Objective       To determine the effect of transforming growth factor beta2 (TGF-β2) on histone acetylation of myocardial cell strain H9C2 and its role in regulating the expression of cardiac development-related transcription factors.       Methods       H9C2 cells were cultured and then treated with TGF-β2 at concentrations of 1.25

2.5

5

10 or 20 μg/L. Cell morphology was observed by inverted phase contrast microscopy (IPCM)

and cell counting was carried out at 12

24

48 and 72 h after treatment to draw the growth curve. Quantitative real-time PCR assay was used to select suitable intervention concentration of TGF-β2 by comparing the mRNA levels of Mef2c and GATA4. Expression of acetylated histone H3 (acH3) was assessed by Western blot assays. Histone Acetylase (HATs) Activity Colorimetric Assay Kit was used to measure the level of HATs activities. And

chromatin immunoprecipitation (ChIP) real-time PCR was employed to measure the level of acH3 in promoter regions of Mef2c and GATA4.        Results        TGF-β2  enhanced the proliferation in H9C2 cells（P0.05）. After TGF-β2 treatment

the mRNA expression of Mef2c and GATA4 was elevated in a dose-dependent manner

and then reached peak at a dose of 5 μg/L with an increase by 1.8 folds and 2.3 folds

respectively（P0.05）. The acetylation level of histone H3 increased by 4-fold (P0.05)

meanwhile

the HATs activity increased by 1.34-fold （P0.05）. TGF-β2 treatment resulted in the expression level of acH3 enhanced by 2.56- and 2.16-fold respectively in the promoter regions of Mef2c and GATA4 （P0.05）.        Conclusion       TGF-β2 at a dose of 5 μg/L promotes the proliferation in H9C2 cells

and up-regulates the expression of Mef2c and GATA4

which might be through improving the acetylation of histone H3.