P17: Ethanol-induced ultrastructural changes in rat cerebellum after gene therapy

Abstract

Ethanol-induced oxidative impairment of tissues is in the focus of interest for gene therapy. The one of the most important antioxidant enzyme is superoxiddismutase (SOD), especially mitochondrial Mn-SOD. Previous experiments on rats have shown that tissues sensitive to ethanol-induced oxidative stress are cerebellar cortex and Purkinje cells (Celec et al., Life Sci, 2003). Male Wistar rats ( n =40) were randomly divided into four groups: control, alcohol, SOD, alcohol+SOD. Plasmid pcDNA3 containing the gene for mitochondrial Mn-SOD (300 μg in 100 μl TE buffer) or the same volume of saline was administered intramuscularly into the musculus biceps femoris of left hind limb once a week based information on the expression after non viral gene transfer from literature. Morphological analysis by TEM showed swollen mitochondria and impairment of myelin sheaths of nerve fibres in the brain in all groups except the control (water) group. Our antioxidative therapy has revealed no protective effect on ethanol-induced cerebellum impairment. In addition to SOD supplement in the form of plasmid, pcDNA3 caused pathological changes in mitochondria and myelin structure. This result indicates an elevated activity of SOD without appropriately elevated activity of catalase or glutathione peroxidase – enzymes that detoxify SOD product – hydrogen peroxide. It is possible, that hydrogen peroxide decomposes nonenzymatically into hydroxyl radical. It is more reactive than superoxide anion. The approach of using SOD gene therapy for antioxidant treatment of alcohol-induced tissue damage failed to show a clear positive effect. Further studies using a combination of antioxidant genes should follow. This work was supported by grant of Slovak Research and Development Agency No. APVT-20-003104.