Vitamin C reduces ischaemia-reperfusion-induced acute lung injury

Objectives: to evaluate vitamin C supplementation in the prevention of ischaemia-reperfusion (I-R) induced acute hung injury. Design: Sprague-Dawley rats (N = 6/group) were randomised into Control, I-R and I-R pretreated with vitamin C (3.3 g over 5 days). Ischaemia-reperfusion injury was induced by 30 minutes infrarenal aortic cross-clamping and 120 minutes reperfusion. Methods: pulmonary microvascular injury was measured by broncho-alveolar lavage protein concentration, pulmonary neutrophil infiltration by tissue myeloperoxidase activity and bronchoalveolar lavage neutrophil counts. In a second experiment (n = 5/group) neutrophil respiratory burst activity was measured in Control and vitamin C groups. Results: ischaemia-reperfusion resulted in a significant increase in both microvascular leakage and pulmonary neutrophil infiltration as measured by bronchoalveolar lavage protein concentration and pulmonary myeloperoxidase activity respectively. Pretreatment with vitamin C significantly attenuated both microvascular leakage and neutrophil infiltration. Neutrophil respiratory burst activity was significantly reduced in the vitamin C group (13.02 m.c.f. ± 0.3) compared with Control (19.04 m.c.f. ± 1.9), P < 0.02. Conclusion: these data suggest that oral vitamin C therapy protects against ischaemia-reperfusion-induced acute lung injury, possibly by attentuating neutrophil respiratory burst activity.