Rat lung recovery from 3 days of continuous exposure to 0.75 ppm ozone

The present study investigated the inflammatory responses and enzyme levels in lungs isolated from male Wistar rats after 3 d of continuous exposure to 0.75 ppm ozone and following 4 d of recovery in air. These times are associated with maximal proliferation of the alveolar type II epithelium and their subsequent transformation to new type I cells. Immediately following ozone exposure, bronchoalveolar lavage demonstrated neutrophil accumulation that was no longer present 4 d later. The number of lavaged macrophages was also found to be increased immediately following ozone exposure, and remained elevated at 4 d postexposure. Whole‐lung determinations of key enzymes involved in energy generation (succinate oxidase) and maintenance of lung NADPH and reduced glutathione were corrected for changes in cell number, by use of lung DNA measurements. Immediately following ozone exposure succinate oxidase (SOX), glucose‐6‐phosphate (G6PD), and 6‐phosphogluconate (6PGD) dehydrogenise activities per milligram DNA wer...