Dose repartition in alveoli, alveolar ducts and bronchi of rats exposed to radon and its progeny, preliminary results

Rats were exposed to 2 ppm ozone for 5 hours to increase micronuclei formation in the different lung compartments one week after local irradiation. Animals were exposed to either radon and its progeny (300 and 1000 WLM) or local lung external irradiation using gamma rays from cobalt-60 (7.5 Gy). Animals were administered 5-bromo 2'deoxyuridine 18 and 12 hours before to label post replicative cells. They were killed 36, 48 and 60 hours after the beginning of the ozone exposures. Alveolar macrophages (AM) were recovered by lavage of the left lobe and the right lobes were fixed for histological studies using confocal microscopy. Micronuclei measurements in AM did provide only mean dose estimate to the deep lung. Histological observations showed a nearly homogeneous irradiation by gamma rays whereas, heterogeneous irradiation seemed to occur after radon exposure with a gradual dose increase from alveoli to bronchi. Confocal microscopy/ Micronuclei/ Radon/ Ozone/ Pulmonary epithelial cells/ Alveolar macrophages/ Rats/ Gamma rays/ International Symposium on the Natural Radiation Environment, Montreal, 5-9 juin 1995