| Background/Objectives:Cholestasis is a disease of the hepatobiliary system that can be caused by a variety of factors,including impaired bile production,secretion and excretion.When cholestasis occurs,bile cannot be discharged through the biliary ducts into the intestinal cavity,accumulate in the liver and return to the blood,resulting in liver metabolic disorders,dysfunction,and then lead to organic liver damage.Primary sclerosing cholangitis(PSC)is a cholestasis syndrome of uncharted etiology,with clinical manifestations including fatigue,pruritus,and jaundice.Currently,few drugs have been proven to interfere with the progression of PSC,and liver transplantation is the only treatment option for patients with advanced disease.Hepatic fibrosis is a pathophysiological process of abnormal hyperplasia of hepatic connective tissue caused by various pathogenic factors.PSC is also one of the causes of hepatic fibrosis.The histopathological characteristics of PSC are annular fibrosis and inflammatory cell infiltration around the bile duct,and the typical cases are centripetal onion skin fibrosis changes.The excitation of hepatic stellate cell(HSC)has a crucial impact on the formation of fibrosis.The long-term existence of harmful factors leads to the excessive activation of HSC,which has adverse effects on the liver.It is of great clinical significance to elucidate the molecular mechanism and to explore drugs for the treatment of hepatic fibrosis associated with PSC.Artesunate(ART),which is a derivative of artemisinin.Artemisinin is a very low content terpenoid compound in the flowers and leaves of the Chinese herb Artemisia annua L..In addition to its anti-malarial activity,artesunate also has anti-cancer,anti-viral,antiinflammatory and ameliorative effects of fibrosis.On account of its low toxicity and high safety,artesunate’s anti-fibrosis effect has attracted wide attention in recent years.Although artesunate has been reported to be effective in the treatment of organ fibrosis caused by multiple reasons,the effect of artesunate on liver fibrosis in mice with PSC is still lacking.Abcb4-KO mice and 0.1% DDC-fed mice,the mouse models we used in this study,are common animal models of PSC.We first checked into the functions of artesunate on liver injury and liver fibrosis in mice with PSC in vivo.Then,the molecular mechanism of artesunate improving liver fibrosis was further investigated in HSC.Methods:1.We constructed animal models associated with PSC and treated them with artesunate(30 mg/kg).We detected bile acid content and the expression level of bile acid synthesis related genes in mouse liver.2.The expression levels of serum ALT,AST and ALP were determined.The content of hydroxyproline(HYP)in mouse liver and the mRNA changes of α-SMA,Col1a1 and Col1a2 genes,which are key indexes of fibrosis,were detected.H&E staining and Sirius red staining were used to further evaluate the degree of liver damage and liver fibrosis in mice.3.LX2 cells were activated with 10 ng/mL TGF-β1 and treated with artesunate and corresponding inhibitors.Immunofluorescence,Flow cytometry and Western blot were used to explore the molecular mechanism of the anti-fibrosis effect of artesunate in vitro.Results:1.Artesunate decreased bile acid content in the liver of Abcb4-KO mice and 0.1% DDCfed mice,and decreased the expression of bile acid synthesis-related indicators such as Cyp7a1.2.Artesunate administration significantly improved liver injury and fibrosis in mice with PSC.3.Artesunate repressed the activation and proliferation of HSC,and inhibited the excitation of TGF-β/SMAD pathway and PI3K/AKT/mTOR pathway,and the two pathways interacted to some extent.Conclusion:Artesunate reduces BA accumulation in the liver of Abcb4-KO mice and 0.1% DDC-fed mice,and significantly improves liver damage and fibrosis in mice with PSC.Artesunate inhibits the activation and proliferation of HSC by regulating TGF-β/SMAD pathway and PI3K/AKT/mTOR pathway,thus exerting its anti-fibrosis effect. |
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