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 after ischemia-reperfusion and to determine if pretreatment with an allopurinol and antioxidant vitamin combination gives any protection against mucosal injury.

EXPERIMENTAL ANIMALS

Twenty rats were divided into 4 groups of 5 animals each.

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) combination daily for 3 days preoperatively; group 3 rats were subjected to ischemia-reperfusion only; and group 4 rats were subjected to ischemia-reperfusion and received the vitamin and allopurinol combination.

MAIN OUTCOME MEASURES

Activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) enzymes, the level of thiobarbituric 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-vitamin C-vitamin E combination did not have any significant effect on the enzyme activities. However, it resulted in important reductions in the TBARS tissue levels. Histologic investigation revealed significant mucosal injury in group 3 rats compared with group 4 rats (mean [and standard deviation] for grading, 4.6 [0.5] versus 1.8 [0.4]).

CONCLUSIONS

The enzymatic antioxidant defence system was significantly changed after ischemia-reperfusion and intestinal tissue was exposed to increased oxidant stress, the results of which were peroxidation of some cellular structures and increased concentrations of oxidative products. Although antioxidant treatment did not drastically affect the enzyme activities or afford complete protection of cellular structures against deformation, it apparently could eliminate oxygen radicals and prevent peroxidative reactions.