Endotoxin treatment of adult rats before hyperoxic exposure significantly increases their survival rate in >95% O2 (J. Clin. Invest.61: 269, 1978). In this study, we wished to determine: (a) whether endotoxin would protect against O2 toxicity if it were administered after the animals were already in >95% O2 for 12-48 h; and (b) the relationship between the endogenous antioxidant enzymes of the lung and the protective effect of endotoxin treatment.
