Reproduction, Fertility and Development
Steroid hormone fluctuations during the mammalian oestrous cycle can be differently affected by dietary ω3 and ω6 polyunsaturated fatty acids (PUFAs). In this study we determined the effects of plasma free PUFA patterns on the guinea pig oestrous cycle and found positive effects of ω3 PUFAs on sex hormone concentrations and negative effects on cortisol concentrations only in oestrus, whereas the effects of ω6 PUFAs were detrimental. The findings demonstrate opposite and selective contributions of PUFAs during different stages of the oestrous cycle and a high biological relevance of plasma free PUFAs.
The Kiss1 gene plays a major role in reproductive seasonality of sheep. This study aimed to confirm that epigenetic modification occurs in sheep during the reproductive cycle. A potential role of histone acetylation modification in altering Kiss1 expression, which may consequently regulate seasonal breeding in sheep, was found. This study may offer a theoretical basis for breeding year-round oestrous sheep.
Polycystic ovary syndrome (PCOS) is one of the most common causes of female infertility. A-Kinase anchor protein 95 was found to be involved in the development of PCOS by regulating aromatase. The findings of this study will help us better understand the pathogenesis of PCOS and may help with the clinical diagnosis and prognosis of PCOS in the future.
Ionomycin is a Ca2+-selective ionophore commonly used in assisted oocyte activation (AOA), to overcome failed fertilisation. We investigated the effect of external ionomycin and Ca2+, supplemented to the culture media during AOA, on activation efficiency and embryonic developmental potential, in both mouse and human oocytes. The demonstrated effect of commercial medium on the pattern of Ca2+ release and further embryonic developmental potential should be considered when applying AOA in the clinic.
Due to fetal and neonatal bone tissue calcification, the maternal calcium demand increases during pregnancy and lactation. To supply this calcium demand, female mammals undergo numerous physiological changes during reproduction. In the present study, we performed a meta-analysis of studies reporting changes in bone mineral density, serum calcium and calciotropic hormone concentrations during pregnancy and lactation in mammals. The results provide a quantitative background to better explain and understand these physiological adaptations.
Female sperm storage is known across many animal phyla, but the mechanism(s) remains elusive. Using the Indian garden lizard, Calotes versicolor as a model, we identified a unique abundant protein of ~55-kDa in the uterovaginal region that controls the motility of the spermatozoa. These studies are likely to unravel the secrets of sperm storage.
The molecules that are involved in actin-based oocyte polar body extrusion are still largely unknown. In the present study we showed that knockdown of Profilin caused aberrant actin distribution, the failure of polar body extrusion and altered the expression of Rho-associated kinase (ROCK) and myosin light chain (MLC) 2. The results indicate that Profilin is related to ROCK–MLC2 for actin assembly in mouse oocytes.
Fertility loss is a major problem in roosters in the commercial poultry industry. The aim of the present study was to investigate the effects of orally administered d-aspartate on the reproductive performance of roosters. The findings reveal that the positive effects of d-aspartate are probably mediated via changes in gene expression and testicular histology. This study shows that dietary supplementation with d-aspartate is an easy and practical strategy to mitigate the reproductive loss in roosters.
Thirty-nine metabolites, including 14 amino acids, were identified in the bovine oviductal fluid. Regardless of the cycle stage or ovulation side, lactate, myo-inositol and glycine were the most abundant metabolites. The fold changes in metabolite levels between stages or ovulation sides were less than 1.7 except for glucose-1-phosphate which was highly regulated across the estrous cycle.
Bats are excellent indicators of environmental quality and their reproduction is affected by climate change. This study highlighted the effects of body condition and seasonality on reproductive behaviour, demonstrating changes in the morphofunctional parameters of the testes between rainy and dry seasons.
This research provides new insight into central molecular mechanisms regulating GnRH/LH secretion in anestrous sheep. To better explain this problem, herein, we demonstrated that RF-amide peptides are involved in dopamine-induced inhibition of GnRH/LH secretion. Studies expanded an important issue in the field of neuroendocrinology of reproduction, especially in cognitive appraisals of mechanisms participating in physiological regulation of GnRH/LH biosynthesis.
This study mainly explored the effects of nutrition on seasonal patterns of the ovine estrus cycle in the non-breeding season. Based on low or high nutrition levels, it was found that two nutritional factors (tyrosine and folic acid) were involved in the regulation of oestrous pathways during the anestrous season, and the GNAQ gene is an important regulatory hub between nutritional and photoperiodic regulation of seasonal breeding in sheep.
This study is the first to demonstrate that the transcription factor cAMP response element-binding protein 1 (CREB1) controls ovarian cell proliferation and apoptosis without having to be phosphorylated, but it does not mediate the effects of the upstream hormonal regulators. CREB1 appears to be a novel intracellular regulator of reproduction.
Maternal undernutrition may lead to fetal intrauterine growth restriction (IUGR). This study revealed that arginine supplementation to underfed ewes ameliorated fetal IUGR by improving metabolic homeostasis of fetal endocrinology, increasing the availability of amino acids in tissues and affecting the expression of somatotropic axis genes. This indicates that arginine could mitigate significant decreases in fetal growth due to maternal undernutrition.
This work examined the presence and localisation of AQP11 in bull spermatozoa. We observed that AQP11 is localised in the head and tail of bull sperm cells and that it is related to bull sperm cryotolerance. In addition, the relative AQP11-content in fresh bull semen was found to be correlated with reproductive outcomes evaluated both in vitro and in vivo.
N-carbamylglutamate (NCG) and arginine (ARG) supplementation can increase litter size in pigs and rats, but their effects on gonadotrophin-releasing hormone (GnRH) secretion are unknown. We found that NCG and ARG can increase cell numbers and decrease GnRH secretion in murine immortalized GT1-7 cells in vitro by regulating related gene expression. These findings help us to better understand nutritional control of reproduction.
It is well documented that oocytes from super stimulated heifers are less competent compared to sexually mature cows. In this study, we characterized the changes in granulosa cells gene expression within the same heifers approaching puberty following ovarian stimulation. We found a lower level of signaling in: cell differentiation, inflammation and apoptosis, suggesting an insufficient support of luteinizing hormone during FSH withdrawal.
Early pregnancy loss compromises reproduction in horses; up to 20% of pregnancies diagnosed by Day 15 fail, mostly before Day 40. Daily monitoring of conceptus growth (by ultrasound) and maternal blood progesterone concentrations (by radioimmunoassay) during 16 spontaneous losses between Days 13 and 25 has revealed that luteolysis might contribute to early loss more often than previously contended, with implications for the experimental investigation and clinical management of the problem.
Adiponectin may be a potent therapeutic agent for recovery of the polycystic ovary syndrome (PCOS) condition. The aim of the present study was to unravel the role of adiponectin in regulating reproduction, metabolism and fertility status in mice in which PCOS had been induced. Reversal of PCOS-like features following adiponectin treatment in mice is a major breakthrough with regard to the effective management of PCOS.
Animal cloning is a very inneficient process in many mammalian species. The successful establishment of pregnancy is dependent on a controlled interaction between the developing placenta and the maternal immune system. We observed an altered expression of genes related to inflammation, growth and apoptosis in placentas of cloned sheep, which likely contribute to the placental dysfunction and fetal overgrowth observed in these pregnancies.
Transplantation of ovarian tissue is a good alternative to study follicular development after cryopreservation because in vitro culture is still a major challenge. The present study compared fresh and vitrified goat ovarian tissue after autotransplantation and in vitro culture. Antral follicle formation was observed 3 months after autotransplantation of fresh and vitrified goat ovary and ovarian function was restored.
Do extracellular vesicles have a biological role in the communication between the embryo and its microenvironment during in vitro culture? In this study we showed that embryos were able to incorporate microvesicles obtained from endometrium and amnion, but only amniotic progenitor cell-derived microvesicles resulted in better blastocyst production rate and quality compared to control. This study could be a useful starting point for further studies related to paracrine mechanisms of communication between embryos and the culture medium.
Nutritional perturbation during early gestation has been shown to alter male reproductive development in rodents and sheep. This study examined the effects of dietary protein perturbation during the peri-conception and first trimester periods upon reproductive development in both fetal and pubertal male bovine progeny. Low maternal dietary protein negatively impacted reproductive development in pubertal and postpubertal offspring. This research highlights that further studies are warranted to explore causal relationships between gestational nutrition and consequent postnatal male reproductive development in cattle.
Testicular regression after to exposure a short photoperiod in Syrian hamster is a good model in which to study changes in the population of Leydig cells. During regression, the number of Leydig cells decreases and three types of cells (A, B and C) are observed. Type B and C cells exhibit characteristics of necrosis, which implies that elimination of Leydig cells must be the result of necrosis and/or necroptosis.
Kisspeptin peptide is a major regulator of initiation of pubertal actions in the central nervous system, but its development in growing animals is obscure. The presence of kisspeptin neurons in the brain from birth to puberty in relation to luteinising hormone release pattern was analysed in female lambs. Activity of kisspeptin neurons increased gradually parallel with augmentation of luteinising hormone release and reached maturation several weeks before puberty. The participation of kisspeptin in the development of the ovine reproductive processes is suggested.
The preimplantation period of pregnancy is a critical period for determining growth of the conceptus. This study examined the use of progesterone treatment as a means of overcoming maternal constraint effects on embryo growth. Exogenous progesterone was found to indirectly advance embryo growth via alteration of endometrial genes that encode for uterine structural and secretory activity and thereby overcome maternal constraint.
The zona pellucida (ZP) is an extracellular matrix formed by a few glycoproteins that covers the oocyte and plays an important role during fertilization. The identification of the components of the ZP in marsupials is relevant for the cellular understanding of female gamete formation, sperm interaction with the ZP and fertilisation. Molecular and in silico analyses demonstrated a different ZP composition between Australasian and South American marsupials, being formed from four to six proteins. The present findings have potential relevance from a biological, ecological and economic point of view, related to the development of new contraceptive vaccines for marsupials.
This article contributes to a better understanding of which transcripts are involved in early embryonic development, when the embryos still rely on the maternal genetic component and after they activate their own genome. We identified the thyroid hormone receptor, especially the β-subunit, as one of the few genes transcribed before major embryonic genome activation with an essential role for development.
To improve current infertility treatments, it is necessary to evaluate uterine receptivity in each menstrual cycle. If this can be evaluated beforehand, when uterine receptivity is inadequate eggs could be stored using cryopreservation. In this study in a mouse model, we identified an electrophysiological parameter that can evaluate uterine receptivity prospectively.
Genistein, biochanin A and formononetin are phyto-oestrogens that cause ‘clover disease’, a serious disruption of reproduction in sheep. All three phyto-oestrogens, when present during in vitro maturation of ovine oocytes, will disrupt subsequent fertilisation and embryo development. These observations help explain clover disease, and also show how artificial reproductive technology could be used to screen forage species before industrial release.
Angiogenesis is a vital process in the development and survival of lesions during endometriosis. In the present study we identified upregulation of several isoforms of vascular endothelial growth factor (VEGF) A in the endometrium of women with endometriosis during menstruation and, for the first time, identified the natural expression of the VEGF111 isoform in humans. These findings contribute to our understanding of how the endometrium differs in women with endometriosis, and indicates a dysregulation at the critical time of menstruation.
In mammals, the success rate of oocyte activation is one of the main factors that influences the efficiency of parthenogenetic activation (PA) and somatic cell nuclear transfer (SCNT). In this study, a new oocyte-activated reagent, JNJ-7706621, was applied in the production of porcine PA and SCNT embryos and was found to improve in vitro developmental competence by suppressing the level of MPF.
Activin C can delay the growth of mouse granulosa cell tumours, but little is known about its function in normal ovaries. This study shows that activin C protein is expressed in normal mouse and human ovaries, and can delay the development of abnormal follicles in mice lacking inhibin, but does not appear to alter normal follicle growth in the mouse. This study provides evidence of a role for activin C in the ovary.
Prostate development and function are altered by early postnatal exposure to prolactin imbalance. Prolactin modulation interferes with the determination of ventral prostate development and maturation through a mechanism of increasing the epithelial proliferative response and dynamics of cell differentiation. Changes in prostate morphophysiology after prolactin modulation could affect glandular function and the incidence of disorders associated with aging.
Milk fat globule-EGF factor 8 protein (MFGE8) is a protein that promotes cell to cell adhesion and is thought to play an essential role in embryo implantation in mice and humans. We have described the expression of MFGE8 in the equine uterus and found particular strong expression of the protein by the fetal portion of the placenta. These results imply a role for MFGE8 in maintaining an intact placenta during mare pregnancy.
The role of melatonin as an endocrine regulator of reproductive activity is well known; however, whether it stimulates or inhibits reproductive function varies across species. We demonstrated that in vitro exposure to melatonin reduced steroid production by ovarian theca cells in cattle, implicating melatonin as a regulator of reproductive function in cattle. Because reduced reproductive capacity leads to economic losses, an understanding of the effects of melatonin on ovarian function may lead to new ways to increase reproductive efficiency in cattle.
Signalling pathways responsible for follicular activation in the mare remain uncharacterised. Messenger RNA expression and protein localisation of members of the PI3K/AKT and JAK/STAT pathways were analysed using tissue from fetal and adult mare ovaries. Findings suggest that members of these pathways are indeed present and may serve as useful biomarkers for assessment of ovary development in the horse.
The forkhead box (Fox) gene family encodes multiple forkhead proteins that exhibit marked functional diversity and are involved in biological processes, especially sex differentiation. The identification, characterisation, selective pressure, protein structure and expression pattern of Fox genes in response to temperature were investigated in the present study in the Chinese giant salamander Andrias davidianus to enrich the sexual development and reproduction mechanism in amphibian.
During cryopreservation, spermatozoa undergo cryodamage because of membrane changes, including sterol loss, which results in diminished post-thaw fertilisation ability. The present study showed that loading of cholesterol and desmosterol into chicken spermatozoa prior to cryopreservation enhanced their post-thaw quality by inhibiting apoptotic changes and premature acrosome reaction, providing new mechanistic insight into cryodamage in chicken spermatozoa.
During preimplantation development, the bovine embryo is free floating in oviduct and uterine fluids. We aimed to mimic the physiological conditions of the maternal environment in the present study by supplementing serum-free embryo culture medium in vitro with both fluids sequentially. The results revealed that low concentrations of oviduct and uterine fluids support early embryo development and improve blastocyst quality.
Uncontrolled inflammation of the oviduct can result in tubal occlusion and infertility. This inflammation is often in response to infection with sexually transmitted bacterial pathogens. This study describes how the endotoxin from Escherichia coli-derived lipopolysaccharide affects the expression of inflammatory mRNAs and post-transcriptionally modifying miRNAs within the oviduct, providing novel insight into the molecular regulation of inflammation within this key reproductive organ.
Reproductive research is essential to our understanding of the factors contributing to a healthy pregnancy, birth and child. This review of the 2017 Annual Meeting of the Society for Reproductive Biology summarises the key themes, significant questions and emerging technologies presented in the symposia. In particular, it highlights the importance of the pre- and periconceptional environment for setting a suitable trajectory for offspring health well into adulthood.
The reason why some spermatozoa reach the site of fertilisation where others fail is not known, but interaction between spermatozoa and the female environment is key. We profiled ‘winner’ and ‘loser’ spermatozoa and found that the sugars on their surface and their susceptibility to immune cell attack differed significantly. This helps to explain both normal reproductive physiology and the consequences of human intervention.