Epigallocatechin Gallate From Tea Delays Oocyte Aging After Ovulation in Mice

In clinic, once the ovulated oocytes cannot be fertilized timely, they begin to undergo post-ovulatory aging, which impacts the embryo development and offspring health. Until now, there are no better methods to delay post-ovulatory oocyte aging. Epigallocatechin gallate (EGCG) is the most abundant bioactive component of tea polyphenols that are beneficial for alleviating the deleterious influence of environmental factors on oocyte quality. In the present study, we examined the role of EGCG in delaying oocyte aging after ovulation in vitro. Ovulated oocytes were treated with EGCG at different concentrations, and the fragmentation rate, induced by aging, was significantly reduced by EGCG at 50 μM in vitro. To further elucidate the influence of EGCG on the quality of post-ovulatory aged oocytes, we examined the spindle morphology of aged oocytes. The results showed that EGCG significantly decreased the abnormal rate of spindle morphology in post-ovulatory aged oocytes. The high level of reactive oxygen species (ROS) and mitochondrial dysfunction in post-ovulatory aged oocytes were also improved by EGCG, which might be a reason for the reduced apoptosis. The reduced sperm binding capacity of aged oocytes was increased by the addition of EGCG. These suggest that EGCG can improve the quality of post-ovulatory aged oocytes.