| Backgroud and Objective: Liver fibrosis is a common sequel of varies liver injuries. The development of liver fibrosis is due to increased synthesis, deposition, and possibly reduced degradation of hepatic extracellular matrix(ECM) components. Fibronectin(FN) is one of the essential component of ECM. Research indicated that FN increased in the early stage of liver fibrosis. The activation of hepatic stellate cells is the key factor of liver fibrogenesis. The aims of this study are to investigate the variation of FN, integrinα5β1 and HSC activation during liver fibrogenesis, and to reveal the mechanisms of Salvianolic Acid B(SA-B) inhibiting liver fibrosis.Methods: 1.in vivo: Thirty male Wistar rats were randomly divided into 3 groups with 10 in each group: normal control, model control and SA-Btreated group. Model of liver fibrosis was induced in rats by intraperitoneal of dimethylnitrosamine(DMN) at a dose of 10μg·kg-1every other day for 4 weeks, a total of 14 times DMN injections. In the treated group, the rats were administered with SA-B at the beginning of model producing;rats in the normal group and model group were administered with with 0.9% NaCl at the same dose.Four weeks later, all the rats were sacrificed to detect levels of serum alanine aminotransferase(ALT), aspartate aminotransferase(AST), total bilirubin(TBil) and albumin(ALb). Liver inflammation and collagen deposition were evaluated with HE staining.The contents of hepatic hydroxyproline(Hyp) were measured by Jamall's method. The expression ofα-SMA, FN and integrinα5β1 protein in liver was determined by immunohistochemistry. The activities of MMP-2 and MMP-9 in liver tissue were assayed by gelatin zymography.2.in vitro: HSC-T6 cell line was cultured on uncoated and FN-coated plastic dishes for 4h,8h,12h,24h, 36h respectively. Passage 2 HSC-T6 were selected to divided into four groups: normal uncoated group, FN-coated group, 10-5 and 10-6M drug serum containing SA-B and FN-coated group. HSC proliferation was observed by MTT and alamarBlue .The expression ofα-SMA and integrinα5β1 protein in HSC was determined by immunofluorescence and Western Blot.Results: Compared with normal control, the mean body weight and liver/body weight index of model group were decreased significantly(p<0.05),compared with model group, the mean body weight and live/body weight index of SA-B group were increased. With the intoxication proceeded, there are many fibre hyperplasia and deposit inside portal area and hepatic lobule,excess collagen deposition, abnormal liver function, a high content of Hyp in liver (p<0.01), high protein expressions of FN andα-SMA(p<0.01), and increased activities of MMP-2 and MMP-9(p<0.01) were observed in model group. SA-B improved the rat liver function, decreased the content of Hyp in liver, and alleviated the FN deposition(p<0.01), inhibited the expression of integrinα5β1 andα-SMA of liver tissue, decreased the activities of MMP-2(p <0.01) and MMP-9(p<0.05).Serum significantly promoted HSC-T6 spreading, proliferation. FN increasedα-SMA andα5β1 expression of HSC-T6. As the culture duration prolonged, these effects disappeared. SA-B also inhibited the effect of FN on HSC-T6 proliferation andα-SMA expression, and decreased the expression of integrinα5β1.Conclusion: SA-B could alleviate inflammation and necrosis of hepatocytes obviously, inhibit the deposition of collagen in liver, had the role of delaying the development of live fibrosis. The effective characteristics of SA-B include the inhibition ofα5β1 expression, FN expression and deposition of ECM.
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