Expression Of Toll-like Receptor 4 In The Liver During Experimental Hepatic Fibrosis

【Objective】To investigate the dynamic expression patterns of TLR4 protein in rat liver tissues with chronic fibrogenesis and explore the relationship of TLR4 expression and the pathogenesis of hepatic fibrosis.【Methods】Forty-one female Wistar rats(230g±20g)were randomly divided into the normal control and model groups.The model group then was randomly allocated into 4 equal groups. The hepatic fibrosis was induced by subcutaneous injection of carbon tetrachloride(CCl₄)At the end of the experiment,rats were killed under pyrogen-free technics for collection of blood and liver tissue.Liver tissues were stained with hematoxylin-eosin to observe liver injury;The degree of liver fibrosis was observed by stained of sirius red of collagen and the content of hydroxyproline in liver tissues;Endotoxin was measured with a Limulus Amebocyte Lysate test kit;The ALT of plasma was mensurated with laishi method.The liver cellular localization of TLR4 protein was studied by immunohistochemistry.To observe the activation of hepatic stellate cells,a-smooth muscle actin(α-SMA)immunohistochemistry was adopted;In the course of hepatic fibrosis,the quantity of TLR4 protein in liver tissues was assessed by western-blot analysis.【Results】During the course of experimental hepatic fibrosis of rats:1.The leveles of plasma endotoxin ascended markedly.After four weeks carbon tetrachloride administration,contents of hydroxyproline and collagen in liver tissues began to increase obviously.2.The result of immunohistochemistry showed:in normal rats,had minim TLR4 protein expression in liver tissues.The expression of TLR4 in liver tissues began to increase significantly from the one week after carbon tetrachloride administration,and remained express highly after it,including kupffer cell,activated hepatic stellate cells,a few hepatic cells and endothelium cells,et.3.The result of Western-blot showed:the TLR4 expression in liver tissues began to increase from one week after carbon tetrachloride administration,and reached pinnacle at the 2nd week.It descended at the 4th week,but still higher than that in normal control group.【Conclusions】During hepatic fibrosis:1.With the forming of intestinal endotoxemia,The expression of endotoxin receptor TLR4 protein in liver tissues increased markedly also.2.High expression of TLR4 came from kupffer cells and activated hepatic cells.3.The leveles of plasma endotoxin ascended gradually,but intensity of TLR4 in liver tissues ascended firstly descended afterward,indicated TLR4 might play an important role during hepatic fibrosis induced by carbon tetrachloride. 【Objective】To observe the action of Astragalus on anti-hepatic fibrosis,in order to probe into the mechanism of Astragalus resisting hepatic fibrosis.【Methods】Seventy-two female Wistar rats(230g±20g)were randomly divided into the normal control,model groups and Astragalus Injection groups,the two groups then were randomly divided into one week group,two week group,four week group and six week group..Each group of Injection groups was administered to CCl₄,at the same time,Astragalus Injection (800mg/kg/d)was administered by subcutaneous injection.At the end of the experiment,rats were killed under pyrogen-free technics for collection of blood and liver tissue.Liver tissue was stained with hematoxylin-eosin to observe liver injury;The degree of liver fibrosis was observed by stained of sirius red of collagen and the content of hydroxyproline in liver tissue;Endotoxin was measured with a Limulus Amebocyte Lysate test kit;The ALT of plasma was mensurated with laishi method.The content of malondialdehyde(MDA)in liver tissue was determined with TBA method.The intensity of the expression of TLR4 protein in liver tissue were mensurated by western-blot immunohistochemistry,in order to observe the effect of Astragalus to it during the hepatic fibrosis【Results】Astragalus groups compared with the same time of model groups:1.The damnified changes of the liver ameliorated in different degree;2.Endotoxin content of plasma,ALT and MDA content in liver tissue all decreased in different degree;3.At the 4th and 6th week,HYP in the liver tissue began to reduce markedly,at the 6th week,FI of liver tissue reduced markedly also;4.The expression of TLR4 in liver tissue increased first decreased afterward(at 1st week it increased;at 2nd and 6th week,it decreased),and it did not have correlation with the change of endotoxin in plasma.【Conclusions】1.Astragalus can alleviate CCl₄ induced liver injury,stave happening and developing of hepatic fibrosis.2.Astragalus resisted hepatic fibrosis could correlate with:it staved intestinal endotoxin,alleviated lipid peroxide and affected the expression of TLR4 in liver tissue.