DNA damage in lung cells after radon exposure detected by the comet assay

The comet assay was applied to measure DNA breaks and oxidised bases in fre shly isolated alveolar macrophages and epithelial type II cells from the ra t lung. The cells were exposed to radon for 60 min. Radon exposure was esti mated at 1.25-2.45 MBq.h.m(-3). Strand breaks were significantly elevated a bove the background level after irradiation of epithelial type II cells. In contrast, no strand breaks were induced in alveolar macrophages, but a hig h level of oxidised bases, mostly purines, was found. Alveolar macrophages and epithelial type II cells freshly isolated from the rat lung provide an exceptionally suitable cell model for investigation of potential hazards of air-borne environmental contaminants.