Abstract
Objective To investigate the effect of homocysteine (Hcy) on the cardiomyocytes cultured in vitro, and to analyze the role of folic acid in DNA methylation to explore the protective effect and mechanism of folic acid during Hcy exposure of H9C2 cardiomyocytes. Methods H9C2 cells were treated with Hcy at different concentrations (0, 0.5, 1, 2) mmol/L for 24 hours. Cell viability was tested by CCK-8 assay. The apoptosis was detected by flow cytometry. H9C2 cells were divided into 2 mmol/L Hcy group, 0.1 mmol/L folic acid combined with 2 mmol/L Hcy group, 0.1 mmol/L folic acid group and DMSO control group. The above corresponding treatment lasted 24 hours. Then we detected the cell viability and apoptosis. The total DNA methylation level was determined by MethylFlash ELISA kit. DNMT1, DNMT3a, DNMT3b mRNA and protein expression were detected by real-time quantitative PCR and Western blot analysis. Results The number of H9C2 cells treated with different concentrations of Hcy for 24 hours decreased with the increase of Hcy concentration. Compared with the control group, the activity and apoptosis of the cells in the 2 mmol/L Hcy treatment group were reduced, and the number of cells in the folic acid combined with Hcy treatment group was significantly higher than that in the Hcy treatment group. Compared with the other groups, the total apoptosis rate of Hcy treatment group increased, methylation level decreased significantly, and the level of DNA methylation increased in the folic acid combined with Hcy treatment group. The level of DNMT1 mRNA significantly increased only in the folic acid treatment group, and the levels of DNMT1, DNMT3a and DNMT3b were not significantly changed. Conclusion Folic acid can relieve the damage of Hcy to myocardial cells by DNA methylation.
