Effects of oxygen on pulmonary macrophages and alveolar epithelial type II cells in culture

Cultures of Chinese hamster lung fibroblasts and explants of 20-day-old rat lungs were exposed to 95% oxygen with 5% CO2 in vitro. The Chinese hamster cells had stopped dividing after 17 hours exposure and cell death occurred at a mean time of 67 hours (s.d. 15 hours). The rat lung explants showed macrophages moving over a monolayer of alveolar type II epithelial cells. Both cell types appeared to function normally for 24 hours but cell division in the type II cells was about 50% of control between 12 and 24 hours of exposure and virtually ceased after 26 hours. Cell death commenced after 4 days and was complete in 9 days. Macrophages divided freely in the control cultures but only one division was seen during exposure to oxygen and that occurred during the first 24 hours. Motility was reduced by 50% during the second day of exposure and stopped during the 3rd day. No live macrophages were seen after 4 days exposure. These culture systems appear very suitable for screening drugs for their protective effect against oxygen toxicity.