Direct measurement of free radical generation following reperfusion of ischemic myocardium

摘要: Electron paramagnetic resonance spectroscopy was used to directly measure free radical generation in perfused rabbit hearts. Hearts were freeze-clamped at 77 degrees K during control perfusion, after 10 min of normothermic global ischemia (no coronary flow), or following post-ischemic reperfusion with oxygenated perfusate. The spectra these hearts exhibited three different signals power saturation and temperature stability: signal A isotropic g = 2.004; B anisotropic axial symmetry parallel 2.033 perpendicular 2.005; C an triplet 2.000 hyperfine splitting 24 G (1 0.1 mT). values, linewidth, saturation, stability are identical those a carbon-centered semiquinone, whereas similar alkyl peroxyl superoxide oxygen-centered radicals; is most likely nitrogen-centered radical. In the heart samples predominated, ischemic decreased intensity, became more intense; all markedly increased. Free concentrations derived from intensities peaked sec initiation reflow. At this time concentration intensity increased over six times measured two Hypoxic did not increase any levels observed ischemia. These experiments demonstrate that reactive radicals generated burst oxygen occurs within moments reperfusion.