Pre-gestational restraint stress affects reproductive outcomes in adult rats by modulating ovarian and uterine function

Abstract

The impact of gestational stress on reproductive outcomes is well-established, but the effects of pre-gestational stress remain inconclusive. Using female Wistar rats, we demonstrated that pre-gestational stress negatively affects fertility and pregnancy outcomes. The rats were subjected to restraint stress (RS) for 15 days, with 3 h of stress each day, before mating. The RS group exhibited higher levels of corticosterone and prolactin, along with lower levels of adrenocorticotropic hormone (ACTH), indicating a successful stress model. Stressed rats showed reduced fertility and fecundity indices, longer conception times, and decreased levels of ovarian steroids, such as progesterone, testosterone, and estradiol. Additionally, the ovaries of the RS group had fewer antral follicles and more ovarian cysts. Elevated protein levels of cytochrome P450 side-chain cleavage enzyme (CYP11A1) and aromatase (CYP19A1), along with decreased levels of 17β-hydroxysteroid dehydrogenase (17β-HSD), indicating impaired ovarian steroidogenesis in stress exposed rats. In the RS group, there was a significant increase in proteins associated with folliculogenesis, specifically octamer-binding transcription factor 4 (OCT 4) and growth differentiation factor 9 (GDF 9). Additionally, proteins linked to ovulation, such as the prolactin receptor (PRLR), peroxisome proliferator-activated receptor-γ (PPAR-γ), and cyclooxygenase 2 (COX 2), were elevated. The increased levels of PRLR, progesterone receptor (PR), androgen receptor (AR), and estrogen receptor (ER) combined with heightened oxidative stress in the uteri of the RS group, suggest a potential disruption in uterine function. Overall, this research indicates that pre-gestational stress can significantly impact reproductive health by altering gonadotrophin and ovarian steroid dynamics in the female reproductive tract.