OZONE ADAPTATION IN MICE AND ITS ASSOCIATION WITH ASCORBIC ACID IN THE LUNG

We have previously shown that ozone (O3) adaptation occurred in rats after daily exposure to an "urban-type" concentration. The adaptation was positively associated with an excess of ascorbic acid (AA) in bronchoalveolar lavage fluid (BALF), suggesting that AA may play a role in the adaptation mechanism. This relationship was not seen at higher and more toxic exposures. The present work exposed mice to low and high levels of O3 to see if the adaptation?AA relationship is common among rodent species. Male CD-1 mice were studied during repeated 6-h/day exposures to 0.0 or 0.25 ppm O3 for 10 days and 10 days of recovery in air (experiment 1) and to 0.0, 0.5, or 1.0 ppm O3 for 5 days (experiment 2). Approximately 20 h after each daily exposure, groups of mice were randomly selected from each concentration type and examined for patterns of response. They were anesthetized (urethane, ip), intubated, and the lungs were lavaged with 37°C saline. BALF was assayed for cells, cell differential, protein, albumin, lactate dehydrogenase, lysozymes, N