Effects of intestinal ischemia-reperfusion on major conduit arteries

Intestinal ischemia-reperfusion (I-R) is a common and serious clinical cond ition associated with simultaneous remote organ dysfunction. The purpose of this study was to investigate the effects of intestinal I-R on the vasomot or functions of major conduit arteries. Anesthetized rabbits were randomly assigned to one of three groups: sham-operated controls (Group I), and one- hour intestinal ischemia with two-hour reperfusion (Group II) or four-hour reperfusion (Group III). The following mechanisms of vasomotor functions we re studied in abdominal aorta, superior mesenteric, renal, pulmonary, and c arotid arterial rings: (1) endothelial-dependent vasodilation response to a cetylcholine, (2) endothelial-independent vasodilation response to nitropru sside, (3) beta-adrenergic vasodilation response to isoproterenol, and (4) phenylephrine-induced vasoconstriction. Intestinal injury was quantified us ing malondialdehyde (MDA) concentration and wet-to-dry intestine weight rat io. Intestinal I-R did not affect the maximal responsiveness or the sensiti vity to acetylcholine, nitroprusside, and isoproterenol in all the vessels studied. The maximal contractile response to phenylephrine increased signif icantly in mesenteric artery in Group II, (227.1 +/- 15.1% vs 152.8 +/- 11. 7% in controls) (p < 0.05). Intestinal MDA concentration, a marker of oxida nt injury, increased from 39.87 +/- 9.41 nmol/g to 67.8 +/- 8.8 nmol/g in g roup II (p < 0.01), and to 94.8 +/- 7.56 nmol/g in Group III (p < 0.001). W et-to-dry intestine weight ratio increased from 3.62 +/- 0.12 to 4.28 +/- 0 .17 in Group II (p < 0.01), to 4.62 +/- 0.14 in Group III (p < 0.001). Thes e data indicate that although the intestines of the animals subjected to in testinal I-R are seriously injured, the smooth muscle relaxation of major c onduit arteries was not affected.