肝硬化组织中p16^(INK4a)和Rb的基因甲基化状态和蛋白表达

Gene methylation status and protein expression of p16^(INK4a) and Rb in cirrhosis liver tissue

目的:探讨肝硬化组织中p16INK4a和视网膜母细胞瘤易感基因(Rb基因)启动子区域的甲基化状态与其蛋白的表达的关系。方法:分别采用PCR和免疫组织化学方法测定65例肝硬化患者和20例正常人肝组织中p16INK4a和Rb启动子区域甲基化状况和蛋白的表达。结果:20例正常肝组织(对照组肝组织)中均未检测到p16INK4a和Rb甲基化异常,肝硬化组肝组织中p16INK4a和Rb基因甲基化率分别为40.0%(26/65)和36.9%(24/65);p16INK4a和Rb蛋白表达的积分光密度(IOD)在正常肝组织为225.7±27.4和254.7±34.8,在肝硬化组肝组织中为32.4±7.5和45.2±6.4,差异均有统计学意义(均P<0.05)。结论:肝硬化组织中存在p16INK4a和Rb异常甲基化和p16INK4a和Rb蛋白的表达降低,由此导致的细胞周期失控可能参与了肝硬化的发生发展过程。

Objective： To investigate the methylation status at the promoter region of the p16^INK4a and retinoblastoma （Rb） gene in cirrhosis liver tissue and its relations with the protein expression of the two genes. Methods： The DNA methylation status and protein expression of p16^INK4a and Rb in the liver tissues from 65 patients with cirrhosis and 20 healthy subjects were detected by PCR and immunohistochemical staining, respectively. Results： No abnormal methylation ofp p16^INK4a and Rb gene was detected in any of the 20 cases of normal liver tissue, while the methylation ratios of the p16^INK4a and Rb gene in the cirrhosis liver tissue were 40% （26/65） and 36.9% （24/65）, respectively. The integrated optical densities （IOD） of the p16^INK4a and Rb protein expression in the normal liver tissue were 225.7±27.4 and 254.7±34.8, while those in the cirrhosis liver tissue were 32.4±7.5 and 45.2±6.4, respectively, and both differences had statistical significance （both P〈0.05）. Conclusion： Cirrhosis liver tissue has abnormal methylation of p16^INK4a and Rb gene and decreased expression of p16^INK4a and Rb protein, and the resulting loss of cell cycle control may be involved in the occurrence and development of liver cirrhosis.