• β-sitosterol enhances BMSC viability and upregulates chondrogenic markers (Col2a1, aggrecan) while suppressing MMP13, indicating chondroprotective effects.
• β-sitosterol alleviates oxidative stress and preserves mitochondrial function in BMSCs, addressing a key barrier to stem cell therapy efficacy in OA.
• BMSCs preconditioned with β-sitosterol show improved cartilage regeneration in a rabbit OA model, as confirmed by histopathological analysis.
• This study provides a novel strategy to enhance stem cell-based therapies for OA by leveraging the antioxidative properties of a natural compound.