PYRUVATE PREVENTS ISCHEMIA-REPERFUSION MUCOSAL INJURY OF RAT SMALL-INTESTINE

BACKGROUND: Since reactive oxygen intermediates (ROI, or free radicals ) have been implicated in the pathogenesis of ischemia-reperfusion inj ury of the small bowel, we evaluated the pretreatment effect of pyruva te, a 3-carbon compound recently shown to inhibit superoxide productio n, on reperfusion mucosal injury in the rat. METHODS: The small bowel of the ACI rat (n = 6) was divided into 2 5-cm segments, and 10 mt of a liquid diet containing pyruvate (0.32 g) or placebo (0.26 g) was ins tilled into the lumen of one of the segments for 10 minutes. The bowel was then made completely ischemic for 45 minutes by clamping the supe rior mesenteric artery, which was followed by 60 minutes of reperfusio n. RESULTS: The production of ROI in bowel biopsy samples, estimated b y luminol-enhanced chemiluminescence, was at least 80% decreased in th e segment containing pyruvate compared with placebo immediately after ischemia (time 0), and compared with 30 and 60 minutes of reperfusion (P <0.05 for each time point). After 60 minutes of reperfusion, the bo wel segment containing the placebo diet showed villus sloughing with d estruction of lamina propria and crypts, and mucosal neutrophil infilt ration had increased by 80%. Electron microscope evaluation revealed a reduction in number and size of microvilli, dilatation of intercellul ar spaces, and intracellular vacuoles. The bowel segment containing py ruvate showed the villi and crypts to be intact, without enhanced neut rophil infiltration. CONCLUSION: Pyruvate pretreatment of the rat smal l bowel inhibits postischemic reperfusion mucosal histologic injury, n eutrophil infiltration, and ROI production.