Aim: To investigate the protective effect of ginkgo biloba extract (GBE) on livers of aged rats and the associated mechanisms.
Methods: Two-mo- and 20-mo-old rats were treated with GBE/saline for 3 mo. Liver tissue samples from 5-mo-old rats treated with saline (group Y) and 23-mo-old rats treated with GBE (group E) or saline (group N) were used for histopathological examinations (hematoxylin-eosin and Masson staining, Lipofuscin staining-Schmorl staining) and determination of expression of tissue inhibitor-1 of metalloproteinase (TIMP-1) and the level of malondialdehyde (MDA), glutathione peroxidase (GPx) and superoxide dismutase (SOD). Blood samples were collected for determination of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL) and albumin.
Results: Microscopic studies with Masson staining revealed mild liver fibrosis in aged rats (group N), while the livers of aged rats receiving GBE (group E) showed amelioration in fibrosis (2.2+/-0.1 vs 2.8+/-0.1, P<0.01) and deposition of lipofuscin (33.7+/-5.3 vs 62.8+/-5.7, P<0.01). The expression of TIMP-1 and the level of liver MDA (1.0+/-0.1 vs 1.2+/-0.2, P<0.05) also decreased but the activity of GPx (97.1+/-15.3 vs 61.8+/-14.5, P<0.01) increased in group E. Compared with group Y, the level of liver MDA (0.8+/-0.1 vs 1.2+/-0.2, P<0.01), lipofuscin (32.4+/-6.0 vs 62.8+/-5.7, P<0.01) and TIMP-1 expression were increased, while the activity of GPx (103.2+/-17.6 vs 61.8+/-14.5, P<0.01) and SOD (16.7+/-4.4 vs 11.8+/-3.9, P<0.05) was decreased in group N. There was no difference in liver function among these three groups.
Conclusion: GBE has protective effects on aging liver. The possible mechanisms might be its antioxidant activity and inhibition of TIMP-1 expression.