HSP70 overexpression may play a protective role in the mouse embryos stimulated by CUMS

Review of psychological stress on oocyte and early embryonic development in female mice

Psychological stress can cause adverse health effects in animals and humans. Accumulating evidence suggests that psychological stress in female mice is associated with ovarian developmental abnormalities accompanied by follicle and oocyte defects. Oocyte and early embryonic development are impaired in mice facing psychological stress, likely resulting from hormone signalling disorders, reactive oxygen species (ROS) accumulation and alterations in epigenetic modifications, which are primarily mediated by the hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-ovarian (HPO) axes. The present evidence suggests that psychological stress is increasingly becoming the most common causative factor for female subfertility. Here, we review recent progress on the impact of psychological stress on female reproduction, particularly for oocyte and early embryonic development in female mice. This review highlights the connection between psychological stress and reproductive health and provides novel insight on human subfertility.

Protective effects of melatonin on the in vitro developmental competence of bovine oocytes

The present study investigated the effects of melatonin on bovine oocyte maturation and subsequent embryonic development in vitro. Results showed that the nuclear and cytoplasmic maturation, characterized by first polar body extrusion, normal distribution of cortical granules and mitochondria, as well as increased mitochondrial membrane potential, were significantly improved in 10^-9  mol/L melatonin-treated oocytes. Melatonin supplementation reduced intracellular reactive oxygen species level and enhanced glutathione production. Meanwhile, the presence of melatonin (10^-9  mol/L) during oocyte maturation resulted in a decreased early apoptotic rate in oocytes. After in vitro fertilization, oocytes receiving melatonin supplementation exhibited a significantly higher blastocyst formation rate and yielded a markedly lower number of apoptotic cells. Mechanistic explorations showed that addition of 10^-9  mol/L melatonin to in vitro maturation media significantly attenuated the transcript level of caspase-3, while the expressions of BCL-2, XIAP, CAT and HSP70 were significantly reinforced in the resultant embryos. Taken together, melatonin ameliorates bovine oocyte maturation potential, and the beneficial effects can affect subsequent embryonic development. The protective role of melatonin may be due to its anti-apoptotic and anti-oxidative activities.