Therapeutic potential of quercetin in an animal model of PCOS: Possible involvement of AMPK/SIRT-1 axis.

Polycystic ovary syndrome is a common endocrine disorder worldwide. Recently, quercetin has been extensively investigated as a therapeutic option in patients with PCOS. Therefore, this study aimed to investigate the mechanisms underlying quercetin's positive effects by modulating key components of energy homeostasis and adipose tissue hormones in rats with letrozole-induced PCOS. Eighteen female Wistar rats were divided into three groups including control group (received carboxy methylcellulose (CMC 0.5%)), letrozole-induced PCOS ± quercetin group (received 1 mg/kg letrozole in CMC 0.5%), and letrozole-induced PCOS +/+ quercetin group (received same dose of letrozole + 100 mg/kg quercetin in CMC 0.5%). The estrous cycle, biochemical and hormonal parameters, as well as insulin resistance (IR) were evaluated in all groups. Western blotting was used to assess the expression levels of sirtuin-1 (SIRT-1), 5' AMP-activated protein kinase (AMPK), and adiponectin in target tissues of rats. The expression levels of visfatin and resistin were also evaluated through Real-time polymerase chain reaction (PCR). Treatment with quercetin improved the PCOS related disturbances in estrous cycle, lipid profile, serum levels of testosterone, estradiol and progesterone, and IR. Besides, the expression levels of AMPK and SIRT-1 in ovarian tissue were upregulated in the rats which received quercetin. Quercetin also reversed the PCOS-induced alteration in adipose tissue levels of adiponectin, visfatin, and resistin. Modulation of energy homeostasis through key components involved in this axis, as well as regulation of hormones releasing from adipose tissue may be the main underlying mechanisms for positive effects of quercetin in PCOS.