Abstract
The change of endogenous superoxide dismutase (ESOD) during myocardial ischaemia and reperfusion and the efficacy of oxygen free radical scavengers in myocardial protection were investigated in an isolated heart model connected to a recirculating nonpulsatile perfusion circuit. Subjected to a two-hour period of global ischaemia at 27°C, the heart was reperfused at 37°C with oxygenated diluted autogenous blood for 60 minutes. Superoxide dismutase plus catalase were added to the cardioplegic solution and reperfusates. ESOD activity was measured by the pyrogallol method. Our experiment demonstrates that ESOD activity after ischaemia and reperfusion is decreased by the addition of free radical scavengers (SOD and CAT) to the cardioplegic solution and the reperfusates. In addition, SOD and CAT addition was also associated with reduced leakage of myocardial enzymes, reduced coronary vascular resistance and lessened ultrastructural damage to the myocardium. These results suggest that the use of SOD and CAT may inhibit myocardial reperfusion injury by scavenging oxygen-derived free radicals.
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