Ameliorative effects and mechanisms of Inonotus hispidus on PCOS via regulation of gut microbiota-ovarian metabolism axis and ferroptosis inhibition.

Polycystic ovary syndrome (PCOS) is a prevalent endocrine metabolic disorder with limited therapeutic options. This study investigated the ameliorative effects and underlying mechanisms of the water extract of Inonotus hispidus (WE) on PCOS in a testosterone propionate induced rat model. The results of this study indicate that WE significantly reduced abnormal body weight gain, restored disrupted estrous cycles, and ameliorated ovarian cystic degeneration, interstitial fibrosis, and hepatic steatosis in PCOS rats. It also down-regulated serum estradiol, testosterone, luteinizing hormone levels and the LH/FSH ratio, and normalized amino acid metabolism related enzyme activity. Metabolomic analysis revealed WE reversed ovarian metabolic dysregulation, enriching pathways like amino acid and bile acid metabolism. 16S rRNA sequencing showed WE reshaped gut microbiota dysbiosis, restoring α/β diversity and correcting the Firmicutes/Bacteroidetes ratio. Western blot analysis confirmed that WE inhibited ovarian cell ferroptosis by downregulating ACSL4, HIF-1α, and TFRC expression, while upregulating GPX4, and normalized the expression of amino acid metabolism-related proteins. This study demonstrates that WE improves ovarian function in rats by inhibiting ferroptosis, regulating ovarian amino acid/bile acid metabolism, and reshaping the gut microbiota, thereby exerting therapeutic effects on PCOS. This study provides a theoretical basis for the preclinical research and future clinical translation of Inonotus hispidus.