Abstract： Objective To explore the protective effect of bone marrow mesenchymal stem cells (MSC) on diabetic myocardium and anoxic pre-conditioning (AP).Methods Eight-week-- old male Sprague-Dawley rats were given with a single intraperitoneal injection of streptozotocin (STZ) (60 mg/kg)to induce diabetes mellitus (DM).Donor rats were 8-week-old male Sprague - Dawley rats.Before transplantation,MSC were incubated in CM-DiI at a concentration of 2 μg/mL for 20 min.AP-MSC were exposed to 3 hours of anoxia.At 4 months after STZ injection,diabetic rats were randomly given with an intramyocardial injection of one of the followings:150 μL of Dulbecco's modified Eagle's medium ( DMEM),5 ×106 MSC/150 μL,or 5 × 106 AP - MSC/150 μL (n =10 for each group).Three months after STZ injection and 2 weeks after transplantation,we evaluated the cardiac function by echocardiography,and also evaluated the cardiac conditions by alkaline phosphatase staining,western blot analysis for apoptosis related proteins and signal pathways.Results MSC,especially AP- MSC increased fractional shortening (FS) of diabetic heart (P ＜0.01 vs DMEM respectively).AP-MSC greatly increased the capillary density of diabetic myocardium (P ＜0.01 vs DMEM and MSC group respectively).AP-MSC are anti-apoptotic in the rat DCM model,possibly mediated through cardiac upregulation of Bcl-2/Bax ratio ( P ＜ 0.05 ) and inhibiting the expression and activation of caspase - 3 ( P ＜ 0.01 ).Conclusions Intramyocardial transplantation of APMSC has a protective effect on diabetic cardiomyopathy.