Preventive Effect of Fisetin on Follicular Granulosa Cells Senescence via Attenuating Oxidative Stress and Upregulating the Wnt/β-Catenin Signaling Pathway.

Oxidative stress-mediated dysfunction of granulosa cells (GCs) is recognized as a pivotal driver of prehierarchical follicular atresia in poultry, contributing substantially to the reduced egg production in aged laying hens. Here, we investigated the protective effects of the natural flavonol, fisetin, on aged chicken follicular GCs. A D-galactose (D-gal)-induced aging model of GCs was established to evaluate the protective role of fisetin against cellular senescence. Small yellow follicles (SYFs) from 580-day-old hens were cultured with fisetin for 72 h to verify its ameliorative effect on naturally aged follicles. Fisetin reduced the typical characteristic of senescence in D-gal-induced GCs, as reflected by decreased senescence-associated β-galactosidase (SA-β-gal) activity and increased expression of proliferation-related proteins, including cyclin D1 (CCND1), cyclin-dependent kinase 2 (CDK2), cyclin-dependent kinase 1 (CDK1), and Cyclin B1. Furthermore, fisetin enhanced the activity of antioxidant enzymes by activating the Nrf2/HO-1 signaling pathways, while attenuating mitochondrial dysfunction and promoting ATP production in senescent GCs. Additionally, fisetin significantly promoted nuclear translocation of β-catenin, and suppressed the expression of senescence marker proteins p53 and p21, thereby alleviating cell cycle arrest in D-gal-induced senescent GCs. Simultaneous inhibition of Nrf2/HO-1 and β-catenin signaling also abolished the beneficial effects of fisetin on oxidative stress and cell proliferation in naturally senescent follicles. These findings indicate that fisetin prevents follicular atresia by suppressing GCs oxidative damage and improving cell cycle arrest via activating the Nrf2/HO-1 and Wnt/β-catenin signaling pathways.