Identification of free radicals in myocardial ischemia/reperfusion by spin trapping with nitrone DMPO

Abstract

The spin trapping ESR technique was applied to investigate oxygen-derived radicals in ischemic and postischemic rat hearts. Using 5,5′-dimethyl-1-pyrroline-N-oxide, carbon-centered radicals were identified during ischemia and oxy-radical adducts (superoxide anion radical, O^.− ₂ and hydroxyl radicals, ^.OH) in postischemic rat heart. The formation of these spin adducts was inhibited by superoxide dismutase, suggesting that superoxide plays a role in the adducts' formation. The results demonstrate that oxygen derived free radicals are important byproducts of abnormal oxidative metabolism during myocardial ischemic and reperfusion injuries.