Enzymatic antioxidant defence mechanism in rat intestinal tissue is changed after ischemia-reperfusion. Effects of an allopurinol plus antioxidant combination

OBJECTIVES: TO establish the antioxidant status of rat intestinal tissues a fter ischemia-reperfusion and to determine if pretreatment with an allopuri nol and antioxidant vitamin combination gives any protection against mucosa l injury. EXPERIMENTAL ANIMALS: Twenty rats were divided into 4 groups of 5 animals e ach, METHODS: Group 1 (control) rats were not subjected to ischemia-reperfusion and received no allopurinol plus vitamin combination; group 2 rats received vitamins C (200 mg/kg) and E (100 mg/kg) and allopurinol (50 mg/kg) combin ation daily for 3 days prcoperatively; group 3 rats were subjected to ische mia-reperfusion only; and group 4 rats were subjected to ischemia-reperfusi on and received the vitamin and allopurinol combination. MAIN OUTCOME MEASURES: Activities of superoxide dismutase (SOD), glutathion e peroxidase (GSH-Px) and catalase (CAT) enzymes, the level of thiobarbitur ic acid-reagent substances (TBARS) and histologic grading of tissue samples , RESULTS: SOD and GSH-Px activities were decreased, but-the CAT activity and TBARS level increased. Pretreatment of the rats with the allopurinol-vitam in C -vitamin E combination did not have any significant effect on the enzy me activities. However, it resulted in important reductions in the TBARS ti ssue levels. Histologic investigation revealed significant mucosal injury i n group 3 rats compared with group 4 rats (mean [and standard deviation] fo r grading, 4.6 [0.5] versus 1.8 [0.4]). CONCLUSIONS: The enzymatic antioxidant defence system was significantly cha nged after ischemia-reperfusion and intestinal tissue was exposed to increa sed oxidant stress, the results of which were peroxidation of some cellular structures and increased concentrations of oxidative: products, Although a ntioxidant treatment did not drastically affect the enzyme activities or af ford complete protection of cellular structures against deformation, it app arently could eliminate oxygen radicals and prevent peroxidative reactions.