In vivo oxidants and pulmonary inflammation.

Endotoxemia is used as a model of the adult respiratory distress syndrome in chronically instrumented awake sheep. The toxic effects of endotoxin may be mediated through inflammatory cells and the release of toxic oxidants. N-acetylcysteine (NAC) inhibits the in vivo effects of endotoxemia in chronically instrumented unanesthetized sheep. NAC also functions as a free radical scavenger in vitro. It is possible that the protective effects of pretreatment with NAC result from NAC's ability in vivo to protect against local oxidant injury.