Objective To explore the mechanism by which Sestrin2(SESN2)regulates autophagy activity of chondrocytes by mediating mammalian rapamycin target protein complex 1(mTORC1)signaling pathway.Methods The normal chondrocytes were treated with interleukin-1 β(IL-1β)to establish an osteoarthritis(OA)chondrocyte model,which was divided into the control group and the IL-1 β-treated group.Real-time quantitative PCR(qPCR)and Western blot were used to detect the expression levels of matrix metalloproteinase 13(MMP13),type Ⅱ collagen(COL2A1)and SESN2 in the two groups.The cell models of the chondrocyte overexpression SESN2 group and knockdown SESN2 group were obtained via cell transfection technology,and the expression levels of SESN2 in each group were detected by qPCR while those of SESN2,MMP13,COL2A1,mTORC1 pathway-related proteins and autophagy-related proteins in each group were detected by Western blot.The effects of SESN2 on cell proliferation and migration were detected by CCK-8 and cell scratch assay.Results(1)The expression level of MMP13 in the IL-1 β-treated group was significantly up-regulated,while the expression levels of COL2A1 and SESN2 were significantly decreased.(2)Compared with the control group,the expressions of p-mTORC1,ribosomal protein S6 kinase 1(S6K1),and MMP13 protein in OA chondrocytes in the overexpression group were significantly down-regulated,while the expressions of adenosine 5'-monophosphate(AMP)-activated protein kinase(AMPK)and chondroprotective gene COL2A1 were significantly increased,and the expression level of Beclin-1 and the ratio of microtubule associated protein 1 light chain 3-Ⅱ(LC3-Ⅱ)/(LC3-Ⅰ)were increased.Meanwhile,overexpression of SESN2 could up-regulate the proliferation and migration of chondrocytes,but the results were opposite after knockdown of SESN2.Conclusion SESN2 can enhance autophagy,proliferation and migration of chondrocytes by inhibiting mTORC1 pathway,which has provided data for revealing the pathogenesis of OA and exploring new therapeutic methods.