Quercetin ameliorates cyclophosphamide-induced premature ovarian insufficiency by modulating SIRT1/HIF-1α pathway

Premature ovarian insufficiency (POI) is characterized by complex etiologies and currently lacks effective treatments, posing significant threats to women’s physical and psychological health. Quercetin (QUE), a bioactive flavonoid inherent in traditional herbs such as Flos Sophorae and Cuscuta chinensis, demonstrates potent redox-modulating and anti-senescence capacities. This investigation validates its therapeutic efficacy against POI, specifically elucidating granulosa cell-centric mechanisms. POI mouse models and injury models of the KGN (human ovarian granulosa cell line) were induced through the administration of cyclophosphamide (CTX). Subsequently, these models were treated with drugs such as QUE. Morphological changes in the ovaries of the mice were observed, and vaginal smears were conducted to monitor the estrus cycles and patterns of the mice. ELISA was employed to detect sex hormone levels in various mouse groups, while Hematoxylin-eosin (H&E) staining was utilized to assess the status of ovarian follicles at different stages. Moving forward, immunohistochemical analysis and Western blot were conducted to detect the expression levels of Sirtuin 1 (SIRT1), Hypoxia-Inducible Factor 1 Alpha (HIF-1α), and other apoptosis-related proteins. Ultimately, methods such as Terminal deoxynucleotidyl transferase dUTP Nick-End Labeling (TUNEL) assay, β-galactosidase staining, flow cytometry for apoptosis detection, and 5-Ethynyl-2′-deoxyuridine (EdU) assay were utilized to evaluate the apoptosis, senescence, and proliferation of mouse ovarian tissues and human ovarian granulosa cells KGN. QUE alleviated CTX-induced ovarian atrophy and follicular atresia by upregulating SIRT1 expression. Furthermore, QUE partially restored estrous cyclicity, normalized sex hormone levels, and improved follicular counts through SIRT1/HIF-1α modulation. Concurrently, QUE suppressed apoptosis in both murine and human granulosa cells via the SIRT1/HIF-1α pathway. Our findings demonstrate that QUE enhances ovarian reserve by inhibiting granulosa cells apoptosis via SIRT1/HIF-1α signaling, highlighting its therapeutic potential for POI management.