Measurement of oxygen-derived free radical generation in the regionally-ischemic rat heart by the chemiluminescence method.

Generation of oxygen-derived free radicals (oxy-radicals) in the stored rat heart was measured by chemiluminescence. Hearts subjected (ischemia) or not subjected (non-ischemia) to a 4-min regional ischemia were frozen in liquid nitrogen and stored until assayed. The frozen myocardium was ground and oxygenated by mixing it with phosphate-buffered saline (Po2: 194 mmHg) containing lucigenin. The chemiluminescence intensity of ischemic myocardium was larger than that of non-ischemic myocardium. Recombinant human superoxide dismutase significantly decreased these intensities. These results indicate that O2- is one of the major oxy-radical species in the rat heart and that the generation of oxyradicals is enhanced by regional ischemia for 4 min.