Disruptions in follicle cell functions in the ovaries of rhesus monkeys during summer.

Oocytes isolated from female rhesus monkeys following standard ovarian stimulation protocols during the summer months displayed a reduced capacity to mature compared with stimulation during the normal breeding season. Because the gene expression profiles of oocyte-associated cumulus cells and mural granulosa cells (CCs and GCs) are indicative of altered oocyte quality and can provide insight into intrafollicular processes that may be disrupted during oogenesis, we performed array-based transcriptome comparisons of CCs and GCs from summer and normal breeding season stimulation cycles. Summer CCs and GCs both display deficiencies in expression of mRNAs related to cell proliferation, angiogenesis, and endocrine signaling, as well as reduced expression of glycogen phosphorylase. Additionally, CCs display deficiencies in expression of mRNAs related to stress response. These results provide the first insight into the specific molecular pathways and processes that are disrupted in the follicles of rhesus macaque females during the summer season. Some of the changes seen in summer GCs and CCs have been reported in humans and in other model mammalian species. This suggests that the seasonal effects seen in the rhesus monkey may help us to understand better the mechanisms that contribute to reduced oocyte quality and fertility in humans.