Evaluation of Pulmonary Reperfusion Injury in Rats Undergoing Mesenteric Ischemia and Reperfusion and Protective Effect of Postconditioning on this Process

INTRODUCTION Some publications have demonstrated the presence of lung reperfusion injury in mesenteric ischemia and reperfusion (I/R), but under to diverse methods. Postconditioning has been recognized as effective in preventing reperfusion injury in various organs and tissues. However, its effectiveness has not been evaluated in the prevention of lung reperfusion injury after mesenteric ischemia and reperfusion. OBJECTIVE To evaluate the presence of pulmonary reperfusion injury and the protective effect of ischemic postconditioning on lung parenchyma in rats submitted to mesenteric ischemia and reperfusion. METHODS Thirty Wistar rats were distributed into three groups: group A (10 rats), which was held mesenteric ischemia (30 minutes) and reperfusion (60 minutes); group B (10 rats), ischemia and reperfusion, interspersed by postconditioning with two alternating cycles of reperfusion and reocclusion, for two minutes each; and group C (10 rats), ischemia and reperfusion interleaved by postconditioning with four alternating cycles of reperfusion and reocclusion of 30 seconds each. Finally, it was resected the upper lung lobe for histological analysis. RESULTS There were mild lung lesions (grade 1) in all samples. There was no statistical difference between groups 1 and 2 (P >0.05). CONCLUSION The mesenteric ischemia and reperfusion in rats for thirty and sixty minutes, respectively, caused mild reperfusion injury in lung. Postconditioning was not able to minimize the remote reperfusion injury and there was no difference comparing two cycles of two minutes with four cycles of 30 seconds.