Abstract: Objective To investigate the effect of autophagy on the apoptosis of H9C2 cardiomyocytes. Methods H9C2 cardiomyocytes were treated with different concentrations of high glucose and high lipids(HGHL) at different time points. The surface area of cardiomyocytes was measured after HE staining. The cell viability and apoptotic rate were measured by flow cytometry. So we can determine the optimal concentration and time of myocardial cell hypertrophy and apoptosis. Western blot was used to detect the expression levels of LC3II, p62, Beclin-1,LAMP2 and cleaved caspase-3. Results After treated with HGHL, the cells appeared hypertrophy in a concentration-and time-dependent manner, the cell hypertrophy was most obvious under the condition of HGHL(500 μmol/L,36 h)(P<0.001). Cell apoptosis was increased in a concentration-and time-dependent manner, the apoptotic rate was nearly 50 % under the condition of HGHL(500 μmol/L,36 h)(P<0.001). After treatment with HGHL for 24 h, compared with the control group, the expression of LC3II was very significantly increased（P﹤0.01）, the expression of Beclin-1 and LAMP2 were significantly decreased(P﹤0.05), but the expression of p62 was significantly increased（P﹤0.01）. Compared with the control group and the intervention group, the expression of cleaved caspase-3 was significantly increased (P<0.01) after 1 h of chloroquine pretreatment . Conclusions HGHL could induce H9C2 cardiomyocytes hypertrophy and promote H9C2 cardiomyocytes apoptosis in a concentration-and time-dependent manner. HGHL could inhibit autophagy formation and degradation of H9C2 cardiomyocytes at the same time, leading to abnormal autophagy accumulation of cardiomyocytes, and promote apoptosis, suggesting that inhibition of autophagy may be an important reason to promote apoptosis.

Key words: Diabetic cardiomyopathy, Myocardial Hypertrophy, Autophagic, Apoptotic, Cardiomyocytes