中文摘要：

目的研究甜菜碱对人肝癌细胞HepG2内基因组范围DNA甲基化的影响。方法以浓度0．1、0．2、0．4mol／L甜菜碱作用于人肝癌细胞HepG224、48h后，通过高效毛细管电泳仪（HPcE）检测肿瘤细胞中DNA水解产物中5-甲基-2’-脱氧胞嘧啶（5-methyl-2’deoxycytidine，5mdC）水平，来检测甜菜碱对HepG2内基因组范围DNA甲基化表达的影响。结果随着甜菜碱的浓度增大，5mdC占总体胞嘧啶的峰面积的百分比也相应增大，且有剂量依赖性。结论甜菜碱作为甲基供体，促进HepG2细胞基因组范围DNA甲基化的表达，从而调控细胞周期抑制肿瘤的生长。

英文摘要：

Objective To study the effect of betaine on the DNA methylation in HepG2 genome. Methods After betaine at concentration of 0. 1, 0. 2, and 0.4 mol/mL was applied to HepG2 cells for 24 and 48 h, the level of 5-methyl-2-deoxycytidine （5 mdC） in the DNA hydrolytic product in the tumor cells was tested using HPCE. Results As the eoneentraion of betaine increased, the percentage of 5 mdC in the peak area of total cytidine also increased in a dosg-dependent manner. Conclusion As a methyl donor, betaine could promote the expression of DNA methylation in the genome of HepG2 cells, thus regulating the cell cycle of cells and inhibiting tumor growth.