Ultrastructural, immunohistochemical and biochemical investigations of the rat liver exposed to experimental diabetes und acute hypoxia with and without application of Ginkgo extract

Abstract

The aim of this paper was to investigate the effect of streptozotocin-induced diabetes by i.p. bolus injection of streptozotocin at 60 mg per kg bodyweight over four months and additional acute respiratory hypoxia (20 min. duration, 5% oxygen v/v), and also the protective effect of Ginkgo biloba extract (EGb 761) on Wistar rat liver under these experimental conditions. Diabetic and additional hypoxic alterations in histology and ultrastructure were subjected to qualitative and quantitative analysis, collagen was investigated by immunohistochemistry, and some biochemical parameters of oxidative stress were determined. Diabetes caused an increase in the size of the hepatocytes and their nuclei with a decrease in nucleus-to-plasma ratio and glycogen content. Connective tissue was variably increased in individual cases as shown by routine histological staining. EGb did not influence these data. Ultrastructural morphometry revealed a significant reduction in rough endoplasmic reticulum (rER) and a significant increase in smooth endoplasmic reticulum (sER) through diabetes, an increase under EGb protection, with no significant alteration under hypoxia. The volume fraction of mitochondria was significantly increased after induction of diabetes but less increased in the protected group. Additional hypoxia reduced this parameter. The mean cross-section area of mitochondria was significantly elevated in all diabetic groups compared to controls. Volume density of mitochondrial cristae was significantly diminished in all diabetic groups; EGb could only improve this parameter in the diabetic-hypoxic group.