Rosiglitazone prevents nutritional fibrosis and steatohepatitis in mice

Abstract

Objective. Currently, no agent has been confirmed as preventing the fibrosing progression of non-alcoholic steatohepatitis (NASH). In this study, rosiglitazone was used in the clinical treatment of insulin resistance in patients with type 2 diabetes mellitus. However, its protective effect on non-alchoholic fibrosing steatohepatitis is not clear. The study aimed to elucidate the effect and the mechanism of rosiglitazone in inhibiting nutrition-related fibrosis in mice. Methods. C57BL6/J mice were fed a high fat, methionine-choline deficient (MCD) diet for 8 weeks to induce hepatic fibrosis, and rosiglitazone was given in the treated group. The effect of rosiglitazone was assessed by comparing the severity of hepatic fibrosis in liver sections, the activation of hepatic stellate cells (HSCs) and the expression of TGF-β1 and connective tissue growth factor (CTGF). Results. At week 8, MCD-diet-induced fibrosing NASH models showed increased serum ALT and AST levels, severe hepatic steatosis, and infiltration of inflammation and fibrosis which, associated with down-regulated PPARγ mRNA and protein expression, up-regulated α-SMA protein expression and enhanced TGF-β1, CTGF mRNA and protein expression. Rosiglitazone significantly lowered serum ALT and AST and it reduced MCD-induced fibrosis by repressing levels of α-SMA protein expression and pro-fibrosis factors TGF-β1 and CTGF. It also restored expression of PPARγ. Conclusions. The present study provides clear morphological and molecular biological evidence of the protective role of rosiglitazone in ameliorating nutritional fibrosing steatohepatitis. Rosiglitazone may ameliorate hepatic fibrosis by activating PPARγ, which can inhibit HSC activation and suppress TGF-β1 and CTGF expression.