Protective effects of N-acetylcysteine against lung ischemia-reperfusion injury in rats.

Objective To investigate the protective effects of N-acetylcysteine against experimental lung ischemia-reperfusion(I/R)injury.Methods Thirty sprague-dawley rats were randomly divided into 3 groups(n=10 each):sham-operated group,I/R group and N-acetylcysteine-treated I/R group(NAC group).The left lung of rat was subjected to ischemia for 1 hr,followed by reperfusion for 2 hrs,to induce a lung I/R injury model.The rats of the NAC group received N-acetylcysteine(200 mg/kg)intraperitoneally 1 hr before ischemia.After reperfusion,the left lung was removed for the detection of the lung wet/dry ratio(W/D),thesuperoxide dismutase(SOD)activity,the myeloperoxidase(MPO)activity and the malondialdehyde(MDA)content.The pathological changes were also observed under light microscopes and the index of quantitative assessment(IQA)of histological lung injury was calculated.Results The W/D of lung and the IQA of I/R group were significantly higher than those of the sham-operated group(P0.01).The administration of N-acetylcysteine markedly reduced the indexes above(P0.01).The pathologic examination displayed that the lung tissue structure was normal and there was no congestion in the sham-operated group.The lung tissue structure of the I/R group was nearly normal but there were more congestion,interstitial inflammatory infiltration and edema than the NAC group.MDA and MPO in the I/R group were significantly higher and the SOD activity was lower than those in the sham-operated group(P0.01).Compared with the I/R group,N-acetylcysteine significantly reduced the MDA and MPO(P0.01),and increased the SOD activity(P0.01).Conclusion It is suggested that N-acetylcysteine could protect the lung against I/R injury possibly through its anti-oxidation effects and its inhibition of the activation of neutrophils.