乙型肝炎病毒对肝内TGF-β1/Smads信号通路的作用

 目的：探讨乙型肝炎病毒（HBV）对肝内TGF-β1蛋白表达及Smads信号通路的作用，为制定慢性乙肝肝纤维化临床治疗策略提供理论依据。方法：(1)运用免疫组化PV-6000法检测对照组和慢性乙肝组肝组织中TGF-β1、HBsAg和HBcAg的表达，并采用荧光定量PCR法测定慢性乙肝患者血清HBV DNA含量。(2)应用体外细胞培养技术培养HBV刺激的人肝星状细胞系LX-2细胞，Western blotting方法测定其细胞内TGF-β1、Smad3和Smad7的蛋白表达。结果：(1)慢性乙肝组肝组织内TGF-β1的表达高于对照组（P＜0.01）；肝内TGF-β1表达水平与血清HBV DNA含量呈正相关（P＜0.01），且HBcAg阳性肝组织水平较高（P＜0.01）。(2)体外细胞学实验中，HBV刺激组LX-2细胞内TGF-β1和Smad3蛋白含量高于对照组和HBV+抗-TGF-β1组（P＜0.01）；Smad7蛋白表达差异无统计学意义（P>0.05）。结论：(1)TGF-β1在慢性乙肝患者肝组织中的表达与血清HBV DNA含量及肝内HBcAg的表达有关。(2)在TGF-β1/Smads信号通路中，HBV致纤维化作用机制以Smad3的正性调控为主，Smad7的作用不明显。

Role of hepatitis B virus in intrahepatic TGF-β1/Smads signaling pathway

AIM:To explore the effects of hepatitis B virus (HBV) on intrahepatic expression of transforming growth factor β1（TGF-β1） and Smads. METHODS:The expression of intrahepatic TGF-β1, HBsAg and HBcAg in control group and chronic hepatitis B (CHB) group was detected by immunohistochemical method.The serum HBV DNA content was determined by real-time PCR. The role of HBV in the expression of TGF-β1, Smad3 and Smad7 in human hepatic stellate cell line LX-2 in vitro was observed by cell culture and Western blotting. RESULTS:The average score of intrahepatic TGF-β1 expression in CHB group was higher than that in control group. With the increase in serum HBV DNA content, intrahepatic TGF-β1 expression was also enhanced. In the HBcAg positive hepatic tissue, there was higher TGF-β1 expression than that in the liver tissue of HBcAg negative. Compared with control group and HBV+anti-TGF-β1 group, HBV caused increased expression of TGF-β1 and Smad3 in HBV group in vitro. No difference of Smad7 protein among control group, HBV group and HBV+anti-TGF-β1 group was observed. CONCLUSION: The expression of intrahepatic TGF-β1 is related to serum HBV DNA and hepatocellular HBcAg in the patients with CHB. HBV-induced liver fibrosis mainly relies on positive regulatory mechanisms of Smad3,and the negative regulation by Smad7 almost does not function.