Assessment of progression of asbestosis in the sheep model by bronchoalveolar lavage and pulmonary function tests.

Abstract

To study the relationship between the results of bronchoalveolar lavage and pulmonary function tests during induction and progression of asbestosis, 3 groups of 6 sheep were exposed repeatedly by intratracheal injection to either saline (controls), low doses of Canadian chrysotile UICC asbestos (cumulative exposure 328 mg) (low-dose group), or high doses of the same fibers (cumulative dose 2282 mg) (high-dose group) until there was clear evidence of alveolitis from the lung biopsy specimens of all sheep of the high-dose group. During the course of this induction and for the following 8 mo. lung biopsies, bronchoalveolar lavage and pulmonary function tests were performed at 2 mo. intervals. At the time of initial alveolitis in the high-dose group there was no significant change in cellularity of the bronchoalveolar lavage fluid, but static lung compliance (Cst), vital capacity (VC), arterial O2 tension (PaO2) and diffusion capacity (DL/VA) were significantly lower than in the other groups. In the following months, as the alveolitis evolved into a fibrosing process, macrophages and neutrophils from the bronchoalveolar lavage fluid increased significantly and pulmonary function deteriorated. Proteins and enzymes in the bronchoalveolar lavage fluid also increased significantly in the high-dose group. The sheep model of asbestosis simple tests of pulmonary function correlate well with histological changes and changes in the bronchoalveolar lavage fluid in the course of the disease and can, apparently, be used to assess progression of asbestosis.