The protective effects of intermedin 1-53 against lung ischemia-reperfusion injury in rats

Objective To investigate the protective effects of intermedin 1-53 on lung ischemia-reperfusion in-jury in rats and its possible mechanisms.Methods Rat models of lung ischemia-reperfusion were established.Seven-ty-two healthy Wistar rats were randomly divided into three groups:surgical control group(group C),ischemia-reper-fusion group(group IR)and intermedin 1-53 pretreated group(group D).At each of three time spots(45 min ischemia,60 min and 120 min reperfusion),every 8 rats from the groups were sacrificed,collected for plasma sample and the whole right lung.The plasma contents of malondialdehyde(MDA),and the activity of myeloperoxidase(MPO)in lung tissue were determined.The lung mRNAs of IMD and CL were determined by semi-quantitative RT-PCR.Histopatho-logical study of the lung tissue was also performed.Results The plasma contents of MDA and MPO activity in lung tissue were both significantly increased during reperfusion in group IR,while the mRNA expression of IMD and CL low-er than those in the other groups.Pretreatment with intermedin 1-53 could attenuate the abnormal changes induced by IR.Pathological examination showed that the IR induced injury was also ameliorated with intermedin1-53 pretreat-ment.Conclusion Intermedin 1-53 treatment before ischemia appeared to be antioxidative which protected the lungs against IR induced injury,possibly by suppressing PMN infiltration,reducing production of oxygen radicals and inhibit-ing formation of lipid oxide products.