Effect of N-acetyl-L-cysteine on lung ischaemia reperfusion injury in a porcine experimental model.

Background: The purpose of the present study was to investigate the effect of N-acetyl-L-cysteine on lung ischaemia reperfusion injury.

Methods: Nineteen pigs were used. Group I (n = 5) underwent sham operation, group II (n = 7) 90-min left-lung ischaemia followed by 180-min reperfusion. In group III (n = 7) N-acetyl-l-cysteine was given (160 mg/kg) during ischaemia into the pulmonary artery. Lung-functional and haemodynamic parameters were measured; serum and lung tissue samples were obtained and analysed for interleukin-10 and tumour necrosis factor-alpha. At the end of the reperfusion bronchoalveolar lavage was carried out from the ipsilateral lung and analysis for total protein, phospholipase-A(2) and platelet-activating factor acetylhydrolase was carried out. Histological specimens were graded (0-3) for alveolar oedema, interstitial thickening and leucocyte infiltration. Statistical analysis was by means of one-way analysis of variance and Kruskal-Wallis test.

Results: There were no differences in haemodynamic parameters, serum and tissue interleukin-10 and tumour necrosis factor-alpha. Pulmonary compliance was decreased in groups II and III (P = 0.002 and P = 0.001, respectively) during ischaemia and reperfusion. Pulmonary vascular resistance was increased in group II (P = 0.051) during reperfusion. In group III total protein and platelet-activating factor acetylhydrolase were increased (P = 0.004 and P = 0.006, respectively) and phospholipase-A(2) was reduced (P = 0.002), indicating an indirect surfactant-protective effect. Interstitial thickening was excessive in group II (P = 0.001); however, alveolar oedema was reduced (P = 0.002) when compared with group III.

Conclusion: N-acetyl-L-cysteine when administered directly in the pulmonary artery showed no significant change in haemodynamic and functional lung parameters during ischaemia reperfusion; it does, however, have an indirect surfactant-protective effect.