ABSTRACT
Objective To study the effect of ursolic acid (UA) intervention on hepatocyte apoptosis induced by TGF-β1 and its potential mechanism.Methods Primary hepatocytes were extracted from healthy SD rats by in situ perfusion,cultured for 12-24h,then randomly divided into the following groups:blank control group,UA control group (UA 25μmol/L),TGF-β1 group (TGF-β1 2.5ng/ml),UA intervention group (UA 25μmol/L and TGF-β1 2.5ng/ml),DPI intervention group (DPI 0.5μmol/L and TGF-β1 2.5ng/ml).Each group was treated with drugs for corresponding time and their proliferation and apoptosis were detected by flow cytometry,the expression of CD95 (Fas) mRNA was analyzed by RT-qPCR,the expression of protein CD95 and membrane translocation of NADPH oxidase (NOX) subunit p47Phox were analyzed by Western blotting,and the reactive oxygen species (ROS) generation in primary hepatocytes was analyzed with reactive oxygen detection kit.Results UA intervention at 30min before TGF-β1 stimulating hepatocytes markedly reduced hepatocyte apoptosis (63.97 ± 3.19 vs 80.53 ± 1.56,P＜0.01) and promoted hepatocyte proliferation (18.67 ± 1.60 vs 10.83 ± 2.03,P＜0.01).UA intervention notably down-regulated the expressions of CD95 mRNA and protein (1.28 ± 0.15 vs 2.40 ± 0.25,P＜0.01;1.05 ± 0.15 vs 1.37 ± 0.18,P＜0.05),restrained membrane translocation of p47phox (1.13 ± 0.12 vs 1.76 ± 0.22,P＜0.01),and decreased ROS level in primary hepatocytes induced by TGF-β1 (2.12 ± 0.45 vs 3.23 ± 0.53,P＜0.01).Conclusion The mechanism of UA inhibiting hepatocyte apoptosis induced by TGF-β1 is likely to be that UA intervention reduced hepatocyte apoptosis by inhibiting NOX activation and decrease generation of ROS so as to down-regulate expression of CD95 in hepatocytes.