Effects of N-acetylcysteine on lung ischemia-reperfusion injury in rats

Objective: To observe the protective effect of N-acetylcysteine(NAC) on lung ischemia-reperfusion injury in rats by establishing models of lung ischemia-reperfusion.Methods: Thirty female SD rats were randomly divided into three groups of ten each: sham group(group A),left chest was opened and main bronchus and pulmonary artery and vein were isolated but not clamped.The lungs were ventilated for 165 min.Ischemia-reperfusion group(group B),left pulmonary hilum was isolated and clamped for 45 min.After declamping,the lungs were ventilated for 2 h.NAC group(group C),were injected NAC(200 mg·kg-1) intraperitoneally 30 min before anesthesia.All rats were killed at the end of the reperfusion.The blood were collected for the measurement of TNF-α.The left lung tissue were excised for microscopic examination and measurement of wet/dry weight(W/D) ratio,myeloperoxidase(MPO) activity,superoxide dismutase(SOD) activity and malondialdehyde(MDA) content.Results:(1)There were remarkable pathological manifestations of pulmonary injury in the group B.Compared with the group B,the pathomorphology changes of group C were ameliorated.(2) In group B,C,the W/D ratio,content of MDA and activity of MPO in lung tissue after reperfusion were significantly higher than those of group A(P0.05),the activity of SOD in lung tissue after reperfusion were significantly lower than that of group A(P0.05).Compared with group B,the W/D ratio,the levels of MDA and the activity of MPO were significantly decreased in group C(P0.05),the levels of SOD were significantly increased in group C(P0.05).(3)In group C,the content of TNF-α in blood after reperfusion were significantly lower than that of group B(P0.05).Conclusion: Injected NAC intraperitoneally before anesthesia protects the lungs against ischemia-reperfusion injury in SD rats in vivo.This protection is associated with the inhibition of infiltration and activation of neutrophils and the reduction of TNF-α.It is also associated with the cleaning of oxygen free radicals.