Effects of extract from Ginkgo biloba on carbon tetrachloride-induced liver injury in rats

Aim: To study the effects of extract from Ginkgo biloba (EGb) containing 22% flavonoid and 5% terpenoid on chronic liver injury and liver fibrosis of rats induced by carbon tetrachloride (CCl4). Methods: All rats were randomly divided into control group, CCl4-treated group, colchicine-treated group and EGb-protected group. Chronic liver injury was induced in experimental groups by subcutaneous injection of CCl4 and fed with chows premixed with 79.5% corn powder, 20% lard and 0.5% cholesterol (v/v). EGb-protected group was treated with EGb (0.5 g/kg body weight per day) for 7 wk. At the end of wk 8, all the rats were killed. Liver function, liver fibrosis, oxidative stress and expression of transforming growth factor beta(1) (TGF-beta(1)), a-smooth muscle actin (alpha-SMA) and type I collagens in liver were determined. In addition, pathology changes of liver tissue were observed under light microscope. Results: The levels of alanine aminotransferase (ALT), aspartate aminotransferase. (AST) and albumin (Alb) in EGb-protected group were notably improved as compared with the CCL4-treated group (P<0.01). The contents of serum hyaluronic acid (HA), type III procollagen (PCIII), type IV collagen (CIV) and the expression of hepatic tissue TGF-beta(1), alpha-SMA and type I collagen in EGb-protected group were significantly lower than those in CCL4-treated groups (P<0.05, P<0.01). The degrees of liver fibrosis in EGb-protected groups were lower than those in CCL4-treated groups (6.58 +/- 1.25 vs 9.52 +/- 2.06, P<0.05). Compared to the CCL4-treated group, the levels of plasma glutathoine peroxidase (Se-GSH-Px), superoxide dismutase (SOD) and malondialdehyde (MDA) were strikingly improved also in EGb-protected group (P<0.05, P<0.01). Conclusion: EGb resists oxidative stress and thereby reduces chronic liver injury and liver fibrosis in rats with liver injury induced by CCl4. (C) 2006 The WJG Press. All rights reserved.