Protective effects of Ginkgo biloba extract EGb 761 on myocardium of experimentally diabetic rats - I: Ultrastructural and biochemical investigation on cardiomyocytes

Chronic diabetes in man and animal models develops cardiomyopathic alterati ons which cannot be absolutely avoided by insuline therapy. Since diabetic damage is part ly attributed to oxidative stress antioxidative treatment co uld be able to reduce the alterations. Aim of this study was to investigate the cardioprotective effects of EGb 761, Known as a radical scavenger, aga inst diabetic alterations in rats. The diabetes was induced by i.p. injection of 60 mg/kg body weight streptoz otocin. Duration of diabetes was 4 months, the protected group received 100 mg/kg body weight EGb 761 with the drinking water over 3 months. Electron and light microscopic morphometry of left-ventricular samples reve aled typical diabetic alterations consisting in decrease of volume fraction of myofibrils, SR and t-tubules and diminishing of cardiomyocyte diameter, increase of interstitial volume, mitochondrial size and volume fraction, a nd of vacuoles and of lipid drops. EGb treat ment could gradually prevent t he loss of myofibrils and reduction of myocyte diameter but has only little influence on interstitial and mitochondria volume. The diabetic-induced in crease of lipid and vacuoles and the decrease of SR and t-tubules were not influenced. Biochemical parameters of oxidative stress: malondialdehyde (MDA) was only insignificantly altered by diabetes and EGb. The superoxide dismutase (SOD) activity was in creased by diabetes and more increased by EGb treatment. C reatine kinase (CK) activity was diminished by diabetes but slightly increa sed by EGb. The polymerase chain reaction (PCR) of i-NOS was not different between the diabetic and protected diabetic groups.