Expression And Significance Of NF-κB In Experimental Hepatic Fibrosis

【Objective】To investigate the expression and distribution and significance of NF-κB in experimental hepatic fibrosis,in order to probe into the mechanism of hepatic fibrosis.【Methods】Seventy female Wistar rats(220g±20g) were randomly divided into the normal control group(n=6),hepatic fibrisis model group(n=32) and PDTC group(n=32),the latter two groups were then randomly divided into one-week group,two-week group,four-week group and six-week group(n=8per group).The hepatic fibrosis model groups and the PDTC groups were treated with subcutaneous injection of carboan tetrachloride twice a week,meanwhile,the PDTC groups with oral administration of PDTC 150 mg/kg/d.At the end of the first week,the second week,the fourth week,and the sixth week,rats including normal control group were killed as planned under pyrogen-free technic to collect blood and liver tissues.Paraffin embedded liver sections were stained with hematoxylin and eosin for routine histological analysis.The degree of liver fibrosis was assessed by morphometric measurement of collagen stained with sirius red, and measurement the content of hydroxyproline in liver tissue.Endotoxin was measured with a Limulus Amebocyte Lysate test kit.The ALT of plasma was measured with laishi method.The content of malondialdehyde(MDA) in liver tissue was determined by means of TBA method. The expression of NF-κB and ED2 in liver tissues determined by immunohistochemistry.The intensity of the expression of CTGF protein in liver tissues was measured by western-blot and in situ hybridization.【Results】The comparison between the hepatic fibrosis model group and the normal control group:1.The plasma ET levels began to increase significantly from the second week after carbon tetrachloride administration,and reached pinnacle at the 6th week.Enhanced expression of NF-κB was shown in liver fibrosis group compared with normal control group from the second week,and reached pinnacle at the 6th week.The CTGF expression in liver tissues began to increase from the fourth week,and reached pinnace at the 6th week.Furthermore,The levels of plasma ET and expression of NF-κB and CTGF correlated positively with each other,and the visible increase of plasma ET preceded that of CTGF in liver tissues.2.In control goup,Just a small amount of NF-κBp65 was expressed in a few hepatocytes cytoplasm around central veins. The positive staining of NF-κBp65 was detected mainly in fibrous stepta and hepatic sinusoid and partial vascular endothelial cells and part of proliferating ductular epithelial cells and impaired hepatocytes.A small amount of positive staining of ED2 was visible around fibrous septa. However compared with control group,the expression of ED2 signifcantly up-regulated mainly in fibrous septa.It was also detected in a few heptic cells.Futhermore the positive staining cells cytoplasm is affluent and the volume becomes larger.They take the shape of star or polygon,and some are irregular-shaped.PDTC groups compared with the same time model control groups: ET content of plasma increased significantly from the 2nd week,remarkably higher than that in the model group,and reached pinnacle at the 4th week,but began to decline at the end of the 6^th week,no significant difference from the normal control group.2.The expression of NF-κB and CTGF in liver tissues in PDTC groups was lower than that of model control groups(p＜0.05). Furthermore,the expression of NF-κB in liver tissues in PDTC groups correlated positively with CTGE 3.The levels of plasm ET was not correlated with the expression of NF-κB and CTGF.4. The expression of ED2 in liver tissues is lower than that in model control groups at the corresponding time period.【Conclusions】1.ET may up-regulate the expression of CTGF by activating NF-κB,thus speeding the occurrence and developing of hepatic fibrosis.2.ET may promote liver injury by means of NF-κB activated kupffer cell,by which takes part in the occurrence and developing of hepatic fibrosis.3.PDTC can alleviate CCL_4^- induced liver injury,occurrence and developing of hepatic fibrosis. 【Objective】To explore the effects of silybinin on hepatic fibrosis in rats.【Methods】Seventy female Wistar rats were randomly divided into normal control group(n=5), hepatic fibrosis model group(n=33) and silybinin treatment group(n=32).The hepatic fibrosis model group and silybinin treatment group were randomly divided into 4 subgroups respectively(n=6～11).The hepatic fibrosis model groups and the silybinin treatment group were treated with subcutaneous injection of carboan tetrachloride twice a week,while the silybinin 50 mg /(kg.d) was orally administrated simultaneously based on the injection of carboan tetrachloride in silybinin group.At the end of the first,2nd,4th,and 6th week after being given drugs and forming models,rats including normal control group were killed under pyrogen-free technics for collecting blood and liver tissues respectively.The pathology and histology changes were observed.The intensity of the expression of CTGF protein in liver tissures was assessed.The blood endotoxine(ET),hydroxyproline(Hyp),maleic dialdehyde(MDA) and alanine aminotransferase(ALT) were measured.【Results】Compared the hepatic fibrosis model groups with silybinin treatment groups and normal control group,all parameters were significantly increased,and ET is ahead of CTGF; Compared with the hepatic fibrosis model groups pathological injury of liver ameliorated in silybinin treatment groups,Endotoxin and ALT levels of plasma,MDA and Hyp in liver tissues decreased in different degree,the expression of CTGF in liver tissue dcreased significantly.【Conclusions】Silybinin can attenuate liver fibrosis by decreasing the content of endotoxin of plasma and the expression of CTGF in liver tissues.