Effects of in vitro ozone exposure on peroxidative damage, membrane leakage, and taurine content of rat alveolar macrophages.
The effects of ozone (10028156) on lipid peroxidation, membrane leakage, and taurine concentration of rat alveolar macrophages were studied in-vitro. Alveolar macrophages were isolated by pulmonary lavage from male Sprague-Dawley-rats and allowed to adhere to the bottom surfaces of culture flasks. They were exposed to 0 or 0.45 parts per million ozone for up to 60 minutes. The extent of recovery of macrophages from the flasks was determined. Cytotoxicity was assessed by determining cell viability using the trypan-blue exclusion assay. Recovery of total and adherent macrophages was sharply reduced after 30 minutes exposure to ozone. Cell viability was significantly decreased after 30 minutes exposure. Ozone induced an immediate increase in chemiluminescence of resting and zymosan stimulated macrophages that peaked after 15 to 30 minutes, decreasing thereafter. Total and sodium/potassium dependent ATPase activity decreased with increasing length of ozone exposure. Lipid peroxidation was significantly increased after 15 minutes exposure and increased linearly with increasing length of exposure. Leakage of protein, reduced glutathione, and oxidized glutathione was significantly increased after 30, 30, and 15 minutes exposure, respectively. Intracellular taurine concentration increased with increasing length of exposure, peaking at 30 minutes and decreasing thereafter. Extracellular taurine content increased with increasing length of exposure. Potassium leakage increased with increasing length of exposure. The increase could be correlated with the decrease in sodium/potassium dependent ATPase activity. The authors conclude that exposure of rat alveolar macrophages to ozone in-vitro results in time dependent alterations of cell function, membrane integrity, and viability that are probably due to a shift from bound to free intracellular taurine content.