BIOLOGICAL DOSIMETRY IN DIFFERENT COMPARTMENTS OF THE RESPIRATORY-TRACT AFTER INHALATION OF RADON AND ITS DAUGHTERS

The aim of this study was to develop new assays for local dosimetry in the different compartments of the rat lung after inhalation of radon and its daughters under different exposure conditions. Sensitivity of these assays was compared with assays described previously for trachea l epithelia] cells (TEC) and pulmonary alveolar macrophages (PAM). The incidence of micronuclei in TEC or PAM after cell proliferation induc ed by in vivo acute ozone exposure appeared to be the most sensitive m ethod if proliferating cells only are taken into account. Proliferatin g cells were identified by immune-staining after labelling with 5-brom o-2'-deoxyuridine in vivo. This method can also be applied to bronchia l and bronchiolar epithelial cells by using similar histochemical meth od. Thus, a new assay is proposed which could be used in the same anim al to perform sensitive biological dosimetry from the trachea to the a lveoli along the lung tracheo-bronchial tree.