Recombinant human extracellular superoxide dismutase reduces concentration of oxygen free radicals in the reperfused rat heart

Study objective The aim of the study was to determine whether recombinant human extracellular superoxide dismutase type C (rh-EC-SOD C) has antioxidant effects similar to those of the previously studied Cu-Zn superoxide dismutase. Design Electron paramagnetic resonance spectroscopy was used for quantification of free radical generation during reperfusion of postischaemic isolated rat hearts. The hearts were perfused with Krebs-Henseleit buffer and then subjected to 15 min global ischaemia. N-tert-butyl-alpha-phenylnitrone (PBN) was added as a spin trapping agent to the perfusate. Experimental material 18 hearts from Sprague-Dawley rats (280-400 g) were used. Measurements and main results Reperfusion resulted in a burst of radical formation. In presence of rh-EC-SOD C plus catalase, the PBN spin adduct concentration was only 18% (p less than 0.05) of the value in the control group. With bovine Cu-Zn superoxide dismutase plus catalase added to the buffer the corresponding spin adduct formation was 44% of control (NS = v rh-EC-SOD C). Conclusions In isolated rat heart, rh-EC-SOD C reduces free radical concentrations at least to the same extent as Cu-Zn superoxide dismutase.