An early marker of hyperoxic lung injury in the rat and its pharmacological modulation.

Of three possible early biochemical changes which were investigated in rats after hyperoxia, one was shown to be a useful marker of damage in this species. Mitochondrial oxygen uptake measured in lung homogenates has already been reported to be impaired after 24 h. With a purified mitochondrial fraction, we found significant impairment after only 3 h exposure to 100% oxygen. To our knowledge, this is the earliest significant change reported in this species. The antioxidants N-acetyl cysteine, dimethyl sulphoxide and allopurinol were found to ameliorate the injury. This suggests a possible link with the pulmonary damage and survival of rats in hyperoxia, which may be modulated also by antioxidant therapy.