THE EFFECTS OF GENTAMICIN ON THE ACTIVITIES OF GLUTATHIONE-PEROXIDASEAND SUPEROXIDE-DISMUTASE ENZYMES AND MALONDIALDEHYDE LEVELS IN HEART TISSUES OF GUINEA-PIGS

In this study, superoxide dismutase (SOD) and glutathione peroxidase ( GSH-Px) activities and malondialdehyde (MDA) levels were measured in h eart tissues from guinea pigs treated with gentamicin and gentamicin p lus vitamin E combination. Mean values were compared with those of the controls treated with only physiological saline solution. The activit ies of SOD and GSH-Px were found to be lower and the MDA level higher in the hearts from gentamicin-treated animals compared with those of t he controls. In the gentamicin plus vitamin E group, however, tissue S OD activity was found to be increased and MDA level decreased signific antly relative to the gentamicin group. GSH-Px activity was lowest in this group. Results suggest that gentamicin suppresses SOD and GSH-Px activities in heart tissue, thereby making the tissue more vulnerable to oxidative stress and peroxidative attacks, an important indicator o f which is increased MDA level in the heart tissues from gentamicin-tr eated guinea pigs. This effect might be deleterious when gentamicin is used after cardiac surgery since a potential risk of free radical inj ury exists in the heart tissue during and/or after cardiac surgery owi ng to ischaemia and reperfusion processes, and possibly in the managem ent of the patients with certain types of heart disease. Our results s howed that vitamin E given concomitantly with gentamicin could protect the heart tissue against free-radical injury.