Cytotoxic action of rat alveolar macrophages for ozone-exposed lung fibroblasts

The objective of this study was to determine if exposure of cultured rat lung fibroblasts to O3 would trigger a subsequent attack by rat alveolar macrophages (AM). Fibroblasts labeled with [3H]proline (3HPR) were exposed to O3 (0, 0.74, 1.35, 2.46 or 4.48 ppm) for 1 h. AM were added (5:1, AM: fibroblast) and after 2, 24, 48, 76 and 96 h of co-culture, loss of 3HPR was measured as an index of AM-induced injury. Fibroblasts exposed to O3 and co-cultured with AM lost significantly more 3HPR than without AM co-culture. The results suggest that O3 injury to the lung may be mediated in part through an attack by AM upon O3-injured fibroblasts.