Biodistribution of a polyethylene glycol-modified superoxide dismutase in mice and its effect on myocardial ischemia treatment in rats

We have performed a comparative study of the biodistribution in mice of native and monomethoxypolyethylene glycol-modified superoxide dismutase isolated from bovine liver after intravenous injection. Polymer modification greatly influenced the biodistribution of enzyme preparation. Monomethoxypolyethylene glycol-modified SOD (mPEG-SOD) exhibited a longer residence time and a considerably longer half-time in the blood, lungs, and heart than the native enzyme. Using a rat model of ischemia, we demonstrated that an intravenous bolus administration of mPEG-SOD reduced the size of the myocardium necrosis zone by 40% compared with a 13% reduction by native enzyme. These results suggest that mPEG-SOD is a promising agent for decreasing reperfusion injury to the cardiovascular system.