Vitamin C reduces ischaemia-reperfusion-induced acute lung injury

Objectives: to evaluate vitamin C supplementation in the prevention of isch aemia-reperfusion il-Xi induced acute lung injury. Design: Sprague-Dawley mts (n = 6/group) were randomised into Control, I-R and I-X pretreated with vitamin C (3.3 g over 5 days). Ischaemia-reperfusio n injury was induced by 30 minutes infrarenal aortic cross-clamping and 120 minutes reperfusion. Methods: pulmonary microvascular injury was measured by broncho-alveolar la vage protein concentration, pulmonary neutrophil infiltration by tissue mye loperoxidase activity and bronchoalveolar lavage neutrophil counts. In a se cond experiment (n = 5/group) neutrophil respiratory burst activity was mea sured in Control and vitamin C groups. Results: ischaemia-reperfusion resulted in a significant increase in both m icrovascular leakage and pulmonary neutrophil infiltration as measured by b ronchoalveolar lavage protein concentration and pulmonary myeloperoxidase a ctivity respectively. Pretreatment with vitamin C significantly attenuated both microvascular leakage and neutrophil infiltration. Neutrophil respirat ory 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 attenuating n eutrophil respiratory burst activity.