Xanthine oxidase contributes to lung leak in rats subjected to skin burn.

We found that rats subjected to thermal skin injury (skin burn) had increased serum xanthine oxidase (XO) activities, increased serum complement activation (decreased serum CH50 levels), increased erythrocyte (RBC) fragility, increased lung neutrophil accumulation, and increased lung leak compared to sham-treated rats. Treatment of rats with allopurinol (an XO inhibitor) not only decreased serum XO activity, but also decreased complement activation, RBC fragility, lung neutrophil accumulation, and lung leak abnormalities in rats subjected to skin burn. We conclude that XO may contribute to acute lung injury and a number of events associated with the development of acute lung leak following skin burn.