Reproduction, Fertility and Development
Number 10 2017
Reproductive science is central to our understanding of biology, translating to biological processes across many organ systems. The Society for Reproductive Biology conference review provides a focused summary of symposia at the 2016 annual meeting. The presentations highlight the breadth of reproductive research in Australia and New Zealand and its potential to affect the fertility and health of future generations.
Poly(A)-binding proteins function in the timely regulation of gene expression during oocyte maturation, fertilisation and early embryo development in vertebrates. In this review, we comprehensively evaluate and discuss the expression patterns and particular functions of the embryonic poly(A)-binding protein (EPAB) and poly(A)-binding protein, cytoplasmic 1 (PABPC1) genes, especially in mouse and human oocytes and early embryos.
Ovaries contain a large number of small follicles, but the meiotic and developmental competence of oocytes from these follicles is quite low. In the present study we demonstrated that the addition of 200 ng mL–1 vascular endothelial growth factor to the IVM medium increased the maturation rate of porcine oocytes from small follicles and that blastocyst formation following parthenogenetic activation also increased. These findings may contribute to efficient animal production and human assisted reproductive technology.
Metronidazole, an essential medicine, adversely affects male fertility. We aimed at investigating the capability of Rosmarinic acid to reverse metranidazole induced male infertility. We found that certain doses of Rosmarinic acid could reverse metronidazole’s effects on sperm count, motility, morphology and testis ultrastructure. Our findings have great clinical implications where Rosmarinic acid might have a potential use in reversing Metronidazole induced male infertility.
A diabetic pregnancy leads to distinct changes in maternal cholesterol metabolism, whereas embryonic cholesterol concentrations and cholesterol metabolism genes are not affected. The trophoblast : embryoblast cholesterol ratio suggests a higher metabolic activity of the embryoblast in diabetes. The findings of the present study imply independent and functional cholesterol metabolism in the mammalian embryo before implantation.
Intracellular lipid is involved in long-term blastocyst competence to survive vitrification. We studied how protein removal affects bovine embryo development in vitro, lipid content and pregnancy outcomes, and found that calf weight at birth was altered depending on specific embryonic kinetics within vitrified–warmed embryos. Therefore, it is possible to modify calf phenotypes by introducing simple changes in culture conditions combined with selection of embryos.
Honey bees, which are vital agricultural pollinators, are at risk from numerous factors. The ability to artificially inseminate these species provides a means to strengthen them genetically by collecting semen from bees of different regions throughout the world and then inseminating bees at distant locations. Our study aimed to substantially improve the viability of spermatozoa between collection and insemination.
Maternal obesity leads to premature aging of male offspring reproductive capacity and increases testes oxidative stress in male rat offspring. Our results show that maternal obesity modifies the antioxidant enzyme system in the testes of offspring, which, in turn, affects testicular physiological functions and leads to premature aging of male reproductive capacity.
In this study we investigated the expression of the LH receptor (LHR) gene during dominant follicle selection in Bos indicus cattle. The main finding was that the early deviation of the dominant follicle in this subspecies is driven by the differential expression of full-length LHR and its isoforms in small follicles. This finding will contribute to explaining the differences in ovarian physiology between B. indicus and Bos taurus.
Kisspeptin neurons in the brain are crucial for the hormone surge required for ovulation, but are established before puberty. This study examined kisspeptin and brain clock gene rhythms (known to restrict kisspeptin action) in young mice. The data show that the kisspeptin peak is not seen prior to puberty and there is incomplete development of clock gene rhythmicity at this time.
The possibility of growing immature human ovarian follicles in laboratories will assist fertility restoration. The aim of the present study was to investigate whether growth of immature follicles can be promoted by using different culture surfaces and supplementation with a growth factor. It was unclear whether any of the culture surfaces had an advantage over the others. In addition, the growth factor did not promote growth. Further studies should test other culture surfaces and identify additional fluid supplements, so that an optimal system can be developed.
Evidence exists that early life nutritional insults can predispose to metabolic disorders, like Type 2 diabetes, for which excessive hepatic glucose production is a contributing factor. Maternal undernutrition alters the epigenetic status of the glucocorticoid receptor and increases the expression of gluconeogenic enzymes in the liver of male offspring. Undernutrition in the womb programs long-lasting changes in specific gene expression that leads to persistent metabolic abnormalities.
Mitochondrial ferritin is an iron-storage protein highly expressed in human and mouse spermatozoa. This work showed that male mice, but not female, in which mitochondrial ferritin was genetically deleted have reduced fertility without significant alterations in sperm parameters. These data show that mitochondrial ferritin has a role in male fertility.
Polydatin (PD) has antioxidant activity and is useful for embryo development in vitro. Supplementation of IVM medium with PD scavenged reactive oxygen species and improved embryo developmental competence via induction of sirtuin 1 (Sirt1).
Improvements in the quality of stallion semen are required to increase the success of artificial insemination. The aim of this study was to assess the effects of the addition of docosahexaenoic acid to semen diluents on the quality of stallion semen. Docosahexaenoic acid increased spermatozoa motility and membrane fluidity in cooled semen and thus can be used to increase the quality of spermatozoa.
The aim of this study was to compare the efficacy of paclitaxel (PT) and docetaxel (DT) in reducing spindle damage in bovine oocytes during vitrification. The important finding of the study was that pretreatment of bovine oocytes with 0.05 µM DT for 30 min before vitrification reduced spindle damage to a greater degree than pretreatment with 1.0 µM PT. This finding will be useful in improving oocyte cryopreservation in the future.
The present study investigated DNA methylation profiles and mRNA expression of imprinted and non-imprinted candidate genes in bovine oocytes from antral follicles of three different size classes (≤2 mm, 3–5 mm, ≥6 mm) to unravel the epigenetic contribution to follicular and oocyte growth. We observed an increased number of aberrantly methylated alleles in bH19, bSNRPN and bDNMT3 Lo of oocytes from small antral follicles and an increased frequency of CpG sites with an unclear methylation status for DNMT3 Ls in large follicles. Results indicate that a follicle diameter of ~2 mm is critical for establishing DNA methylation profiles.
Immune and renal function, both critical for reproductive success, were evaluated to determine if exposure of postreproductive female mice to young ovaries would influence these non-reproductive physiological functions. Postreproductive mice received new (60-day-old) ovaries at 12 months of age and were evaluated at 16 months of age. Age-related declines in immune and renal function in 16-month-old control mice were restored to levels found in 6-month-old mice by ovarian transplantation. Re-establishment of reproductive function in aged female mice positively influenced non-reproductive functions.
The mechanism underlying the non-genomic action of progesterone in sperm functions and related Ca2+ mobilisation remains elusive. Herein we report the expression of gamma-aminobutyric acid type A receptor delta subunit (GABRD) in human and rodent spermatozoa and its involvement in mediating the progesterone-induced acrosome reaction through its interaction with purinergic P2X2 receptors. GABRD represents a novel progesterone receptor or modulator in sperm responsible for the progesterone-induced Ca2+ influx required for the acrosome reaction.
It is still unspecified if and how the number of embryos or fetal sex affect pregnancy outcome. The present study determined whether there are differences in transcriptome profiles of the beaver placenta as a result of fetal sex or multiplicity of gestation. The results indicate that the number of fetuses affects the expression profile in the subplacental transcriptome. Enhancement of transcriptome resources will improve our understanding of the pathways relevant to proper placental development and successful reproduction in general.