Chronic restraint stress associations with sperm global DNA hypermethylation: Impacts on male reproductive function in rats.

Recent evidence indicates the involvement of epigenetic mechanisms in the adaptive biological responses to chronic restraint stress. However, the impact of stress on the epigenetic programming of germ cells and subsequent effects on reproductive capacity remain understudied. Therefore, this study aimed to evaluate the effects of chronic restraint stress in sperm global DNA methylation and male reproductive function in Wistar rats. The animals were separated into two groups: the chronic restraint stress group (14 sessions) and the control group. After the final stress session, tissues of all the animals were collected for analysis. The stress group exhibited global sperm DNA hypermethylation (p = 0.0095), reduced sperm motility (p = 0.0079), increased sperm abnormalities (p = 0.0159), increased abnormal seminiferous tubules (p = 0.0159), and histopathological abnormalities in the epididymis. In addition, chronic restraint stress induced epididymal tissue reorganization in the caput region, and altered spermatogenic stages. There was a reduction of relative empty vesicle weight (p = 0.0317) and prostate (p = 0.0079). Sperm counts were decreased in the testis (p = 0.0317), in the caput /corpus of the epididymis (p = 0.0285) and cauda (p = 0.0159). These findings suggest that chronic stress can adversely affect male reproductive parameters, suggesting a vulnerability in the epigenetic programming of sperm to stress.