Preliminary studies of the interaction between 239PuO2 and cigarette smoke in the mouse lung

The first study showed that mice could tolerate the proposed smoking regime for 3 months, with no ill health. The major difference found was a reduced growth rate in smoke- and sham-exposed mice relative to cage controls. After 3 months of treatment, histopathology and morphometry of lung sections found only slight smoke-induced changes, including a reduced proportion of alveolar space and an increased number of pulmonary alveolar macrophages (PAM) per unit area. Bronchopulmonary lavage showed that PAM from smoke-exposed mice were larger than those from sham-exposed or control mice and that an increased proportion of cells were binucleate. All mice in the second study were initially exposed to 239PuO2, then subsequently divided into three groups. Cigarette smoke exposure was shown to inhibit the removal of 239Pu from the lung; sham exposure had no effect. Smoke exposure also produced an increase and sham exposure a decrease in lung weights relative to those of controls. The latter was probably as a result of their lower growth rate. In current experiments it is likely that the group receiving 239PuO2, then smoke, will receive a higher lung radiation dose than those receiving 239PuO2 only. (author)