Abstract: Objective: To investigate the protective effect of ginseng extract on the lipotoxic cardiomyocyte injury induced by palmitic acid (PA),and to clarify its possible mechanism. Methods: The H9c2 cells were cultured in vitro.The levels of lipid droplets in H9c2 cells after treated with different concentrations(100,200,and 1 000 μmol·L^-1) of PA were detected by oil red O staining,the survival rates of H9c2 cells after treated with different concentrations(200,400,600,and 800 μmol·L^-1) of PA were detected by MTT assay,and the apoptotic rates of H9c2 cells after treated with different concentrations(200,400,600,and 800 μmol·L^-1) of PA were detected by flow cytometry.The concentration of PA and the action time were screened;according to the screening results,the PA concentrations were selected as 100 and 200 μmol·L^-1,and the action time was 24 h.The H9c2 cells were randomly divided into control group,PA group (100 or 200 μmol·L^-1) and and different concentrations (0.2,2.0,and 20.0 mg·L^-1)of ginseng extract groups.Flow cytometry and FITC-Annexin Ⅴ/PI double staining were used to detect the apoptotic rates of the H9c2 cells in various groups,JC-1 staining was used to detect the levels of mitochondrial membrane potential (MMP) in the H9c2 cells in various groups,and DCFH-DA staining was used to detect the levels of intracellular reactive oxygen species (ROS) in the H9c2 cells in various groups. Results: Compared with control group,the levels of lipid droplets in the H9c2 cells in 100,200, and 1 000 μmol·L^-1 PA groups were increased significantly (P<0.01).Compared with control group,the survival rates of the H9c2 cells in 200,400,600,and 800 mmol·L^-1 PA groups were decreased (P<0.01),and the apoptotic rates of the H9c2 cells in 200,400,600,and 800 mmol·L^-1 PA groups were increased(P<0.01).After treated with different concentrations of ginseng extract for 24 h,compared with 100 or 200 μmol·L^-1 PA groups,the lipid levels of the H9c2 cells in 2.0 and 20.0 mg·L^-1 ginseng extract groups were decreased(P<0.01),the apoptotic rates were decreased(P<0.01),and the levels of ROS were decreased (P<0.01); the levels of MMP in the H9c2 cells in different concentrations of ginseng extract groups were decreased (P<0.01). Conclusion: Ginseng extract can inhibit the apoptosis of the cardiomyocytes induced by PA,and its mechanism may be related to the down-regulation of ROS and MMP levels in the H9c2 cells.

Key words: ginseng extract, lipidtoxicity, apoptosis, reactive oxygen species, mitochondrial membrane potential, palmitic acid