Reproduction, Fertility and Development
Number 9 2017
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
The deleterious effects of heat stress on fertility are more pronounced in dairy cows than beef cows. The transcriptome profile in Nelore and Holstein oocytes subjected to heat shock during IVM and the mRNA abundance of selected genes in cumulus cells were determined. The analyses indicated that the deficiency in dairy cattle in terms of cellular protection against heat stress is regulated at the post-transcriptional level.
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.
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.
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.
Adiponectin is a hormone perceived as the link between energy metabolism and the reproductive system, but its interactions with factors responsible for regulation of uterine homeostasis during pregnancy remain unknown. Herein we demonstrated the effects of prostaglandins E2 and F2α on adiponectin and its receptors during early gestation. Recognition of these interactions will contribute to our understanding of the physiology of early pregnancy.
Preferential transportation of essential fatty acids over non-essential fatty acids occurs from the mother to fetus in humans. However, little is known about placental transfer of fatty acids in the bovine. In the present study, prepartum dietary fat supplementation of cows reduced maternal long-chain polyunsaturated fatty acids, neonatal total omega-3 fatty acids, eicosapentaenoic and docosahexaenoic acids and total, fat possibly through reduced expression of certain placental fatty acid transporter genes.
Hyperlipidemia associated with unbalanced diet and obesity is directly linked with reduced fertility. This study shows that substituting saturated fat with omega-3 fat in high caloric diets can alleviate detrimental effects of hyperlipidemic serum on bovine early embryo development and quality in vitro. This suggests that dietary manipulation of serum fatty acid profile may enhance fertility in patients with metabolic disorders.
Early mammalian embryos are sensitive to heat stress (HS) despite abundant oocytic iHSPA protein chaperones and mRNAs typically induced by stress. In this work, bovine HSPA1A gene transcription was detectable during embryo genome activation but induced by HS only after this stage, which coincides with better embryonic tolerance. Absence of stress-induced gene expression may therefore contribute to embryo sensitivity.