Protective effect of ischemic preconditioning on small intestinal ischemia-reperfusion injury in rats

Protective effect of ischemic preconditioning on small intestinal ischemia-reperfusion injury in rats was investigated. Additionally, changes in endogenous neurotransmitter calcitonin gene-related peptide (CGRP) release in response to rat small intestinal preconditioning were examined. (1) In in vivo experiments, 30 min of small intestinal ischemia followed by 60 min of reperfusion (IR) caused an increase in wet weight/dry weight, dehydrogenase activity and malondialdehyde content in plasma. Preconditioning induced by 3 cycles of 8 min ischemia and 10 min reperfusion alleviated or eliminated above changes. There were no significant changes in CGRP level in plasma in IR and preconditioning groups as compared with the control group. (2) In in vitro experiments, superior mesenteric artery (SMA) was isolated and mounted onto a cannula attached to a perfusion apparatus. Superior mesenteric vein was exposed and incubated for collection of effluents. Intestines were perfused with K-H buffer at a constant temperature and pressure for 10 min. Preconditioning (3 cycles of 8 min occlusion of SMA and 10 min of reperfusion) resulted in a significant CGRP release in effluents in isolated intestinal model. These results suggest that ischemic preconditioning has protective effects on small intestinal ischemia/reperfusion injury, and has a significant effect on CGRP release.