The role of reperfusion injury in occlusive intestinal ischemia of the neonate: malonaldehyde-derived fluorescent products and correlation of histology.

Oxygen free radical reperfusion products may play a critical role in neonatal occlusive intestinal ischemia. We report a comparative analysis of light microscopy- and malonaldehyde (MDA)-derived fluorescent products as a measure of lipid peroxidation in occlusive intestinal ischemia in the rat. Weanling rats (n = 25) underwent cross clamping of the common mesenteric artery followed by various intervals of reperfusion; blood was sampled from the common mesenteric vein and the ileum was simultaneously biopsied. Blind-light microscopic scoring of the ischemic intestine was used. Fluorescent products were extracted using a chloroform/methanol/acidic water solvent extraction and measured with a spectrophotofluorometer using excitation/emission wavelengths of 360 and 430 nm, respectively. A trend was observed with prolonged reperfusion. Accumulation of fluorescent products correlated directly with the interval of reperfusion. Graded intervals of vascular occlusion produced progressive intestinal injury, but light microscopic analysis was not a sensitive index to distinguish the influence of graded reperfusion intervals. These data confirm a role for both ischemia and reperfusion in occlusive intestinal injury in the neonate and suggest that MDA accumulation may be a sensitive index of the reperfusion component of such injury.