Oxygen free radical-induced damage during colonic ischemia/reperfusion in rats.

Reperfusion injury following ischemia is thought to be the consequence of reactive oxygen species. Role of these free radicals on the damaging effects of ischemia in colon has been investigated. A rat experimental model was used in which colon was subjected to ischemia and reperfusion and mucosal damage was assessed by biochemical and histological studies. Activity of myeloperoxidase, a neutrophil marker, was increased after ischemia (I) and ischemia/Reperfusion (I/R). Lipid peroxidation products such as malonaldehyde and conjugated diene did not show any change in the experimental colonic mucosa as compared to control. Mucosal level of low molecular weight thiols were found to be altered after I/R. A decrease in alpha-tocopherol level was noticed after ischemia and the decrease was prominent after reperfusion. Histology indicated morphological changes in colon due to ischemia and reperfusion and the damage was more severe after reperfusion. These results suggest that colonic mucosal damage occurs during I/R and free radicals generated by the infiltrated neutrophils may play a role in this damaging process.