Protection by and anti-oxidant mechanism of berberine against rat liver fibrosis induced by multiple hepatotoxic factors.

1. The aim of the present study was to investigate the effect and mechanism of berberine, an alkaloid extracted from the traditional Chinese medicine coptis, on rat liver fibrosis induced by multiple hepatotoxic factors. 2. Male Wistar rats were separated into five groups, a normal control group, a fibrotic control group and fibrotic groups treated with three different doses of berberine. The fibrotic models were established by introduction of multiple hepatotoxic factors, including CCl(4), ethanol and high cholesterol. Rats in the treatment groups were administered 50, 100 or 200 mg/kg berberine, intragastrically, daily for 4 weeks. Serum levels of alanine aminotransferase (ALT) and serum aspartate aminotransferase (AST), hepatic activity of superoxide dismutase (SOD) and hepatic malondialdehyde (MDA) and hepatic hydroxyproline (Hyp) content were determined. Liver biopsies were obtained for histological and immunohistochemical studies to detect the expressions of alpha-smooth muscle actin (SMA) and transforming growth factor (TGF)-beta1. 3. The results showed that, compared with the fibrotic control group, serum levels of ALT and AST and hepatic content of MDA and Hyp were markedly decreased, but the activity of hepatic SOD was significantly increased in berberine-treated groups in a dose-dependent manner. In addition, histopathological changes, such as steatosis, necrosis and myofibroblast proliferation, were reduced and the expression of a-SMA and TGF-b1 was significantly downregulated in the berberine-treated groups (P < 0.01). 4. These results suggest that berberine could be used to prevent experimental liver fibrosis through regulation of the anti-oxidant system and lipid peroxidation.