中文摘要：

目的探讨转化生长因子-β2（transforming growth factorbeta2，TGF-β2）对心肌细胞H9C2转录因子Mef2c和GATA4的影响及其与组蛋白H3乙酰化的关系。方法比较TGF—β2对细胞生长的影响。利用Real-timePCR检测心肌细胞的心脏相关转录因子Met2c和GATA4mRNA的相对表达量，筛选合适的TGF-132干预浓度。采用Westernblot检测心肌细胞乙酰化组蛋白H3（acetylatedhistoneH3，acH3）的表达差异。染色质免疫共沉淀（chromatinimmunoprecipitation，CHIP）Real—timePCR检测Mef2c和GATA4启动子区与acH3结合DNA的相对表达水平。比色分析法检测TGF-β2对心肌细胞的总体组蛋白乙酰化酶（HATs）活性的影响。结果（1）TGF-β2干预组相对于对照组心肌细胞的增殖能力增强（P〈0．05）。②心肌细胞的心脏相关转录因子Mef2c和GATA4mRNA的相对表达量随着TGF—β2浓度的升高呈现先升高后降低的趋势，在5μg／L的浓度时均达到最高，Mef2cmRNA相对表达量是对照组的1．8倍，GATA4mRNA是对照组的2．3倍（P〈0．05）。（3）TGF-β2干预72h后acH3蛋白表达量是对照组的4倍（P〈0．05），HATs活性是对照组的1．34倍（P〈0．05）。④TGF-β2干预组Mef2c和GATA4启动子区组蛋白H3的乙酰化水平分别是对照组的2．56和2．16倍（P〈0．05）。结论5μg/LTGF-β2可以促进心肌细胞H9C2的分裂与增殖，并上调心脏相关转录因子Mef2c和GATA4的表达，组蛋白H3乙酰化水平的升高可能是Mef2c和GATA4表达上调的机制之一。

英文摘要：

Objective To determine the effect of transforming growth factor beta2 （TGF-[32） on histone acetylation of myocardial cell strain H9C2 and its role in regulating the expression of cardiac develop- ment-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-[32 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 （ P 〈 0.05 ）. After TGF-β2 treatment, the mRNA expression of Mef2e 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 （ P 〈 0.05 ）. The acetylation level of histone H3 increased by 4-fold （ P 〈 0. 05 ）, meanwhile, the HATs activity increased by 1.34-fold （ P 〈 0. 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 （P 〈 0. 05）. Conclusion and up-regulates the expression of histone H3. TGF-152 at a dose of 5μg/L promotes the proliferation in H9C2 cells, Mef2c and GATA4, which might be through improving the acetylation of