THE SUPEROXIDE-DISMUTASE ACTIVITIES OF CEREBRAL TISSUES, ASSAYED BY THE CHEMILUMINESCENCE METHOD, IN THE GERBIL FOCAL ISCHEMIA-REPERFUSION AND GLOBAL-ISCHEMIA MODELS

Superoxide dismutase is well known to act as an effective antioxidant enzyme against cellular damage caused by oxidative stresses including ischemia/reperfusion-induced cerebral injury. However, it is still controversial whether or not the activity of endogenous superoxide dismutase changes during cerebral ischemia and reperfusion. In order to elucidate this phenomenon, we assayed the superoxide dismutase activity in the cerebral tissues of gerbils using the chemiluminescence method with a Cypridina luciferin analog. This method was demonstrated to be a sensitive and specific assay for the enzymatic activity of superoxide dismutase in cerebral tissues, which was not subject to interference from proteins or ascorbate. After 3 h of focal and global ischemia, there were no changes in the cerebral tissue superoxide dismutase activities. After 24 h of reperfusion following 1 h of ischemia, the superoxide dismutase activity decreased only approx 20%, whereas the adenylate kinase activities, measured in the same cerebral tissues. as those used for superoxide dismutase assay, started to decline 1 h after reperfusion commenced and were approx 50% of the control levels after 24 h. These results show that almost all the activity of endogenous superoxide dismutase is maintained and does not decrease significantly as a result of ischemia/reperfusion-induced cerebral injury.