Lack of protection by ascorbic acid from lethality resulting from exposure to 1 atm O2

The role of ascorbic acid in protecting animals against the toxic effects of exposure to 1 atm. of O2 was examined. The mean time until death resulting from exposure to one atm. O2 was not different in rats treated intraperitoneally 3 times per day with 1.5 g/kg ascorbic acid compared to saline injected controls. Exposure of rats to one atm. O2 for 48 hr did not alter ascorbic acid or non-protein thiol concentration in lung or liver compared to room air controls. Lung ascorbic acid concentration was markedly depressed in guinea pigs fed an ascorbic acid-deficient diet for 6 days prior to O2 exposure. However, the mean time until death of ascorbic acid-deficient guinea pigs did not significantly differ from those fed an ascorbic acid-supplemented diet. Exposure to one atm. O2 of guinea pigs fed an ascorbic acid-deficient diet or an ascorbic acid-supplemented diet failed to decrease the concentration of ascorbic acid or of non-protein thiol in lung. Results from this study do not support an involvement of ascorbic acid in protection from pulmonary oxygen toxicity.