Avaliação de diferentes métodos de pós-condicionamento isquêmico na prevenção das lesões de reperfusão mesentérica

Abstract

Ischemic postconditioning have been recognized as effective in preventing reperfusion injury in situations of ischemia and reperfusion in various organs and tissues. However, it is not clear what would be the best way to accomplish it, since studies show wide variation method. The overall objective of this research was to evaluate the effect of two different methods of ischemic postconditioning in the process of mesenteric ischemia and reperfusion in rats; the specific objectives were to evaluate the effectiveness of ischemic postconditioning on local protection (intestine) in the process of mesenteric ischemia and reperfusion in rats, in addition to its efficacy in preventing remote reperfusion injury in the lungs and liver. 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 ischemic postconditioning with two alternating cycles of reperfusion and reocclusion, two minutes each; and Group C (10 rats), ischemia-reperfusion process interleaved by postconditioning by four alternating cycles of reperfusion and reocclusion of 30 seconds each. Finally, it was resected a segment of small intestine, 5cm proximal to the ileocecal valve, the left lateral lobe of the liver and caudal lobe of the right lung for histological analysis. We evaluated the results by Chiu et al. (1970) to the intestine, Takeda et al. (2003) to the liver and Sizlan et al. (2009) to the lung. The results were analyzed statistically using the nonparametric Kruskal-Wallis test, establishing a significance level of p<0.05. For this we used the program Bioestat 5.0. The analysis of the small bowel showed 2.8 in group A, 1.4 in group B and 1.4 in group C (p<0.05 between groups A and B; A and C; p>0.05 between groups B and C); in relation to the liver, there was obtained 1.8 average in group A, 1.7 in B, and 1.3 in group C (p> 0.05); the average of tissue damage on lungs was one to three groups (p> 0.05). The ischemic postconditioning was able to reduce the harm produced directly on the intestine, both with two cycles of two minutes and with four cycles of 30 seconds, however, it was unable to decrease injuries on liver in the animals subjected to mesenteric ischemia and reperfusion process. The research was unable to evaluate the efficacy of ischemic postconditioning on lungs, since the method of ischemia and reperfusion caused only mild injury in all groups.