Overexpression of thioredoxin prevents thioacetamide-induced hepatic fibrosis in mice.

ABSTRACT

BACKGROUND/AIMS: Thioredoxin is a small redox-active protein with anti-oxidant and anti-apoptotic effects. We have previously reported that thioacetamide-induced acute hepatitis was attenuated in thioredoxin transgenic mice. The aim of the present study was to investigate the protective effect of thioredoxin for hepatic fibrosis. METHODS: We subjected thioredoxin transgenic mice to thioacetamide-induced hepatic fibrosis. We also studied the effect of thioredoxin on the activation process of primary-cultured hepatic stellate cell. RESULTS: The expression of endogenous thioredoxin was induced in hepatocytes of thioacetamide-induced murine and rat fibrotic livers. Overexpression of thioredoxin inhibited tumor necrosis factor-alpha-induced apoptosis of HepG2 cells. Thioacetamide-induced fibrosis and accumulation of malondialdehyde were suppressed in transgenic mice as compared with wild type mice. Hepatic stellate cells isolated from transgenic mice were less proliferative than those isolated from wild type mice. Recombinant thioredoxin significantly inhibited DNA synthesis of primary-cultured stellate cells under serum or platelet-derived growth factor stimulation. CONCLUSIONS: Thioredoxin has a potential to attenuate hepatic fibrosis via suppressing oxidative stress and inhibiting proliferation of stellate cells.