[Effects of acupuncture on the hypothalamic-pituitary-ovarian axis and FSH/cAMP signaling pathway in aged rats].

To explore the mechanism of acupuncture on improving ovarian hypofunction in aged rats from two perspectives: the overall regulation of the hypothalamic-pituitary-ovarian (HPO) axis and the local ovarian follicle stimulating hormone (FSH)/cyclic adenosine monophosphate (cAMP) signaling pathway. Six 3-month-old female SPF-grade Sprague-Dawley (SD) rats were selected as the blank group. Another twelve 9-month-old female SD rats were randomly divided into a model group and an acupuncture group, with six rats in each. The acupuncture group received acupuncture at "Baihui" (GV20), "Guanyuan" (CV4), and bilateral "Ciliao" (BL32) for 20 min per session, once every other day, for a total of 10 sessions. Vaginal smear tests were performed daily to observe the estrous cycle of the rats. Ovarian morphology was observed using HE staining, and follicles at various stages were counted. ELISA was used to detect levels of serum FSH, luteinizing hormone (LH), estradiol (E2), anti-müllerian hormone (AMH), hypothalamic gonadotropin-releasing hormone (GnRH), pituitary FSH and LH, and ovarian cAMP. Immunohistochemistry and Western blot were used to detect the protein expression of ovarian cAMP protein kinase catalytic subunit, FSH receptor (FSHR), and P450. Real-time quantitative PCR was used to measure mRNA expression levels of FSHR and P450 in ovarian tissue. Compared with the blank group, the model group showed an increased rate of estrous cycle disorder (P<0.01), reduced granulosa cell layers with blurred boundaries and disordered arrangement, decreased numbers of developing follicles at all stages, and increased numbers of atretic follicles (P<0.01); the serum levels of FSH and LH were increased (P<0.01), while E2 and AMH levels were decreased (P<0.01); the hypothalamic GnRH and pituitary FSH and LH levels were elevated (P<0.01), and ovarian cAMP level was decreased (P<0.01); the positive expression and protein expression of ovarian P450, cAMP protein kinase catalytic subunit, and FSHR were reduced (P<0.01), and ovarian FSHR and P450 mRNA expression was decreased (P<0.01). Compared with the model group, the acupuncture group showed a reduced rate of estrous cycle disorder (P<0.01), clear granulosa cell margins, increased numbers of primordial and secondary follicles, and decreased numbers of atretic follicles (P<0.01); the serum FSH and LH levels were decreased (P<0.01, P<0.05), while E2 and AMH levels were increased (P<0.05, P<0.01); the hypothalamic GnRH and pituitary FSH and LH levels were decreased (P<0.01, P<0.05), and ovarian cAMP level was increased (P<0.01); the positive expression and protein expression of ovarian P450, cAMP protein kinase catalytic subunit, and FSHR were elevated (P<0.01), and ovarian FSHR and P450 mRNA expression was increased (P<0.01). Acupuncture could delay ovarian hypofunction in aged rats, possibly through regulating the HPO axis and the FSH/cAMP signaling pathway.