Ischemia-reperfusion protects the rat small intestine against subsequent injury

Background. It has been suggested that multiple sublethal insults are commo nly associated with the development of multiple organ failure (MOF). The gu t is considered to be pivotal in the pathogenesis of MOF. This study invest igated the effects of repeated ischemia-reperfusion of the rat small intest ine. Methods. Groups of rats underwent 30 min of superior mesenteric artery occl usion or sham operation followed by 24 h of reperfusion. They then received an additional 30 min of superior mesenteric artery occlusion and 2 h of re perfusion or sham operation. Small intestine was examined for mucosal injur y, neutrophil infiltration, goblet cell number, and generation of the eicos anoids, prostaglandin E-2, and leukotriene B-4. Activation of neutrophils w as assessed in systemic venous blood. Results, Animals subjected to two insults of ischemia-reperfusion demonstra ted significantly less mucosal injury than animals undergoing one episode o f ischemia and 2 h of reperfusion, despite increased neutrophil infiltratio n, leukotriene B-4, and activated systemic neutrophils. Goblet cell number was elevated in animals 24 h after the fist ischemia-reperfusion insult and remained enhanced after the second episode of ischemia-reperfusion. Conclusions. The initial episode of ischemia-reperfusion caused an adaptive response associated with cytoarchitectural preservation following the subs equent insult. Increased mucus production was associated with mucosal prote ction. Nevertheless, repeated ischemia-reperfusion potentiated the local in flammatory response and the systemic activation of neutrophils.