Fisetin mitigates letrozole-induced polycystic ovarian syndrome in rats: crosstalk of AMPK/PI3K/AKT-mediated-Nrf2 antioxidant defense mechanism and the inflammasome NLRP3/NF-κB P65/IL-1β signaling pathways

Polycystic ovarian syndrome (PCOS) is a highly prevalent condition affecting reproductive-aged women, causing insulin resistance, hyperandrogenism, weight gain, and menstrual problems. The present study intended to investigate the potential role of fisetin (FT) in letrozole (LZ)–induced PCOS in adult female rats and the possible mechanism underlying its action. PCOS was induced by oral administration of LZ (1 mg/kg) for 21 days. Treated rats received FT (1.25 or 2.5 mg/kg) orally once daily for 14 consecutive days. Following the experimental duration, blood samples and ovary tissues were isolated and preserved for biochemical and histopathological examinations. The results revealed that LZ-induced PCOS led to significant abnormalities in sex hormones and metabolic parameters. Additionally, it initiated an inflammatory cascade, evidenced by activation of the NF-κB p65/IL-1β and AMPK/PI3K/AKT pathways, alongside downregulation of Nrf2 ovarian gene expression and NLRP3 inflammasome activity, which enhanced the production of proinflammatory cytokines. FT demonstrated its beneficial impacts by restoring hormonal disturbance and reversing the imbalanced metabolic parameters. Moreover, FT increased the mRNA of ovarian Nrf2 levels and suppressed the up-regulated inflammatory IL-1β/NF-κB p65 signaling pathway, consequently alleviating the elevated levels of ovarian NLRP3. The histopathological examination also confirmed that FT has a beneficial effect in ameliorating PCOS, consistent with the aforementioned parameters. Finally, the present results demonstrated that FT ameliorates LZ-induced PCOS through the intricate interplay between the AMPK/PI3K/AKT-mediated Nrf2 antioxidant defense mechanism and the regulation of the inflammasome NLRP3/NF-κB p65/IL-1β signaling pathways. Graphical abstract