Effect of ischemic postconditioning on alleviating lung ischemia-reperfusion injury in rats and its mechanism

Objective To observe the effect of ischemic postconditioning(IPC) on alleviating lung ischemia-reperfusion(IR) injury in rats and to explore its mechanism.Methods A total of 24 rats were randomly divided into 3 groups,8 in each: Sham-operation group(SO group),ischemia-reperfusion group(IR group),and ischemic postconditioning group(IPC group).In SO group,continuous infusion for 105 min;in IR group(as control group),45 min of ischemia,reperfusion for 60 min;in IPC group,ischemia for 45 min,infusion for 1 min,then ischemia for 1 min,repeating 5 times,and after that full restoration of perfusion for 50 min.The rats were killed to obtain the lung tissue.Malondialdehyde(MDA),superoxide dismutase(SOD),myeloperoxidase(MPO) level,lung wet / dry weight ratio(W/D) were detected by lung histomorphological examination.Results In IPC group,the alveolar exudates,red blood cells and white blood cells were fewer than those in IR group,which were observed under light microscope;and the polymorphonuclear leukocyte infiltration in lung interstitium was less.Compared with IR group,MDA,MPO levels and W/D in IPC group decreased,but SOD increased(all P0.05);compared with SO group,MDA,MPO levels and W/D in IPC and IR groups were all increased,SOD decreased(all P0.01).Conclusion The ischemic postconditioning has the effect of alleviating lung ischemia-reperfusion injury in rats and its mechanism is related to excessive production of oxygen free radicals after suppression of reperfusion.