Abstract
Osteoarthritis (OA) is a common age-related degenerative disease involving various pathological processes, among which apoptosis in chondrocyte and extracellular matrix (ECM) degradation are the main pathologies. Previous studies have shown that autophagy has a protective effect on apoptosis and ECM degradation in chondrocytes. Methyl gallate (MG) is a natural polyphenol from various medicinal and edible plants. Moreover, several studies have demonstrated that MG exerts multiple pharmacological effects in various diseases, including anti-inflammatory, antioxidant, and anti-apoptosis. Hence, in this study, we investigate the protective effect of MG on the pathological process of OA in cellular and mice OA model to elucidate the underlying molecular mechanism. In vitro, MG treatment inhibits the expression of pro-apoptotic proteins and promotes the expression of anti-apoptotic proteins under TBHP stimulation. Meanwhile, MG treatment promotes the expression of Collagen II and Aggrecan and inhibits the expression of matrix-degrading enzymes thrombospondin motifs 5 (ADAMTS5) and matrix metalloproteinase-13 (MMP13), which lead to ECM degradation. Furthermore, in terms of mechanism, MG treatment enhances autophagy by upregulating SIRT3 expression, and inhibition of autophagy could eliminate the protective effect of MG on chondrocytes in terms of anti-apoptosis and ECM synthesis. The protective effect of MG on OA has also been observed in mice OA model. In brief, our study suggests that MG could be a potential candidate for the treatment of OA.