Effect of intraarterial active oxygen species on the rat pancreas.

To explore the role of active oxygen species in the development and progression of acute pancreatitis, we studied the direct toxic effect on the rat pancreas of active oxygen species: superoxide anions generated by xanthine/xanthine oxidase (X/XO), and hydrogen peroxide (H2O2). After a continuous injection of X (10(-3)M, 0.9 ml/hour)/XO (1 U/ml, 0.3 ml/hour) into the celiac artery supplying the pancreas, hemorrhages and extensive edema developed in the pancreas. The amylase and lipase concentrations in the peritoneal fluid rose to 10.3 and 13.8 times the control values, respectively. The subsequent infusion of superoxide dismutase (SOD, 3600 U/hour) into the external jugular vein completely suppressed hemorrhages, and reduced edema and the amylase and lipase concentrations in the peritoneal fluid. After continuous injection of H2O2 (100 microM, 1.2 ml/hour), via the celiac artery, marked hemorrhages and edema appeared in the pancreas, and the amylase and lipase concentrations in the peritoneal fluid were 11.1 and 17.3 times higher than the control values, respectively. These abnormalities were significantly suppressed by the intravenous infusion of catalase (10 mg/kg/hour) or gabexate mesilate (10 mg/kg/hour). These results indicate that active oxygen species have a direct toxic effect on the pancreas and that free radicals may play an important role in the development of acute pancreatitis.