Role of oxygen derived free radicals in platelet activating factor induced bowel necrosis.

The mechanism of tissue and cell injury in ischaemic bowel necrosis is unclear. The present study investigated the role of oxygen derived free radicals in the development of bowel necrosis using injections of platelet activating factor (PAF) into the mesenteric vasculature. Animals were pretreated with allopurinol or superoxide dismutase together with catalase, before administration of PAF. Superoxide dismutase/catalase markedly improved the PAF-induced lesions, indicating that most of the intestinal damage after PAF injection is because of the release of oxygen radicals. The major source of oxygen radicals is xanthine oxidase, as allopurinol ameliorated small bowel lesions. Pretreatment with allopurinol produced a significant (p less than 0.01) preventive effect on PAF induced hypotension. In contrast, superoxide dismutase/catalase did not alter PAF induced hypotension. Superoxide dismutase/catalase pretreatment improved PAF induced haemoconcentration and leucopenia, while allopurinol showed no effect.