肝纤维化过程中Toll样受体4在肝脏的表达分布及意义

目的动态观察大鼠肝纤维化过程中Toll样受体4（Toll-like receptor4,TLR4）蛋白在肝脏的表达,探讨TLR4与肝纤维化发生发展的关系。方法以四氯化碳皮下注射复制大鼠肝纤维化模型,设立正常对照组和模型1周组、2周组、4周组、6周组。常规HE染色和天狼猩红胶原染色观察肝脏病变;检测肝组织羟脯氨酸和血浆内毒素含量;免疫组化和Western blot检测TLR4在肝组织中的表达,检测α-SMA观察活化的肝星状细胞（HSCs）。结果与正常对照组比较,CCl4作用2周时,肝组织羟脯氨酸含量开始明显增多（P〈0.01）;模型组各组血浆内毒素含量呈梯度上升（P〈0.01）,且与肝组织羟脯氨酸含量呈显著正相关关系（P〈0.01）;CCl4作用1周后肝组织TLR4的表达即明显增强（P〈0.01）,4周时和6周时有所下降（与2周组相比,P〈0.05）,但仍高于正常对照组（P〈0.01）。TLR4阳性细胞包括枯否细胞、活化的HSCs及少量的肝细胞和内皮细胞。结论内毒素及其受体TLR4的改变可能在肝纤维化中起重要作用。

Expression,Distribution and Significance of TLR4 in the Liver in the Development of Hepatic Fibrosis

Objective To observe the dynamic expression patterns of TLR4 protein in the rat liver with chronic fibrogenesis,and to explore the relationship of TLR4 expression with the pathogenesis of hepatic fibrosis.Methods A model of hepatic fibrosis was established using carbon tetrachloride subcutaneous injections in rats.The rats were designed to normal control group and four model groups（1 week,2 week,4 week,6 week）.Liver tissue slides were stained with HE and sirius red to study the pathological changes in the livers.Hydroxyproline in liver tissues was measured,and plasma level of endotoxin was measured.Immunohistochemistry and Western blot were used to analyze the expression of TLR4 protein.The α-SMA was determined to observe the activation of HSCs.Results Compared with normal control group,hydroxyproline in liver tissues increased significantly from 2 week（P 0.01）.Plasma level of endotoxin increased significantly in each group（P 0.01）,and there was significant positive correlation with hydroxyproline of liver（P 0.01）.The expression of TLR4 protein began to increase significantly from 1 week（P 0.01）,and to decline at 4 weekand 6 week（compared with 2 week,P 0.05）,but still higher than the normal control group（P 0.01）.The location of TLR4 protein was found in kupffer cells,activated hepatic stellate cells,a few hepatic cells and endothelium cells.Conclusion Endotoxin and its receptor TLR4 might plays an important role in the liver fibrosis induced by CCl4 induced.