β-Sitosterol Preconditioning Enhances the Resistance of BMSCs and Chondrocyte to Oxidative Stress and Promotes Cartilage Repair in Osteoarthritis

I. Background: Osteoarthritis (OA) is a joint disorder that severely affects patients' mobility, overall health, and ability to perform daily activities. Despite advancements in therapeutic strategies, stem cell-based therapies for OA still face challenges, particularly in enhancing the antioxidative capacity of stem cells to improve therapeutic outcomes. Therefore, this study aimed to explore the potential of β-sitosterol in this context. II. Methods: This study evaluated the protective effects of β-sitosterol on bone marrow-derived mesenchymal stem cells (BMSCs) and chondrocytes under oxidative stress conditions and assessed its potential in promoting cartilage repair in a rabbit OA model. Cell viability, gene expression, oxidative stress markers, and mitochondrial function were examined. In vivo therapeutic effects were evaluated through histological and immunohistochemical analyses. III. Results: The results revealed that β-sitosterol significantly enhanced BMSC viability, upregulated the expression of Col2a1 and aggrecan, while inhibiting MMP13 expression. Furthermore, β-sitosterol effectively alleviated oxidative stress and preserved mitochondrial function in BMSCs. Notably, BMSCs pretreated with β-Sitosterol exhibited a higher potential for facilitating cartilage regeneration in the OA model, as evidence by histopathological analysis. IV. Conclusions: These findings suggest that β-sitosterol possesses significant antioxidative and chondroprotective properties, which enhance the therapeutic efficacy of BMSCs in addressing OA-related cartilage damage.