Unscheduled DNA synthesis in tracheal epithelial cell cultures

Abstract

An in vitro method has been established for the isolation and culture of tracheal epithelial cells for the evaluation of chemically induced genotoxicity using an unscheduled DNA synthesis assay. Cell cultures were derived from the Wistar albino rat and the golden Syrian hamster. Epithelial cells were isolated with protease type XIV for 16 hr and allowed to attach for 24 hr on collagen-coated coverslips in multi-well plates. Cells were exposed to the experimental carcinogens benzo[ a]pyrene (metabolism-dependent) and methylmethanesulphonate (direct acting) for 24 hr. Benzo[ a]pyrene and methylmethanesulphonate induced DNA repair in cultures isolated from hamsters, whereas only methylmethanesulphonate induced unscheduled DNA synthesis in rat tracheal epithelial cells, thus indicating the lack of metabolic activation in the rat cultures. These results could indicate the suitability of this culture system for the evaluation of airborne carcinogens.