[Mechanism of protective effect of resveratrol on poor ovarian response in mice]

This study aims to investigate the therapeutic effects and potential mechanisms of resveratrol(Res) on poor ovarian response(POR) in mice. The common target genes shared by Res and POR were predicted by network pharmacology, used for Gene Ontology(GO) annotation and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment, and then validated by animal experiments. The mice with regular estrous cycle after screening were randomized into normal, POR, and low-and high-dose(20 and 40 mg·kg~(-1), respectively) Res groups. The normal group was administrated with an equal volume of 0.9% sodium chloride solution by gavage, and the mice in other groups with tripterygium glycosides suspension(50 mg·kg~(-1)) by gavage for 2 weeks. After the modeling, the mice in low-and high-dose Res groups were treated with Res by gavage for 2 weeks, and the mice in normal and POR groups with an equal volume of 0.9% sodium chloride solution by gavage. Ovulation induction and sample collection were carried out on the day following the end of treatment. Vaginal smears were collected for observation of the changes in the estrous cycle, the counting of retrieved oocytes, and the measurement of ovarian wet weight and ovarian index. The enzyme-linked immunosorbent assay(ELISA) was employed to measure the levels of anti-mullerian hormone(AMH), follicle-stimulating hormone(FSH), estradiol(E_2), and luteinizing hormone(LH) in the serum. The ovarian tissue morphology and granulosa cell apoptosis were observed by hematoxylin-eosin(HE) staining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling(TUNEL), respectively. Western blot was employed to determine the protein levels of phosphatidylinositol 3-kinase(PI3K), protein kinase B(AKT), forkhead box O(FOXO) 3a, hypoxia-inducible factor(HIF)-1α, B-cell lymphoma-2(Bcl-2), and Bcl-2-associated X protein(Bax). A total of 222 common targets shared by Res and POR were collected. GO annotation indicated that these targets were mainly involved in oxidative stress response. KEGG enrichment analysis revealed that Res can intervene in POR via PI3K/AKT, HIF-1, and FOXO signaling pathways. Animal experiments showed that the model group had higher rate of estrous cycle disorders, lower number and poorer morphology of normally developed follicles at all levels, more atretic follicles, higher apoptosis of ovarian granulosa cells, lower number of retrieved oocytes, lower ovarian wet weight and ovarian index, higher serum levels of FSH and LH, lower levels of AMH and E_2, higher expression levels of HIF-1α, FOXO3a and Bax, and lower expression levels of PI3K, AKT, and Bcl-2 in the ovarian tissue than the normal group. Compared with the POR group, low-and high-dose Res decreased the rate of estrous cycle disorders, improved the follicle number and morphology, reduced atretic follicles, promoted the apoptosis of ovarian granulosa cells, increased retrieved oocytes, ovarian wet weight and ovarian index, and lowered serum FSH and LH levels. Moreover, Res down-regulated the expression levels of HIF-1α, FOXO3a and Bax, and up-regulated the expression levels of PI3K, AKT and Bcl-2 in the ovarian tissue. In summary, Res can inhibit apoptosis and mitigate poor ovarian response in mice by regulating the PI3K/AKT/FOXO3a and HIF-1α pathways.