during in vitro culture of isolated preantral follicles are lacking. The aim of the present study was to evaluate the effect of AMH, with and without FSH, on the in vitro development of isolated caprine follicles. We demonstrated that AMH reduces follicular growth without altering follicular survival. Thus, AMH may play an important role in regulating the growth of caprine preantral follicles.
RD15253Variable duration of reproductive suppression in male coyotes (Canis latrans) treated with a high dose of the gonadotrophin-releasing hormone agonist deslorelin
A unique approach to managing coyote (Canis latrans) depredation is the development of a one-time deliverable chemical sterilant. We hypothesised that exposure to a high dose of a gonadotrophin-releasing hormone (GnRH) agonist would cause prolonged suppression of the reproductive axis. The results of the present study suggest that a plasma concentration of 100 pg mL–1 deslorelin must be maintained and that elevations beyond this threshold are likely to be unimportant.
RD15261Papain and its inhibitor E-64 reduce camelid semen viscosity without impairing sperm function and improve post-thaw motility rates
Sperm freezing has advanced animal breeding and genetics in numerous species but is not successful in alpacas due to the gel-like nature of the semen. This research aimed to reduce the viscosity of alpaca semen without affecting sperm function. The enzyme papain (0.1 mg mL–1 for 20 min at 37°C) followed by the papain inhibitor E-64 (10 µm for 5min at 37°C) eliminated viscosity and aided cryopreservation of alpaca spermatozoa. These findings will help to advance the use of reproductive technologies in camelids.
RD15494Optineurin suppression activates the mediators involved in the terminal effector pathways of human labour and delivery
Preventing spontaneous preterm birth, which is the leading cause of perinatal mortality and morbidity, is one of the most important issues facing perinatal medicine today. In this study, we found that spontaneous labour is associated with an increase in optineurin (OPTN) expression in fetal membranes and the myometrium, where it functions as a negative regulator of prolabour mediators. Elucidating the role of OPTN in labour processes enhances our understanding of the mechanisms that drive preterm birth and could perhaps lead to the development of a clinical therapeutic strategy.
Early development of the equine embryo occurs in the oviduct, and information on the composition of this oviducal environment is very valuable. We identified the proteins in the oviducal fluid of the horse, and proteins that are important for pregnancy were found in higher amounts when an equine embryo was present. These findings provide a solid basis for further studies on embryo–maternal interactions in the horse.
RD15474Sperm function during incubation with oestrus oviductal fluid differs in bulls with different fertility
Prediction of breeding bull fertility is of major economic value to the cattle-breeding industry. We proved that spermatozoa from high-fertile bulls showed a low degree of tyrosine phosphorylation and high degree of capacitation and acrosome reaction upon exposure to oviductal fluid. These findings may help in developing tools for assessing fertility of bulls, once validated in more animals.
RD15336Carnitine-mediated antioxidant enzyme activity and Bcl2 expression involves peroxisome proliferator-activated receptor-γ coactivator-1α in mouse testis
Because carnitine treatment is used in many cases of male infertility, the aim of the present study was to evaluate the mechanism by which carnitine improves spermatogenesis in mice. In the study, carnitine treatment of mice stimulated peroxisome proliferator-activated receptor-γ coactivator-1α expression, which, in turn, regulated steroidogenesis by enhancing expression of Bcl2 and antioxidant enzymes in the testis.
RD15361Oestrogenic action of neonatal tamoxifen on the hypothalamus and reproductive system in female mice
Tamoxifen is widely used in the treatment of breast cancer and can interfere with the reproductive system. The present study showed that tamoxifen administration during the neonatal period has oestrogenic actions on oestrogen-sensitive nuclei in the brain controlling the reproductive axis in female mice. Therefore, tamoxifen may have adverse effects on brain differentiation and reproductive function.
RD15214Prion protein 2 (dublet) gene (PRND): role in ovine semen capacitation, cryopreservation and fertility
The physiological functions of prion and prion-like proteins are overlapped by their pathological features, namely in the invariably fatal neurodegenerative diseases of both humans and animals, such as Kuru, Creutzfeldt-Jakob disease and new variant, bovine spongiform encephalopathy and sheep scrapie. The aim of the present study was to investigate the role of the prion-like Doppel (PRND) protein and different PRND genotypes in the sperm capacitation process, cryoresistance, and fertility potential. Both factors were crucial for sperm capacitation potential, cryoresistance, and embryo production. Thus, an important physiological function of Doppel protein and genotype in male fertility has been demonstrated.
RD15485Short- and long-term outcomes of the absence of protein during bovine blastocyst formation in vitro
Removal of protein from culture medium improves analytical reliability, although bovine embryo development in vitro could be affected. However, protein removal over a 24-h period in culture led to embryos with reduced miscarriage rates without affecting birthweight, gestation length or calf morphology. This finding represents direct access to culture medium as a substrate for non-invasive analysis, leading to potential biomarker discovery without compromising embryonic viability.
RD15440Effect of Single Layer Centrifugation on reactive oxygen species and sperm mitochondrial membrane potential in cooled stallion semen
Stallion spermatozoa lose viability and fertilising capability relatively quickly when cooled; robust spermatozoa can be selected by colloid centrifugation. In the present study, selected spermatozoa were shown to metabolise differently to controls, producing less hydrogen peroxide, which is known to damage spermatozoa. These results indicate that colloid centrifugation could be used to improve the quality of stallion semen for AI.
Cloned concepti on Day 225 of gestation were characterised by lower pregnancy rates, high gestational losses, a distinctive biphasic growth pattern, with early growth restriction followed by accelerated growth and foetal weight on Day 225, and significant morphological changes in placental mass and shape when compared with in vivo-derived pregnancies. Conversely, Day-225 IVF-derived concepti were widely similar to controls.
Prostaglandins induce contraction and relaxation of oviductal smooth muscle, which are essential for transport of gametes and embryo. The present results demonstrate that lysophosphatidic acid significantly stimulated prostaglandin production by cultured isthmic stromal cells. It is suggested that locally produced lysophosphatidic acid contributes to oviductal motility in the isthmus by regulating prostaglandin production in cows.
RD15306Increased frequency of chromosome congression defects and aneuploidy in mouse oocytes cultured at lower temperature
In vitro manipulation of oocytes is a standard procedure used in assisted reproduction. The aim of the present study was to analyse the effect of suboptimal culture temperatures on various aspects of meiotic division, including chromosomal congression and segregation defects. The results revealed that even a small deviation from optimal culture temperature has a marked effect on chromosome congression and aneuploidy.
RD15424Lower dietary n-6:n-3 ratio and high-dose vitamin E supplementation improve sperm morphology and oxidative stress in boars
Dietary PUFA and vitamin E are known to influence sperm morphology and oxidative stress. The effects of dietary n-6 : n-3 and vitamin E on the sperm morphology and oxidative stress in boars were investigated. An n-6 : n-3 ratio of 6 :1 and 400 mg kg–1 vitamin E have beneficial effects on sperm morphology by improving oxidative stress.
RD15430Expression of 17β-hydroxysteroid dehydrogenase and the effects of LH, FSH and prolactin on oestrone and 17β-oestradiol secretion in the endometrium of pigs during early pregnancy and the oestrous cycle
The uterus produces steroids and primary steroidogenic enzymes are expressed in the uterus of pregnant and cyclic pigs. In this study we examined 17β-hydroxysteroid dehydrogenase expression and the effects of LH, FSH and prolactin on oestrone and 17β-oestradiol release in vitro in endometrial explants. We show that LH, FSH and prolactin may regulate oestrogen release by the endometrium.
RD15390Immunolocalisation of aromatase regulators liver kinase B1, phosphorylated AMP-activated protein kinase and cAMP response element-binding protein-regulated transcription co-activators in the human testis
The hormone oestrogen is essential for testis development and its synthesis is dependent on the enzyme aromatase. However, the molecular mechanism of aromatase regulation is still poorly understood. This study describes for the first time the cellular localisation of proteins important for aromatase regulation, which are well known in breast tissue, in the normal testis. This new finding may help develop new therapies for oestrogen-mediated infertility.
RD15378Lonidamine-ethyl ester-mediated remodelling of the Sertoli cell cytoskeleton induces phosphorylation of plakoglobin and promotes its interaction with ?-catenin at the blood–testis barrier
We are in need of safe, effective and affordable male contraceptives. Indazole carboxylic acids such as lonidamine and adjudin disrupt adhesion between Sertoli and germ cells in the rat testis, resulting in infertility. One of the key findings of this study was that lonidamine-ethyl ester also displayed contraceptive effects. Additional studies are required to determine whether indazole carboxylic acids can enter the clinical pipeline
For the first time, a minimal invasive method that allows ovarian tissue collection from sows is described in detail. This method, a transvaginal ultrasound-guided biopsy, is quick, can be performed by one person, and has no major effects on the sow’s reproductive performance. It can be applied on the farm to study effects of housing or nutrition on luteal function.
RD15315Insulin exposure during in vitro bovine oocyte maturation changes blastocyst gene expression and developmental potential
Metabolic imbalance impairs female fertility. We wanted to find out how metabolism affects bovine oocyte quality, and demonstrated that insulin exposure during in vitro oocyte maturation affects embryo development, morphology and gene expression. Even short-term exposure to a metabolic imbalance has lasting effects on embryo development, and this metabolic programming may have consequences later in life.
RD15425Greater sperm complexity in the Australasian old endemic rodents (Tribe: Hydromyini) is associated with increased levels of inter-male sperm competition
Most species of Australasian old endemic rodents have a highly complex sperm head morphology that contains an apical hook together with two ventral processes of variable length and orientation. This study tested whether this variation is a sexually selected trait using relative testes mass as a proxy for the intensity of inter-male sperm competition and controlling for phylogeny. The angle of these processes, but not length, was positively correlated with relative testes mass; its possible functional significance is briefly discussed.
RD15289Effect of spermatozoa motility hyperactivation factors and gamete coincubation duration on in vitro bovine embryo development using flow cytometrically sorted spermatozoa
This study evaluated the effects of sperm motility enhancers, media and different IVF times on embryo development. The sperm motility enhancers caffeine and theophylline improved cleavage and embryo development rates, synthetic oviducal fluid fertilisation medium outperformed M199 fertilisation medium and shortening the oocyte–sperm coincubation time (from 18 to 8 h) resulted in similar overall embryo performance rates. This study provides important information for optimising IVF protocols.
RD15319Fateful triad of reactive oxygen species, mitochondrial dysfunction and lipid accumulation is associated with expression outline of the AMP-activated protein kinase pathway in bovine blastocysts
In vitro-derived bovine embryos frequently exhibit lipid accumulation, mitochondrial dysfunction and enhanced levels of reactive oxygen species. With the aim of unravelling the role of the AMP-activated protein kinase cytalytic subunit 1alpha (AMPKα), the present study identified AMPKα activity and distinct expression patterns of AMPKα-related genes to be correlated with that phenotype. These results prove the important role of AMPKα in embryonic energy metabolism.
RD15367Growth arrest specific 1 (Gas1) and glial cell line-derived neurotrophic factor receptor ?1 (Gfr?1), two mouse oocyte glycosylphosphatidylinositol-anchored proteins, are involved in fertilisation
In addition to oocyte Cd9 tetraspanin, Juno, a glycosylphosphatidylinositol (GIP)-anchored protein, has recently been discovered to be essential to mammalian fertilisation, as a sperm receptor for Izumo1. The present study demonstrates the involvement of another two other oocyte GPI-anchored proteins, namely growth arrest specific 1 (Gas1) and glial cell line-derived neurotrophic factor receptor α1 (Gfrα1), in fertilisation. The results reinforce the implication of several molecules forming probably complexes.
RD15321Detection of cross-sex chimerism in the common marmoset monkey (Callithrix jacchus) in interphase cells using fluorescence in situ hybridisation probes specific for the marmoset X and Y chromosomes
Bone marrow chimerism is a unique and normal feature of Callithrichidae development that originates through shared placental circulation. A new X and Y chromosome-specific fluorescent in situ hybridisation protocol for Callithrix jacchus has been developed and validated to detect and investigate chimerism between male and female littermates. One of the strengths of this method is that it is useful in interphase cells, and allows cell morphology to remain intact to facilitate identification of cell type.
RD15480Obesity causes weight increases in prepubertal and pubertal male offspring and is related to changes in spermatogenesis and sperm production in rats
Obesity, a global problem, adversely affects human health including reproduction. This study investigated whether exposure to an obesogenic environment during prenatal and postnatal periods affects the initiation and progress of spermatogenesis in rats. It is evident that an obese condition decreases counts of spermatids and spermatozoa and serum levels of testosterone and increases the proportion of abnormal spermatozoa, which might reduce reproductive potential.
RD15358Dietary-induced gestational iron deficiency inhibits postnatal tissue iron delivery and postpones the cessation of active nephrogenesis in rats
Gestational iron deficiency can cause developmental programming of adult hypertension, but the critical developmental window during nephrogenesis has not been studied. The present study examined renal development during perinatal iron deficiency in rats and found altered timing of kidney maturation and histological renal adaptations that may contribute to dysfunctional glomeruli and renal hyperfiltration, which themselves contribute to hypertension.
Finding novel biomarkers of ovarian follicle function would be of benefit. This study investigated the follicle biomarker potential of microRNAs (miRNAs) and found that levels of miR-873 and miR-202 can be used as indicators of steroidogenic capacity in cattle. These miRNAs, in addition or alternatively to commonly used steroid level measurements, could be used to accurately classify follicles based on steroidogenic capacity.
Information about follicle density is critical to determine the quantity of fragments during biopsy procedures in women and domestic animals. This study evaluated the effects of age and determined the minimum number of ovarian fragments and histological sections required to estimate equine follicle density in ovarian biopsy fragments. The results show that follicle density is negatively influenced by increasing age and, independent of follicle heterogeneity, three to four ovarian fragments combined with 65 histological sections are required to accurately determine follicle density in equine ovarian tissue.
RD15356Glucocorticoid-induced changes in glucocorticoid receptor mRNA and protein expression in the human placenta as a potential factor for altering fetal growth and development
Glucocorticoids (GCs) sustain life and the development of human embryo; however, fetoplacental exposure to high maternal GC levels may lead to placental and fetal abnormalities, with the adverse consequences of GC excess manifested later in life. The mechanisms through which GC excess alters placental and fetal development are yet to be identified; however, changes in placental GR levels and subcellular localization and ratios may modify placental function, in utero growth of the fetus and lifelong health.
The average age for a primipara has been increased and maternal age affects the quality of oocytes. The present study addressed whether age-associated deterioration of oocytes stems from the oocyte itself or the surrounding environment and found that follicular fluid plays a major role. On the basis of the results, given optimum conditions, oocytes derived from aged females could give rise to high-quality oocytes.
RD15334Effects of prepartum oilseed supplements on subclinical endometritis, pro- and anti-inflammatory cytokine transcripts in endometrial cells and postpartum ovarian function in dairy cows
Dietary fats are known to influence immune cell function and fertility. The effects of pre-calving diets containing oilseeds (sunflower or canola vs. no oilseed) on uterine inflammation and ovarian function in dairy cows were investigated. Adding sunflower seed to pre-calving diets positively influenced ovarian function without affecting uterine inflammation, suggesting a role for omega-6 fatty acids in nutritional management of reproduction.
Monozygotic (MZ) twins are of great interest to elucidate the contributions of pre- and postnatal environmental factors on the expression of complex traits and diseases. In this study we investigated variations in sperm DNA methylation between MZ twin bulls to understand the observed differences in offspring productivity of MZ twin bulls despite their identical genetic backgrounds. Variation in sperm DNA methylation between MZ twin bulls was observed and may contribute to incongruous diverging performances of daughters sired by these bulls.
RD15230Mammalian target of rapamycin/eukaryotic initiation factor 4F pathway regulates follicle growth and development of theca cells in mice
Follicular growth is mediated by gonadotropic hormones, growth factors and signalling pathways, such as the mammalian target of rapamycin (mTOR) signalling pathway. However, the molecular mechanisms underlying the development of theca cells have rarely been studied. Herein we provide unbiased, detailed and convincing evidence (microarray, in vitro and in vivo studies) to demonstrate that mTOR/eukaryotic initiation factor 4F signalling plays an important role in follicular growth, particularly the development of thecal cells.
RD15406LIM kinase activity is required for microtubule organising centre positioning in mouse oocyte meiosis
In female meiosis, accurate chromosome separation is driven by the spindle apparatus, which is organised under the regulation of unique microtubule organising centres (MTOCs). LIM kinase 1 activity is required for the establishment and maintenance of MTOC bipolarity in mouse oocytes during meiotic division. The results of the present study provide an insight into the molecular mechanism governing bipolar spindle formation in oocytes during meiotic maturation.
RD15243Active 3ʹ–5ʹ cyclic nucleotide phosphodiesterases are present in detergent-resistant membranes of mural granulosa cells
Lipids rafts are specialised membrane microdomains involved in cell signalling and phosphodiesterases are key enzymes involved in cyclic AMP signalling in the ovary. We found that in mural granulosa cell membranes, the cyclic AMP–phosphodiesterase activity is mainly contributed by the rafts. These results suggest that in mural granulosa cells, lipid rafts exist as a cell-signalling platform.
The aquaporin family plays a fundamental role in water and solute transport across biological membranes. The present work has studied, for the first time, the presence and localisation of aquaglyceroporin 3 in boar spermatozoa. Although two different localisation patterns for this protein were identified, neither AQP3 content nor its localisation were found to be correlated with sperm quality parameters.
To determine whether body weight has an effect on semen quality, the present study explored the possible association between body weight (in terms of body mass index) and sperm function. The results indicate that both morbid obesity and being underweight have a negative effect on sperm quality, probably as a result of changes to epididymal function. These findings highlight the importance of an adequate body weight as the best option for fertility.
RD15349Elimination of methylation marks at lysines 4 and 9 of histone 3 (H3K4 and H3K9) of spermatozoa alters offspring phenotype
The function of epigenetic marks present in retained histones of mature spermatozoa is largely unknown. By reducing the methylation level at lysines 4 and 9 of histone 3 of mature spermatozoa we aimed to shed light on their significance during development. We discovered that these marks are important for normal embryo development and their reduction leads to abortions, premature death and morphological abnormalities in the offspring.
We studied for the first time the effect of high inbreeding levels in cattle sperm by automatised and objective methods. An extensive genetic analysis using an animal model showed that inbred bulls have a reduced field fertility and an increased calving interval compared with non-inbred bulls. Sperm from high inbred animals showed an increased ‘hyper-active like’ movement that could explain their decreased fertility.
RD15350In vitro maturation affects chromosome segregation, spindle morphology and acetylation of lysine 16 on histone H4 in horse oocytes
Mammalian eggs are often affected by aneuploidy, leading to failure in embryo implantation, miscarriages and genetic diseases. In horse oocytes the onset of aneuploidy is correlated with the disruption of an epigenetic mark that occurs without changes in gene expression. A deeper knowledge of the molecular basis of aneuploidy will allow the development of safer treatments to obtain healthy eggs.
Infertility affects 1 in 10 couples or millions of people worldwide and while IVF is an important intervention, 75% of all embryos transferred into the uterus do not establish a pregnancy. We investigated how the uterus of infertile women may prevent pregnancy and discovered a protein released by uterine tissue that potentially blocks pregnancy. Targeting this protein may be useful as a new treatment option for infertile women.
RD15159Cumulus cell-conditioned medium supports embryonic stem cell differentiation to germ cell-like cells
The effect of cumulus cell-conditioned medium (CCM) on the differentiation of buffalo embryonic stem cells to germ cells were explored. A concentration of 20%–40% conditioned medium induced the highest expression of primordial germ cell, meiotic, spermatocyte and oocyte markers and led to the formation of oocyte-like structures. Further development of the cumulus conditioned medium induced differentiation strategy would be useful for understanding mammalian gametogenesis and transgenic animal production.
RD15157Is the association between insulin resistance and diabetogenic haematopoietically expressed homeobox (HHEX) polymorphism (rs1111875) affected by polycystic ovary syndrome status?
Insulin resistance (IR) is an underlying factor, common to both polycystic ovary syndrome (PCOS) and type 2 diabetes. Genetic factors have also been reported to play a role in the pathogenesis of these two conditions, indicting a common genetic aetiology. In this study we aim to determine whether the genetic association between IR and diabetogenic SNPs is affected by PCOS status in Iranian women and found that the association may be influenced by the condition.
RD15182Follicular fluid and serum metabolites in Holstein cows are predictive of genetic merit for fertility
This study examined the metabolite profile of serum and follicular fluid on Day 7 of the oestrous cycle in Holstein cows with good or poor genetic merit for fertility. Differences between the two genotypes in the abundance of fatty acids and amino acids were highly predictive of fertility. The results demonstrate that metabolite profiles in cattle respond to genetic selection for fertility traits, and specific metabolites may be useful biomarkers for fertility
RD15239Suppression of Sertoli cell tumour development during the first wave of spermatogenesis in inhibin α-deficient mice
Testicular cancer is the most common malignancy among young men; however, the mechanisms driving tumour growth are unclear. Herein we show that Sertoli cell tumours in the adult mouse testis can be profoundly suppressed by short-term inhibition of the pituitary hormone FSH in early postnatal life. These results show that FSH protects against Sertoli cell tumour growth during discrete windows of testicular development.
RD15145Retinoic acid triggers c-kit gene expression in spermatogonial stem cells through an enhanceosome constituted between transcription factor binding sites for retinoic acid response element (RARE), spleen focus forming virus proviral integration oncogene (SPFI1) (PU.1) and E26 transformation-specific (ETS)
Regulation of c-kit during spermatogenesis remains largely unknown. Retinoic acid (RA) regulates c-kit expression through discrete promoter regions. An enhanceosome constituted between transcription factor binding sites RARE, PU.1 and ETS in response to RA play an imperative role in c-kit activation. RA-induced c-kit regulation may provide insights in the understanding of nuances between self renewal and differentiation of spermatogonial cells.
Is sperm DNA fragmentation (SDF) involved in the lower fertilising ability of cryopreserved spermatozoa from cancer patients? In this study we evaluated SDF in two different cytometric sperm populations (PIbrighter and PIdimmer). In cryopreserved spermatozoa from cancer patients, PIbrighter SDF, which is more relevant to reproduction, was positively related to sperm motility and that the proportion of these cells was higher in samples from cancer versus non-cancer (oligozoospermic or affected by autoimmune pathologies) patients. The results of the study indicate that thawed motile spermatozoa of cancer patients may carry DNA damage.
It is now possible to reliably collect crocodile semen for fertility evaluation and AI. Herein we describe a validated method for assessing the quality of crocodile sperm DNA using the sperm chromatin dispersion test. This technique, a first for any reptile, will now be used for refining improved methods of crocodile sperm preservation.
RD15238Effect of bovine oviductal fluid on development and quality of bovine embryos produced in vitro
The post-fertilisation culture environment in vitro determines embryo quality, and different strategies have been developed to improve culture conditions. The use of bovine oviductal fluid supplementation during in vitro culture had a positive effect on embryo development and embryo quality. Thus, by mimicking in vivo conditions using animal models, we could improve assisted reproductive technologies applied to both domestic species and humans.
RD15269Peri-ovulatory endocrine regulation of the prostanoid pathways in the bovine uterus at early dioestrus
In cattle, sex steroids modulate pre-implantation uterine function, embryo receptivity and consequently, fertility. Prostaglandins (PGs) are synthesised in the endometrium and influence conceptus growth and corpus luteum lifespan. Here, we examined the biosynthetic pathway of PGs and determined that distinctly different pro-oestrus concentrations of oestradiol and dioestrus concentrations of progesterone did not affect endometrial PG production during the first week after oestrus. The influence of PGs in fertility occurs at later time points of gestation.
RD15103Cytokine gene expression at the maternal–fetal interface after somatic cell nuclear transfer pregnancies in small ruminants
The reasons why somatic cell nuclear transfer (SCNT) pregnancies are at increased risk of pregnancy loss are poorly understood. This study investigated pregnancy losses and gene expression of inflammatory mediators in sheep and goat SCNT pregnancies. Sheep SCNT pregnancies had an increased incidence of pregnancy loss and increased expression of inflammatory cytokines in the placenta, which indicates the presence of an unfavourable environment for fetal development.
RD15016Caudal vena cava progesterone and LH release patterns on Day 14 of gestation in primiparous sows
To date, not much is known about the interaction of progesterone and LH, nor progesterone’s metabolism during early pregnancy in the sow. This study of the release pattern and concentration of progesterone in the caudal vena cava, following LH pulses revealed their temporary relation and confirmed postprandial decrease of progesterone. Already on day 14 of an individual sow’s second pregnancy, the function of the CL seems to be affected by LH.
Spix’s yellow-toothed cavies (Galea spixii) are hystricomorph rodents. The ovarian preantral follicle (PF) population of G. spixii was characterised in the present study. It was estimated that the PF population per ovarian pair was 416.0 ± 342.8 (mean ± s.e.m.). Moreover, after a solid surface vitrification process using dimethyl sulfoxide as the cryoprotectant, 69.5% of PFs were morphologically normal.
RD15172Thyroid function and autoimmunity during ovarian stimulation for intracytoplasmic sperm injection
The role of thyroid hormones in implantation and early embryo development has been highlighted recently because of the increased use of assisted reproduction technology (ART). Close examination of thyroid function in women undergoing ovarian stimulation shows that thyrotropin-stimulating hormone (TSH) concentrations could increase during the procedure, particularly in women who become pregnant. If this is true, special care, such as universal baseline screening, has to be considered for women undergoing ART.
Can paternal experiences be transmitted to offspring? Here we show that mating of immunised male mice with unimmunised females significantly altered gestation conditions and in utero embryo development resulting in increased embryonic bodyweight. These results emphasise that, as active environmental explorers, males confer their experiences to their progeny, suggesting an important mechanism of population-wise adaptation to infectious load.
Our study evaluated how the stria vascularis and organ of Corti develop in miniature pigs. The stria vascularis develops during the embryonic period, concurrent with maturation of the organ of Corti in miniature pigs. The magnitude of endocochlear potential reached a steady state when the stria vascularis was morphologically adult-like at E98. These findings provide a morphological and functional basis for future animal studies of various inner-ear diseases.
Given the great potential of extracellular vesicles as biomarkers for detecting early-stage disease – in particular pre-eclampsia – here we have reviewed the characteristics of placenta-shed vesicles and conducted a meta analysis of their protein content, which has revealed significant variability. Achieving the goal of biomarkers for pregnancy disorders will depend on rigorous standards for isolation and detection of placenta-derived vesicles.
RD15270Inducing ovulation with oestradiol cypionate allows flexibility in the timing of insemination and removes the need for gonadotrophin-releasing hormone in timed AI protocols for dairy cows
The induction of synchronous ovulation and determination of the time of insemination are critical steps for the success of timed AI (TAI) in dairy cattle. The addition of gonadotrophin-releasing hormone (GnRH) had no beneficial effect on tightening the time to ovulation when oestradiol cypionate was used, and similar pregnancy rates were achieved when AI was performed 48 or 54 h after device removal. Thus, inducing ovulation with oestradiol cypionate removes the need for GnRH and can be a cost-effective and flexible option for TAI in dairy herds.
RD15179Cytoplasmic membrane activities during first cleavage of zona-free porcine embryos: description and consequences
Eggs are used in mammals for experiments and fertility treatment, but new ways to determine their quality are still needed. Using the pig as a model, eggs had their surrounding shell removed to visualise finer details in cell membranes during cleavage, showing new patterns reflecting their normality or otherwise. These observations supplement traditional egg evaluations, but require validation in other types of embryos from other mammals.
The cheetah population under human care is notoriously difficult to breed and scientists need to gather as much biological data as possible to overcome issues ranging from behavioural compatibility to infertility. This work found that male cheetahs managed in small, closely bonded groups experience increased testicular function, including higher sperm quality, compared to males housed singly. These findings support existing management practices to improve breeding efforts to build assurance populations of cheetahs.
RD15192Nutrient restriction in early ovine pregnancy stimulates C-type natriuretic peptide production
C-type natriuretic peptide (CNP) may be required for support of the developing conceptus during pregnancy. We explored this by placing pregnant ewes on a restricted diet and found that their blood levels of CNP were elevated in comparison with ewes on a normal level of nutrition. Elevation of CNP levels may be an adaptation to enhance placental function when fetal development is impaired.
Nucleolar precursor bodies (NPBs) are mandatory entities of mammalian zygotes, but their relation to nucleolus-like bodies (NLBs) of fully-grown oocytes remains vague. Here, we show that NPBs, unlike NLBs, are impoverished for RNA and rRNA despite of both bodies contain rRNA-binding proteins. We suggest a scheme for NPB assembly and transformation to functional nucleoli that supposes utilization of oocyte-derived nucleolar proteins but mainly of nascent rRNAs.
RD15050Effects of testosterone and prolactin on steroidogenesis in post-ovulatory cumuli oophori and on in vitro oocyte fertilisation in the rat
Could a supplement hold the key to understanding the mechanism of progesterone production by the postovulatory cumulus-oocyte complexes (COCs)? In the research various supplements influencing progesterone production by rat COCs containing unfertilised or fertilised oocytes have been tested in vitro, suggesting that the hormone mixture of prolactin and testosterone increased progesterone synthesis and oocyte fertilisability. This might prompt a wider research on the use of this mixture to increase the IVF success rates also in other species.
Earlier studies have shown that in vitro supplementation of DHA produced inconsistent results on the quality of frozen–thawed bull semen. This work aimed to overcome the variations reported previously. Results showed that 3 ng mL–1 DHA supplemented in BioXcell extender improved all sperm parameters compared with the control and other groups. The successful incorporation of DHA into the cell membrane before freezing protected the spermatozoa from disintegration caused by ice crystals.
Over the last decade important advances have been made in the area of ovarian function using color-Doppler ultrasonography. Herein we investigated the influence of dimensions and vascularity of the preovulatory follicle (POF) wall as indicators to predict the size, blood flow, and capacity of progesterone production of the subsequent CL in cows. Strong correlations and linear associations between POF and/or CL dimensions and blood flow with systemic progesterone concentrations from the resultant CL were observed. Selection of POFs with greater blood flow is likely to result in CLs with improved potential for plasma progesterone production.
The ultrastructure of the spermatogenesis in agoutis help to identify the processes that affect infertility and the use of biotechnologies related to reproduction. The Leydig and Sertoli cells undergo morpho-physiological changes during sexual development, especially in the prepubertal phase. The spermatozoon of agouti had a tapered head without prominence of the acrosome and no evidence of the perforatorium. There is evidence of degeneration of centrioles in completely formed spermatozoa. In order to deepen the knowledge on spermatogenesis of agouti kept in captivity, this work highlights the importance of reproduction in wild species for their preservation and rational creation.
RD15152Swim-up of tammar wallaby (Macropus eugenii) spermatozoa in Biggers, Whitter and Whittingham (BWW) medium: maximisation of sperm motility, minimisation of impairment of sperm metabolism and induction of sperm hyperactivation
For the first time in a marsupial species, this study visually revealed that spermatozoa of the tammar wallaby can be quickly induced into a hyperactivated pattern, a necessary condition that enables spermatozoa to fertilise eggs in nature. The study also identified that BWW medium is able to maintain sperm motility, metabolism and viability better than other commonly used media. As there has been no success with IVF in any marsupials so far, this information could enable researchers to develop a proper IVF protocol for endangered marsupial species.
RD15246Kinetic effect of oestrogen on secretion of prostaglandins E2 and F2? in bovine oviduct epithelial cells
Prostaglandins are important factors in mediating fertilisation and establishing pregnancy. In this study we investigate the effect of oestrogen on prostaglandin E2 (PGE2) and prostaglandin F2α (PGF2α) secretion and the role of synthase on PGE2 and PGF2a production in bovine oviduct epithelial cells. The findings suggest that exogenous oestradiol, PGE2 and PGF2α may modify bovine oviduct reproductive endocrine dysfunction.
RD15128Differential gene expression in the endometrium reveals cytoskeletal and immunological genes in lactating dairy cows genetically divergent for fertility traits
We examined the global gene expression profile of endometrial tissue on Day 7 of the oestrous cycle in Holstein cows with good or poor genetic merit for fertility traits. Three physiologically relevant networks of genes were identified: (1) actin and cytoskeletal components; (2) immune function; and (3) ion transportation. This study has identified three important areas for future research.
RD15226Combinatorial effects of epidermal growth factor, fibroblast growth factor 2 and insulin-like growth factor 1 on trophoblast cell proliferation and embryogenesis in cattle
In vitro embryo culture is gaining popularity in various species as a means for generating pregnancies. In this study, supplementing culture medium with uterine-derived factors improved bovine placental cell proliferation and embryo development. These findings support the contention that providing selective uterine-derived factors during early embryo culture improves embryo competency for maintaining viable pregnancies and producing healthy offspring.
The presence of two canine fetuses within one placental site has been rarely documented in the literature. In this case report, we describe the finding of monochorionic canine fetuses of discordant gender, with co-mingling of the fetal blood supplies. Abnormal sexual development was discovered in both fetuses, which, in the female, resembles freemartinism, a phenomenon not previously reported in this species.
The maternal diet can alter the bodyweight and immune programming of subsequent generations. A maternal hypercaloric diet (HD) during puberty and early adult age induces overweight in the F1 generation and increases peripheral inflammation despite the feeding of a normocaloric diet to the F1 generation. It also induces adaptative patterns of the hypothalamic glial response towards a state of neuroprotection. These data reveal a transgenerational effect of the HD that may occur, in part, through permanent changes in immune and nervous system programming.
Seminal plasma proteins (SPP) support survival of ram spermatozoa, exerting a dual effect, both capacitating and decapacitating. The addition of SPP before in vitro capacitation with epidermal growth factor induced a decrease in progressive spermatozoa and an increase in hyperactivated spermatozoa. Ram spermatozoa are able to undergo capacitation with no hyperactivation and SPP are able to induce hyperactivation in spermatozoa but maintain them in a decapacitated state.
RD15160Effect of C-type natriuretic peptide on maturation and developmental competence of immature mouse oocytes in vitro
Being able to induce meiotic arrest, C-type natriuretic peptide (CNP) provides a new alternative to improve the synchronisation of nuclear and cytoplasmic maturation of oocytes matured in vitro. In the present study, temporary meiotic arrest induced by CNP significantly improved maturation and the subsequent development of mouse immature oocytes in vitro. These results indicate the potential value of CNP in improving the efficiency of oocyte IVM.
RD15132Nuclear transfer alters placental gene expression and associated histone modifications of the placental-specific imprinted gene pleckstrin homology-like domain, family A, member 2 (PHLDA2) in cattle
Comparing placental development of bovine embryos produced naturally, by IVF and by cloning would allow for improvements in animal production using assisted reproductive techniques. The present study demonstrates that gene expression of the imprinted gene pleckstrin homology-like domain, family A, member 2 (PHLDA2) is higher in early stage cloned placentas. This increase in PHLDA2 mRNA is associated with changes in the epigenetic event of histone methylation.
The reproductive performance of offspring in adulthood is determined during fetal and neonatal development. The aim of the present study was to explore the effect of intra-uterine growth restriction on the reproductive performance of offspring. Growth restriction affected sperm production via reproductive organ development and epigenetic regulation. These results provide evidence for the effects of prenatal development on programming reproductive performance in male offspring.
RD14393Selection of reference genes for quantitative real-time polymerase chain reaction in porcine embryos
The gene expression pattern varies between porcine embryos produced by different methods and to analyse these changes normalisation against reference genes is routinely employed. However, these reference genes should be carefully chosen for evaluation as they also tend to have variable expression. In our study using three different analysis programs, we determined that SDHA and H2A are the most-stable reference genes that can be used for accurate normalisation to obtain reliable results.
RD15186Changes in aquaporin 5 in the non-ciliated cells of mouse oviduct according to sexual maturation and oestrous cycle
Aquaporins (AQPs) play an important role in fluid homeostasis in epithelia. To understand oviductal fluid homeostasis, AQP5 expression was examined in immature and cycling female mice. In oviduct epithelia, AQP5 in non-ciliated cells was increased by gonadotropin in immature mice and peaked during oestrus in cycling females, suggesting its participation in fluid homeostasis in oviduct epithelia.
RD15151Puberty onset is delayed following uteroplacental insufficiency and occurs earlier with improved lactation and growth for pups born small
Growth restriction increases the risk of developing disease in adulthood, with the postnatal environment playing a critical role. This study identified the effects of prenatal and postnatal growth restriction on puberty onset and metabolism in growth restricted rats. The results show that growth restricted males and females had a delayed puberty onset, with altered sex-hormone concentrations and reduced leptin. Improvement of postnatal nutrition leads to a restoration of plasma leptin concentrations and rectification of the timing of puberty onset.
RD15251Time within reproductive season, but not age or inbreeding coefficient, affects seminal and sperm quality in the whooping crane (Grus americana)
The whooping crane underwent a severe genetic bottleneck in the early 1940s. The present study demonstrates that time of breeding season, but not inbreeding coefficient, affects the seminal characteristics of cranes maintained ex situ. The findings will serve as an important foundation for efforts in incorporating AI with frozen–thawed semen into genetic and demographic management of this endangered species.
RD15004Follicular size and stage and gonadotropin concentration affect alginate-encapsulated in vitro growth and survival of pre- and early antral dog follicles
This study aims to understand the complex dynamics of dog folliculogenesis through in vitro studies. This study demonstrates that both preantral and early antral stage follicle grow significantly in vitro with FSH, but not LH, being a key regulator. The findings serve as important foundation for the establishment of in vitro follicle culture system for rescuing maternal genomes in domestic and wild canids.
RD15150Mitogen-activated protein kinase-activated protein kinase 2 is a critical regulator of pig oocyte meiotic maturation
Oocyte quality is critical for female reproduction. Using a pig oocyte model, this study revealed the important role of mitogen-activated protein kinase-activated kinase (MK2) in regulating meiotic resumption and spindle organization, as well as euploid oocyte production. This will contribute to understanding the causes of female infertility and improving the success of assisted reproduction.
The mechanisms underlying follicle selection in monovular species are largely unknown. We assessed the involvement of FGF7 subfamily members in follicle selection in cattle and found that expression of ligands and receptors is upregulated in subordinate vs dominant follicles during follicle deviation, and that FGF10 inhibits oestradiol secretion and expression of FSHR and IGF1R in granulosa cells. These data point to an important role for FGF10 in follicle selection.
Reduced glutathione (GSH) improves the fertilising ability of frozen–thawed boar spermatozoa. The present study investigated the relationship between acrosin activity and reproductive performance in frozen–thawed boar spermatozoa and the effects of GSH. The results show that GSH counteracts the decrease in acrosin activity in good but not poor freezability ejaculates and suggest that the increase in reproductive performance mediated by GSH could be related to acrosin activity.
Studies on subsequent reproductive performance of low birth weight gilts are limited. The effects of birth weight on the development of the reproductive tract and puberty onset were investigated herein, and both parameters seem equivalent in different birth weight gilts. As birth weight may be an important parameter to include in dam line breeding programs, a better understanding of the impact of birth weight on fertility seems critical.
RD15180Retinoic acid treatment alters germ cell heterogeneity and testicular echotexture in prepubescent ram lambs
Scrotal ultrasonography can be employed to study testicular development but echotextural characteristics of specific germ cell types remain unknown. Retinoic acid (RA) given to prepubescent ram lambs reduced the variation in germ cell populations, which corresponded with a significant change in numerical pixel values (brightness) of the testicular parenchyma. RA manipulation of spermatogenic function, particularly in sexually immature animals, may provide a useful model for further investigations into the non-invasive ultrasonographic monitoring of spermatogenesis.
These articles have been peer reviewed and accepted for publication. They are still in production and have not been edited, so may differ from the final published form.
The Current State of Reproductive Biology Research in Australia and New Zealand: Core Themes from the Society for Reproductive Biology Annual Meeting, 2016
The presence of VEGF during the first half of in-vitro maturation improves the meiotic and developmental competences of porcine oocytes from small follicles
Regulation of the heat-inducible HSPA1A gene expression during maternal-to-embryo transition and in response to heat in in vitro-produced bovine embryos
The effect of nutritionally-induced hyperlipidemia on in vitro bovine embryo quality depends on the type of the major fatty acid in the diet
Effect of prostaglandin E2 and F2Î± on adiponectin system expression in the porcine uterus during early pregnancy
Sleep restriction in Wistar rats impairs epididymal postnatal development and sperm motility in association with oxidative stress
Effect and possible mechanisms of melatonin treatment on the quality and developmental potential of aged bovine oocytes
Cerium oxide nanoparticles (CeO2 NPs) improve the developmental competence of in vitro matured prepubertal ovine oocytes
Time within reproductive season, but not age or inbreeding coefficient, influences seminal and sperm quality in the whooping crane (Grus americana)
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