The use of cell and organ culture from the respiratory tract for testing chemicals.

For the toxicity testing of compounds using tissue from the respiratory tract, three types of in vitro cell or tissue culture systems are being developed from foetal Syrian hamster respiratory organs on day 15 of gestation. The first system, early-passage cell cultures of a mixed population obtained from foetal lungs, has been used frequently for the study of in vitro cell transformation. The clonal culture technique using these cells permitted the semi-quantitative determination of the toxicity of poly- or heterocyclic hydrocarbons in terms of the reduction in the number of surviving colonies. The second system, an explant culture technique using foetal tracheae, demonstrated the induction, by polycyclic hydrocarbons, of alterations such as hyperplasia, epidermoid metaplasia or dysplasia of mucociliary epithelia. The third system uses the cells of a permanent clonal epithelial cell line established from the foetal lung. These cells differentiated into a mucus-producing cell type in a medium supplemented with vitamin A and hormone. In order to observe general aspects of toxicity in these cells, they were exposed first to model substances such as sulphuric acid and potassium dichromate. After 24 hr of post-exposure incubation, the activities of membrane-bound and cytosolic enzymes, the amount of sialic acid released into the medium and cell survival were measured. Based on the results obtained so far, the potential value of each system is discussed.