Exogenous superoxide dismutase and catalase promote recovery of function in isolated rat heart after regional ischemia and may be transported from capillaries into myocytes

The effects of infusing superoxide dismutase (SOD) and catalase (CAT) into the coronary circulation were investigated in isolated, working rat hearts prior to and during a 15 minute episode of regional ischemia followed by 30 minutes reperfusion. Aortic output, left ventricular pressure and dP/dT were recorded. Compared to untreated hearts, SOD and CAT significantly improved function during reperfusion, but had no effect during the pre-ischemic or the ischemic period. To investigate possible transport of SOD and CAT into rat myocytes, cryotome sections of isolated, Langendorff perfused rat hearts were exposed to rabbit antibody prepared against the exogenous SOD and CAT. Bound antibody was detected by the indirect-fluorescent antibody test. The interior of myocytes from rat hearts exposed to SOD and CAT bound antibodies prepared against these enzymes, whereas myocytes from rat hearts not exposed to exogenous SOD and CAT only bound the CAT antibodies. This indicates the anti-SOD we prepared is specific for exogenous SOD, and also suggests exogenous SOD can gain access to the cytoplasm of myocytes from the coronary circulation.