Primary Biliary Cirrhosis Pathogenesis And Drug Treatment To Explore

Section one Establish and identify the animal model of primary biliary cirrhosisBackground:Primary biliary cirrhosis(PBC) is one of the organ specific autoimmune diseases characterized by destruction of the biliary epithelial cells, cholestasis,liver cirrhosis,and liver failure.With the postulation that induction of the autoimmune process might induce PBC-like cholangitis,here we used polyinosinic polycytidylic acid(poly I:C),an inducer of type-1 interferon(IFN),to generate an autoimmune cholangitis animal model.Methods:Female C57BL/6 mice were injected with 5 mg/kg of poly I:C twice a week for 24 consecutive weeks.Liver specimens were collected to evaluate the degree of cell infiltration.Autoantibodies, including antimitochondrial antibodies(AMAs),were assayed by immunofluorescence (IIF) and enzyme-linked immunosorbent assay(ELISA).Results:Mononuclear cells were detected at the portal areas 8 weeks after the start of poly I:C injection,which progressed up to 24 weeks.Autoantibodies,including AMAs,were detected in the sera from all poly I:C injected mice.Conclusions:A PBC-like cholangitis in a genetically susceptible mouse strain because of poly I:C administration.This model would be helpful to study PBC immunopathogenesis and to evaluate the effectiveness of newly developed therapeutic regimens for PBC. Section two Aberrant TGF-β1 signaling contributes to the development of primary biliary cirrhosis in murine modelBackground:Primary biliary cirrhosis(PBC) is an autoimmune liver disease, characterized by lymphocytic infiltration in portal tracts,selective destruction of biliary epithelial cells,and anti-mitochondrial antibodies(AMAs).Recent studies suggest that TGF-β1 signaling pathway might play an important role in the pathogenesis of PBC.Aims:To investigate whether TGF-β1 signaling pathway is involved in the pathogenesis of PBC.Methods:A murine model of PBC was developed by injection of polyinosinic polycytidylic acids(poly I:C) in C57BL/6 mice,and the liver expressions of TGF-β1,TGF-βreceptorⅠ(TβRⅠ),TGF-βreceptorⅡ(TβRⅡ),p-Smad2/3,α-smooth muscle actin(α-SMA) andα1(Ⅰ) collagen in mice model and control mice were evaluated by immunohistochemistry,immunoblotting and semi-quantitative real-time PCR.Lymphocyte subsets in liver and spleen were analyzed using flow cytometry.Results:The mice model had several key phenotypic features of human PBC,including elevated levels of alkaline phosphatase(ALP), AMAs,portal bile ducts inflammation,and progressive collagen deposition.Protein and mRNA levels of TGF-β1,TβRI,TβRⅡ,p-Smad2/3,α-SMA andα1(Ⅰ) collagen were higher in liver from mice model compared with that in control mice(P＜0.05),as well as the total number and percentage of CD4~+CD25~+FOXP3~+ and CD8~+ lymphocytes(P＜0.01).Conclusion:TGF-β1 might play a dual role in the development of PBC:it suppresses inflammatory response but operates to enhance fibrogenesis on the other hand.The aberrant activity of TGF-β1 signaling contributes to the development of PBC. Section three Curcumin Prevents and Ameliorates the development of primary biliary cirrhosis in murine modelBackground & Aims:Curcumin is well documented to have a variety of beneficial effects,including antioxidative,anti-inflammatory and anti-fibrosis activities.Recent evidence suggests that it may be of therapeutic interest in chronic liver disease.The aim of this study was to determine whether treatment with curcumin prevented and ameliorated portal inflammation in a murine model of primary biliary cirrhosis(PBC). We also tested whether inhibition of transforming growth factor-β1(TGF-β1) via peroxisome proliferator-activated receptorγ(PPARγ) by curcumin was involved in these mechanisms.Methods:A murine model of PBC developed by injection of polyinosinic polycytidylic acids(poly I:C) in C57BL/6 mice were treated with curcumin(200,400 or 800 mg/kg/day),or vehicle by gavage.Anti-mitochondrial antibodies(AMAs),biochemical variables together with liver histology were evaluated.TGF-β1,TβRⅠ,TβRⅡ,p-Smad2/3,PPARγ,α-SMA andα1(Ⅰ) collagen were evaluated using immunohistochemistry,immunoblotting and semi-quantitative real-time PCR in liver.Results:Treatment of mice with curcumin prevented and improved both biochemical variables and histopathologic signs of murine model of PBC.Consistent with these findings,T-cell infiltration and TGF-β1 signaling pathway activity in liver were suppressed in the curcumin-treated group.Activation of PPARγin liver was also observed.Conclusions:This study has shown for the first time that treatment with curcumin can prevent and improve murine experimental PBC.This finding suggests that curcumin could be a potential therapeutic agent for the treatment of patients with primary biliary cirrhosis.