Abstract: 【Abstract】 Objective To investigate the effects of trimetazidine (TMZ) on the oxidative stress injury in adipose-derived mesenchymal stem cells (ADSCs). Methods ADSCs derived from adipose tissue of SD rats were characterized by flow cytometry and multiline age differentiation. ADSCs apoptosis was induced by H2O2 in vitro , Dirrerent concentration of TMZ (250 μmol/L, 500 μmol/L) was used to protect ADSCs from apoptosis. The morphological features of apoptotic ADSCs were analyzed by Hoechst 33342, mitochondrial potential and structure was analyzed by JC-1 staining and electron microscope, respectively. The apoptotic proteins were detected by Western blot. The effect of TMZ on antioxidant capacity of ADSCs was evaluated by detecting reactive oxygen species (ROS), superoxide dismutase (SOD), glutathione (GSH) and malondialdehyde (MDA). Results The isolated ADSCs expressed high levels of CD29 and CD90, low levels of CD34 and CD45 and no expression of CD31. ADSCs could be induced to adipocyte and osteoplastic cells. After being treated by H2O2, ADSCs displayed apoptosis characteristics with increased number of apoptotic cells, decreased mitochondrial transmembrane potential and damaged mitochondria. The expressions of apoptotic proteins, including Bax, Bad, and Caspase3, were dramatically increased compared to the controls; however, the anti-apoptotic protein Bcl2 was decreased. At the meantime, the contents of ROS and MDA were elevated, but the concentrations of SOD and GSH were reduced. The treatment of TMZ could partly reverse above negative impacts to ADSCs. Conclusion TMZ could improve the survival rate of ADSCs by enhancing anti-oxidant defense systems to remove excessive ROS and regulating the expression of protective protein.