RADICAL TRAPPING BY PBN DURING REPERFUSION IN RABBIT GASTRIC-MUCOSA

Oxygen free radicals have been considered as a cause of ischemia-reper fusion injury in several organs, but this injury in a stomach, contain ing acid, may progress to severe damage. Thus, we examined the effect of ischemia-reperfusion and milk-intake on rabbit gastric mucosa. The gastric mucosal blood flow was increased after milk-intake, and gastri c rupture was detected. Superoxide dismutase activity measured by an i mproved nitroblue tetrazolium reduction method and thiobarbituric acid reactive substances in serum is increased during ischemia-reperfusion and milk-intake. By using alpha-phenyl N-tert-butyl nitrone (PBN) as a spin trap and electron paramagnetic resonance (EPR), we detected lip idic radicals from tissue samples in chloroform-methanol solvent only during reperfusion and milk-intake period; no signal was detected befo re. The EPR signal of spin adducts obtained in the sample after ischem ia-reperfusion and milk-intake would be a mixture of peroxyl and alkox yl radicals from the analysis of coupling constants.