桦褐孔菌提取物介导LXRs信号通路调控肝纤维化

Study of Inonotus obliquus extract regulates liver fibrosis via mediating LXRs signaling pathway

目的探究桦褐孔菌提取物(Inonotus obliquus extract,IOE)介导肝X受体(liver X receptors,LXRs)信号通路调控肝纤维化。方法采用腹腔注射硫代乙酰胺(thioacetamide,TAA)建立小鼠肝纤维化模型。同时,通过口服灌胃给予不同浓度IOE及水飞蓟素连续干预4周。末次给药后,小鼠安乐死收集肝脏和血清。检测不同浓度IOE对大鼠肝星状细胞(hepatic stellate cells,HSCs)存活率的影响。转化生长因子-β(transforming growth factor-β,TGF-β)10μg·L^(-1)刺激HSCs 2 h,给予IOE(0、5、10、25μmol·L^(-1))处理6 h。测定小鼠血清谷氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)水平,观察肝脏组织病理学改变,并通过Western blot和RT-PCR法检测小鼠肝脏和活化HSCs中α-SMA、collagenⅠ、炎症因子以及LXRα/β的蛋白和mRNA表达。结果IOE可以明显降低TAA诱导的肝纤维化小鼠血清转氨酶水平,改善肝脏组织病理学变化。IOE能够减少小鼠肝组织和活化HSCs中ECM和胶原沉积,抑制IL-6、Caspase-1的表达,并明显上调LXRα/β的蛋白表达。结论IOE能够介导激活LXRs信号通路,调控细胞外基质和炎症因子的产生,有效逆转肝纤维化的发生和发展。

Aim To explore the regulation of Inonotus obliquus extract(IOE)in liver fibrosis via mediating LXRs signaling pathway.Methods The hepatic fibrosis model of mice was established by intraperitoneal injection of thioacetamide(TAA).Meanwhile,different concentrations of IOE and silymarin were given by gavage for four weeks.After the last administration,all mice were euthanized and liver tissue and serum collected.The effect of IOE on the survival rate of hepatic stellate cells(HSCs)was detected by MTT assay.HSCs stimulated with TGF-βat 10μg·L^(-1) for 2 h,followed by different concentrations of IOE treatment for 6 h.Serum biochemical indicators were measured and liver histopathological changes were observed,and the expressions ofα-SMA,collagen I,inflammatory factors and LXRα/βin liver tissue or activated HSCs were detected by Western blot and RT-PCR.Results IOE could significantly decrease the serum ALT and AST levels and ameliorate liver histopathological changes.IOE could reduce ECM and collagen deposition,inhibit the expressions of inflammatory factors,such as IL-6 and Caspase-1,and significantly up-regulated LXRα/βexpression in liver tissues and activated-HSCs.Conclusions IOE could mediate the activation of LXRs signaling pathway,regulate the production of extracellular matrix and inflammatory factors,and effectively reverse the occurrence and development of liver fibrosis.