Early pulmotoxic effects of oxygen on the rat alveolar type II epithelial cell.

Adult male rats were exposed to pure oxygen at atmospheric pressure for 12 and 24 h in order to examine the early pulmotoxic signs in alveolar type II epithelial cells. Lung specimens were processed for both light and electron microscopical examination. All changes were obvious, but less pronounced than in previous reports, and appeared only after 24 h of exposure. The type II cells showed dilation of the Golgi apparatus and changes in mitochondria. This experiment indicates that exposure to pure oxygen at atmospheric pressure for as short as 24 h, but not for 12 h, is adequate to induce subtle pulmotoxic changes in alveolar type II epithelial cells.