Nutlin-3

Osteoarthritis (OA) is a degenerative joint disease characterized by progressive destruction of articular cartilage. Isoquercitrin (ISO), a natural flavonoid, has well-documented anti-inflammatory and antioxidant properties. This study investigates the chondroprotective effect of ISO in OA, with a particular emphasis on its regulation of P53-mediated ferroptosis. In tert‑butyl hydroperoxide (TBHP)-induced chondrocytes, ISO treatment effectively ameliorated extracellular matrix (ECM) metabolic imbalance by upregulating the expression of COL2A1 and ACAN, while downregulating MMP13 and ADAMTS5. Concurrently, ISO reduced intracellular levels of reactive oxygen species (ROS), lipid peroxidation, and iron accumulation, as measured by fluorescent probes DCFH-DA, BODIPY 581/591 C11, and FerroOrange, respectively. Furthermore, ISO significantly suppressed P53 protein expression while enhancing the levels of SLC7A11 and GPX4, which were key regulators of ferroptosis resistance. Network pharmacology analysis, molecular docking, and cellular thermal shift assay (CETSA) collectively identified P53 as a direct molecular target of ISO. In vivo, daily administration of ISO markedly attenuated cartilage degeneration and ferroptotic damage in a rat model of OA induced by anterior cruciate ligament transection (ACLT), as confirmed by histopathological evaluation. Notably, these protective effects were partially reversed upon co-treatment with nutlin-3, a pharmacological activator of P53. Collectively, these findings demonstrate that ISO alleviates OA pathology by inhibiting P53-dependent ferroptosis, highlighting its potential as a dietary supplement for the prevention and management of OA.