Protective Effect Of Ischemic Preconditioning Combined With Ischemic Postconditioning On Lung Ischemia Reperfusion Injury

Objective:To observe the change of the pulmonary water index(W/D) tissue myeloperoxidase (MPO) and superoxide dismute(SOD) activity, tissue malondialdehyde (MDA) content and analyze effect of ischemic preconditioning combined with ischemic postconditioning during lung ischemia reperfusion injury. And then, to discuss cumulative and protective effect of ischemic preconditioning combined with ischemic postconditioning during lung ischemia reperfusion injury, and to provide more available method that can less on lung ischemia reperfusion injury. Methods:By copying the rat model of lung ischemic reperfusion injury, Forty male Sprague Dawley adult rats were randomized to receive, sham-operation group(Sham), ischemia-reperfusion group(IR), ischemic preconditioning group (IPre), ischemic postconditioning group(IPost), combined ischemic preconditioning and ischemic postconditioning goup (IPre+IPost),(n=8in each group). After120-min reperfusion, the pulmonary water index (W/D), tissue myeloperoxidase (MPO) and superoxide dismute(SOD) activity, tissue malondialdehyde(MDA) content and morphologic changes were analyzed respectively. The statistical software package SSPS17.0was used. One-factor analysis of variance, Student-Newman-Keuls test and Spearman were used for quantitative date analysis, and a=0.05was taken as test criterion. P value that were less than0.05were considered statistical significance. Results:The study group showed the tissue levels of the pulmonary water index (W/D) and tissue myeloperoxidase (MPO) activity and tissue malondialdehyde (MDA) content were markedly lower in group IPre+IPost than IPre group and IPost group(P<0.05); the superoxide dismute(SOD) activity were markedly higher in group IPre+IPost than IPre group and IPost group(P<0.05); Histological examination showed that the lung injury in group IPre+IPost was less than IPre group and IPost group. SOD、MDA and MPO in group IPre+IPost had positive correlation with IPre group, SOD、MDA and MPO in group IPre+IPost had positive correlation with IPost group. After120min reperfusion, differences were compared on hematoxylin and eosin(HE)-stained sections in each group. Sham group showed normal alveolar size, wall structural integrity, non-thickening, no obvious hyperemia, edema and inflammatory cell infiltration under light microscope. IR group showed alveolar dilatation and congestion unequal alveolar size, a lot of red blood cells and edema fluid in alveolar lumen, alveolar wall thickening, widening the interval, pulmonary edema, inflammatory cell infiltration under light microscope. The degree of pathological damage was similar between IPre group and IPost but the degree of pathological damage was less in the two groups than IR group. The pathologic changes appeared in the red blood cells and edema fluid of alveolar cavities, alveolar wall thickening, widening the interval, pulmonary edema, neutrophil infiltration. Conclusion:1.This study indicated that better cumulative and protective effect of lung could be achieved with the use of combined ischemic preconditioning and ischemic postconditioning, IPre+IPost group further attenuated lung ischemia reperfusion injury, by reducing oxidative reactions, inhibiting the release of inflammatory factors and neutrophils immigration.2.There weren’t significant difference between IPre group and IPost group. IPre、IPost、IPre+IPost can protect the Lung Ischemia Reperfusion Injury in rats and IPre+IPost is more effective.