Administration of Ginkgo biloba extract (EGb761) alone and in combination with FK506 promotes liver regeneration in a rat model of partial hepatectomy

Abstract

Background: Free radical damage is known to occur during liver regeneration. The Ginkgo biloba extract EGb761 has antioxidant properties due to its ability to scavenge free radicals. FK506 has been widely used as an immunosuppressant that stimulates hepatocyte proliferation following partial hepatectomy. Aims: To explore whether EGb761 enhances liver regeneration after hepatectomy in rats, we investigated the effects of EGb761 alone and in combination with FK506 on the liver regenerative process. Study Design: Animal experimentation. Methods: A total of 75 Wistar albino rats weighing 340.08±11.66 g were randomly divided into five experimental groups: sham, control, FK506, EGb761, and FK506 + EGb761. According to the study groups, rats were administered FK506 at a dose of 0.1 mg/kg/ day and EGb761 at 25 mg/kg/day three times via the intraperitoneal route. Then, two-thirds hepatectomy was performed according to the Higgins and Anderson technique in all the rats. At postoperative 48 h, 53 surviving rats were sacrificed. Serum and plasma samples were collected for analyzing thymidine kinase and oxidative stress marker levels. The regenerated liver was entirely resected, weighed, and sectioned. The mitotic index was assessed using hematoxylin-eosin staining. The extent of liver regeneration was calculated using the Child’s formula. The data were statistically analyzed using ANOVA, with a significance level of 5% (p<0.05). Results: Rats who received EGb761 showed significantly higher levels of liver regeneration than those who received FK506 or FK506 + EGb761 (p<0.01). Thymidine kinase level and mitotic index were significantly higher in the EGb761 (p<0.005) and FK506 (p<0.05) groups than in the control and sham groups. In addition, the liver regeneration percentage was significantly higher in the EGb761 group than in the FK506 group (p<0.01). Myeloperoxidase and malondialdehyde levels were significantly correlated between the EGb761 and FK506 groups, even at lower levels in the EGb761 group (p<0.001). Conclusion: EGb761, which is an antioxidant, reduces liver damage and stimulates liver regeneration following partial hepatectomy in rats through its anti-inflammatory and antioxidative effects.