Reproduction, Fertility and Development
Number 11 2016
Subclinical mastitis is associated with reduced fertility in dairy cows; however, the underlying mechanism is not entirely clear. Herein we provide evidence, for the first time, that subclinical mastitis induces changes in oocyte maturation in association with reduced developmental competence. Effects were observed at both the cellular and molecular levels following the induction of subclinical mastitis using toxins of Staphylococcus aureus (Gram-positive) or Escherichia coli (Gram-negative) origin.
The oviductal and uterine cellular remodelling occurring along the estrous cycle (EC) requires a finely tuned intercellular communication. We found that the Notch pathway is enrolled in this cell signalling. Notch genes are differentially transcribed and expressed in the oviduct and uterus along the EC, and this is correlated with progesterone concentrations. Overall, the study implies the Notch pathway as a regulator of the cellular remodelling occurring along the EC.
It is necessary for estrogen to activate embryos at blastocysts stage during implantation. In this research, we explored the mechanism of estrogen action onblastocysts and found estrogen could rapidly cause the relocalisation of integrins in blastocyst cells, and enhanced their affinity with the ligands, so that they attached and implanted into uterine endometrium. Our results suggest a possibility of improving outcome of in vitro fertilisation (IVF).
Administration of a GnRH antagonist for the purposes of oestrous synchronization in a marsupial species is reported for the first time. Injections of azaline B temporarily inhibited the LH response in koalas to exogenous mGnRH and successfully delayed the return to oestrus. Although azaline B clearly disrupts koala folliculogenesis, further investigation and refinement is required to implement this pharmaceutical into an effective oestrous synchronisation protocol.
The aim of this study was to evaluate three fertilisation media (M199, synthetic oviductal fluid (SOF) and Tyrode’s albumin–lactate–pyruvate (TALP)) on IVF performance using female sex-sorted spermatozoa. Embryos derived from SOF and TALP media had higher numbers of ICM, TE and total cells than those fertilised in M199. The fertilisation medium used affected cleavage rate and subsequent embryo development, quality and hatching ability.
Results of two association studies indicate that maternal heritability is a stronger contributor to race performance than paternal heritability in a sample of thoroughbred horses in Australia. In addition, 8–11 years appeared to be the optimal age range of dams for child bearing in relation to their offsprings’ achievements in racing. These findings warrant further research into the significance and contribution of maternal heritability in breeding practice for thoroughbred racehorses.
Maintenance of pregnancy is dependent on the exchange of signals between the conceptus and the endometrium. This is the first report of concurrent transcriptome analysis of conceptus and endometrium in the mare. A plethora of interactions between genes expressed by the conceptus and endometrium 16 days after ovulation in the horse were revealed, providing rationale for further investigation.
Lipids and mitochondria are essential to oocyte and embryo energy metabolism; however, their behaviour during in vitro production of bovine embryos remains unknown. We demonstrated the effects of media supplements on lipid and mitochondrial behaviour during in vitro maturation and their impact on embryo lipid accumulation. Variations in mitochondrial and lipid dynamics caused by in vitro maturation may have negative effects on oocyte development and embryo lipid accumulation.
G9A-like protein (GLP) plays an important role in mouse early embryonic development and Glp-deficient embryos exhibit severe growth retardation and defects that lead to lethality at approximately Embryonic Day 9.5. In this study we investigated the effect of Glp deficiency on in vitro early embryonic development. Knockdown of Glp impaired the pluripotency of mouse embryos. The results of the present study may be applicable to human prenatal diagnosis.
The deleted in azoospermia like (Dazl) gene was initially described as a master regulator of germline specification; however, recent studies indicate that it may have pluripotency-related functions. We generated Dazl–green fluorescent protein-transgenic mice in which the transgene is expressed in both pluripotent and germ cells. These transgenic mice represent a valuable tool for the prospective identification of stem cells from several tissues.
Elevated neonatal androgens act as disturbers of follicular ovarian growth, inducing the formation of cysts in the adult ovary. In this work we analysed the temporal correlation between cyst development and changes in sympathetic ovarian innervation. An increase in density of innervation after cyst development was observed; this could be associated with an attempt to restore normal ovarian activity or as a sign of loss of ovarian functionality.
Bovine somatic cell nuclear transfer embryo-derived stem-like cells were established under defined culture conditions containing three inhibitors of differentiation. Long-term maintenance of stemness and differentiation capacity of the cells was demonstrated. The results have increased our understanding of the state of bovine pluripotent stem cells (PSCs) and provides new insights into the establishment of PSCs in domestic animals.
Discovery of genes associated with the onset of puberty is important for precocious goat breeds. The aim of the present study was to find the genes associated with the onset of puberty in the goat. The results indicate that energy production and conversion may be initiating factors for puberty in the goat. The genes associated with these processes can be validated and may be used in goat breeding.
T cells induced with anti-CD3, anti-CD28, IL-2, and TGF-β1 could prevent spontaneous abortion in mice. Adoptive transfer of CD4+CD25+ or TGFB1-induced Treg cells significantly reduced the fetal resorption rate, increased serum IL10 and TGF-β1 levels, and decreased IFNG levels. Autologous transfer of in vitro TGF-β1-induced Treg cells may represent a novel therapeutic strategy for women with unexplained recurrent spontaneous abortions.
Cumulus cells (CCs) are distinct from other granulosa cells surrounding the egg and the expression of some genes in CCs during maturation may predict oocyte quality. In this study, some genes exhibited differential expression in CCs and could be potential biomarkers for egg development following fertilisation. The expression of these genes could be used for oocyte selection in the fields of animal husbandry and clinical infertility treatment.
For successful reproduction, the uterus needs to be finely regulated by hormones to adapt to its various functions. The aim of this study was to generate gene expression profiles for two cycle stages in the equine uterus, which identified major changes in the expression of genes associated with its morphology, immune system and metabolic processes. Understanding these physiological variations helps distinguish and identify pathologies.
The head morphology of spermatozoa that migrated in a penetration test was evaluated. The relationships among head morphometric characteristics, the ability to penetrate the cervical mucus surrogate and fertility were evaluated. In conclusion, the proportion of spermatozoa with a short and wide head in the fresh sperm sample may be used as a negative predictor of male fertility.
Increased prolactin (PRL) levels during lactation in the koala are regarded as a key factor contributing to female anoestrus. In this study, PRL concentrations in captive lactating koalas remained low until 161–170 days after parturition, at which time concentrations increased significantly. Given that behavioural oestrus was suppressed throughout the majority of lactation, elevated PRL levels do not appear to be the cause of oestrous cycle suppression.
DNA methylation and gene expression of tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) receptors are differed from choriocarcinoma and transformed trophoblastic cell lines. And we showed DNA methylation is associated with TRAIL receptor expression and might be involved in trophoblast apoptosis.
Ovarian tissue transplantation remains risky due to ischaemic–reperfusion injury leading to follicular degeneration or massive activation of follicles from the reserve pool. As oxidative stress might be involved in such a loss, we report herein the use of the antioxidant Trolox, which was able to enhance follicular survival and to avoid extreme follicular activation in grafted ovarian tissue from squirrel monkeys.