The Effect of Ginkgo biloba Extract (EGb 761) on Hepatic Sinusoidal Endothelial Cells and Hepatic Microcirculation in CCl4 Rats

Abstract

It has been shown that Ginkgo biloba Extract (EGb 761) increases peripheral and cerebral blood flow and microcirculation and improves myocardial ischemia reperfusion injury. This study was designed to investigate the effect of EGb 761 on hepatic endothelial cells and hepatic microcirculation. Sixty male Wister rats were divided into normal, carbon tetrachloride ( CCl 4) and EGb groups, and were given normal saline, CCl 4 and CCl 4 plus EGb 761, respectively, for 10 weeks. Samples were taken from the medial lobe of the rat livers ten weeks later. Hepatic sinusoidal endothelial cells and other parameters of hepatic microcirculation were observed under transmission electron microscopy (TEM). The amount of malondialdehyde (MDA), endothelin (ET-1), platelet-activating factor (PAF) and nitric oxide (NO) in liver tissue was determined by spectrophotometry and radioimmunoassay, respectively. Compared with the CCl 4 group, aggregation of blood cell or micro thrombosis in hepatic sinusoids, deposition of collagen in hepatic sinusoids and space of Disse, injury of endothelial cells and capillization of hepatic sinusoid was significantly reduced in the EGb group. The amount of MDA, ET-1 and PAF was markedly reduced in the EGb group than in the CCl 4 group, while no significant difference in the amount of NO was observed between the two groups. The results demonstrate that EGb 761 has protective effect on hepatic endothelial cells and hepatic microcirculation in rats with chronic liver injury induced by CCl 4. The mechanisms may involve its inhibition on ET-1, PAF and lipid peroxidation.