Too short cycles of postconditioning have no protective effect against reperfusion injury. Experimental study in rats.

Abstract

IntroductionIschemic postconditioning has been recognized as effective in the prevention of reperfusion injury in situations of ischemia and reperfusion in various organs and tissues. However, it remains unclear what would be the best way to accomplish it, since studies show great variation in the method of their application.ObjectiveTo assess the protective effect of ischemic postconditioning on ischemia and reperfusion in rats undergoing five alternating cycles of reperfusion and ischemia of 30 seconds each one.MethodsWe studied 25 Wistar rats distributed in three groups: group A (10 rats), which underwent mesenteric ischemia (30 minutes) and reperfusion (60 minutes); Group B (10 rats), undergoing ischemia (30 minutes) and reperfusion (60 minutes), intercalated by postconditioning (5 alternating cycles of reperfusion and ischemia of 30 seconds each one); and group C - SHAM (5 rats), undergoing only laparotomy and manipulation of mesenteric artery. All animals underwent resection of an ileum segment for histological analysis.ResultsThe mean lesions degree according to Chiu et al. were: group A, 2.77, group B, 2.67 and group C, 0.12. There was no difference between groups A and B (P>0.05).ConclusionIschemic postconditioning was not able to minimize or prevent the intestinal tissue injury in rats undergoing ischemia and reperfusion process when used five cycles lasting 30 seconds each one.

Short-interval postconditioning protects the bowel against ischaemia–reperfusion injury in rats

“…In the present study, the PC intervals (5, 10, and 20 seconds) were shorter than those in the studies by Nakamura et al. 15 and Rosero et al. 14 and SIPC was able to protect the bowel against reperfusion injury.…”

“…Nakamura et al. 15 also reported that short cycles of PC were not effective in preventing intestinal tissue injury in rats. In their study, they performed 5 cycles of 30 seconds of reperfusion interspersed by 5 cycles of 30 seconds of ischaemia.…”

Ischemic Postconditioning Assessment in the Liver of Rats Undergoing Mesenteric Ischemia and Reperfusion

“…This technique has already been proven as effective in intestinal I/R protection [9] , nevertheless, Nakamura et al [18] recently demonstrated that five cycles with a duration of thirty seconds each for IPC were not able to prevent reperfusion injury in rats. Failure to protect tissue through IPC using short cycles had already been published previously by Bretz et al [19] , who performed jejunal I/R in rabbits.…”

Importance of duration and number of ischemic postconditioning cycles in preventing reperfusion mesenteric injuries. Experimental study in rats

“…Nakamura et al 16 also showed no benefit in IPC employment using five cycles of reperfusion and ischemia lasting Importance of duration and number of ischemic postconditioning cycles in preventing reperfusion mesenteric injuries. Experimental study in rats could permit us to infer that perhaps a greater number of short cycles does not lead to a protective effect with IPC.…”

“…Rosero et al 14 Also showed no benefit in the use of IPC in intestinal ischemia and reperfusion Nakamura et al 16 , using five cycles of reperfusion and ischemia of 30 seconds each.…”