HYPEROXIC LUNG INJURY IN FISCHER-344 AND SPRAGUE-DAWLEY RATS INVIVO

Supplemental oxygen remains an important therapy for pulmonary insufficiency, despite the potential adverse effects of hyperoxic exposures. Recently, He et al. reported that hyperoxic ventilation more readily damaged isolated perfused lungs from Fischer-344 rats than from Sprague-Dawley rats (Am. J. Physiol. 259:L451), which correlates with the previously reported strain differences in hepatic responses to diquat-induced oxidant stress in vivo (J. Pharmaco. Exp. Ther. 235:172). We therefore examined the differences in hyperoxic lung injury in Fischer-344 and Sprague-Dawley rats in vivo. Adult male rats were exposed to > 95% O2 and were sacrificed after 24, 48, or 60 h. Control animals were maintained in room air. Dramatically greater increases in pleural effusions and bronchoalveolar lavage protein concentrations in response to hyperoxia were observed in the Fischer-344 rats than in the Sprague-Dawley rats (p < .05 at both 48 and 60 h for both measurements). Additionally, the glutathione concentrations in alveolar lining fluid decreased from 800 muM to 115 muM in Fischer-344 rats after 60 h of > 95% O2, but did not change in Sprague-Dawley rats. We conclude that the greater susceptibility of Fischer-344 than of Sprague-Dawley rats to hyperoxic lung injury in vitro reported previously also is observed in vivo and that this strain difference offers unique opportunities to study mechanisms of hyperoxic lung injury.