Rhamnocitrin Ameliorates Ovarian Fibrosis Via PPARγ/TGF-β1/Smad Pathway to Repair Ovarian Function in Polycystic Ovary Syndrome Rats Running Title：rhamnocitrin Ameliorates Ovarian Fibrosis in Polycystic Ovary Syndrome Rats

Background: Polycystic ovary syndrome (PCOS) is one of the major endocrine disorders in women, characterized by androgen excess, chronic anovulation and ovarian fibrosis. Rhamnocitrin is an herbal bioactive flavonoid that has anti-inflammation and antioxidant effects. We intended to investigate the impacts of Rhamnocitrin on PCOS-induced ovarian fibrosis and its underlying mechanisms. Methods: : Dehydroepiandrosterone (DHEA) induced-PCOS rats were treated with Rhamnocitrin. HE staining was performed to detect ovarian histological features. Ovarian fibrosis was evaluated by Sirius Red and Masson staining. Vaginal smear was examined to exhibit estrus cycle stage and vaginal cornification. The serum hormone levels of FSH, LH, E2 and T were measured with ELISA. The related mRNAs and proteins of fibrosis factors and PPARγ/TGF-β1/Smad2 signaling were detected by RT-qPCR and western blot. The weights of rat bodies and ovaries were recorded. PPARγ inhibitor T0070907 and its agonist GW1929 were employed for the mechanistic investigation. Results: : The corpus luteum and follicles were increased and irregular estrous cycle was restored after Rhamnocitrin treatment in PCOS rats. Rhamnocitrin inhibited ovarian fibrosis and down-regulated the expressions of fibrotic factors. Rhamnocitrin reduced the increased levels of LH, E2, and T, and elevated the decreased FSH level in PCOS rats. Besides, Rhamnocitrin elevated the down-regulated PPARγ, and suppressed the up-regulated TGF-β1 and p-Smad2 expressions induced by PCOS. These effects of Rhamnocitrin on PCOS rats could be antagonized by T0070907, whereas GW1929 markedly mimics the functions of Rhamnocitrin. Conclusions: : Rhamnocitrin ameliorates ovarian fibrosis in PCOS rats through regulation PPARγ/TGF-β1/Smad2pathway, suggesting it can be a potentially effective therapeutic candidate for PCOS treatment.