Inhibition of lipid peroxidation by superoxide dismutase following regional intestinal ischemia and reperfusion.

In a feline model of regional intestinal ischemia, reoxygenation resulted in a rise in the concentration of oxidized glutathione, from 2.3 +/- 0.7 to 4.1 +/- 0.5% of the total glutathione. Also conjugated diene as an indirect measurement for lipid peroxidation increased after reperfusion from 2.5 +/- 0.5 mumol/g to 5.5 +/- 1.2 micrograms mol/g tissue. These results are in line with the hypothesis that ischemia results in an accumulation of hypoxanthine and a conversion of xanthine dehydrogenase into its O2-dependent form. Upon reoxygenation, hypoxanthine can be oxidized giving yield to a burst of O2-. and its interconversion products. These may initiate peroxidative tissue damage. Pretreatment of the cats with superoxide dismutase inhibited the biochemical alterations and protected the tissue from peroxidation damage.