DOSE REPARTITION IN ALVEOLI, ALVEOLAR DUCTS, AND BRONCHI OF RATS EXPOSED TO RADON AND ITS PROGENY, PRELIMINARY-RESULTS

Rats were exposed to ozone (2 mu L/L) for 5 h to increase micronuclei formation in the different lung compartments one week after local irra diation. Animals were exposed to either radon and its progeny (300 and 1000 WLM) or local lung external irradiation using gamma rays from co balt-60 (7.5 Gy). Animals were administered 5-bromo 2'deoxyuridine 18 and 12 h before to label post replicative cells. They were killed 36, 48, and 60 h after the beginning of the ozone exposures. Alveolar macr ophages (AM) were recovered by lavage of the left lobe and the right l obes were fixed for histological studies using confocal microscopy. Mi cronuclei measurements in AM provided only an estimate of mean dose 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. Copyright (C) 1996 Elsevier Science Ltd.