The effects of gentamicin on the activities of glutathione peroxidase and 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 heart tissues from guinea pigs treated with gentamicin and gentamicin plus vitamin E combination. Mean values were compared with those of the controls treated with only physiological saline solution. The activities 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 the controls. In the gentamicin plus vitamin E group, however, tissue SOD activity was found to be increased and MDA level decreased significantly 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 of which is increased MDA level in the heart tissues from gentamicin-treated guinea pigs. This effect might be deleterious when gentamicin is used after cardiac surgery since a potential risk of free radical injury exists in the heart tissue during and/or after cardiac surgery owing to ischaemia and reperfusion processes, and, possibly, in the management of the patients with certain types of heart disease. Our results showed that vitamin E given concomitantly with gentamicin could protect the heart tissue against free radical injury.