Comparative effects of chrysotile asbestos fibers on lavaged pulmonary macrophages.

Chrysotile asbestos is cytotoxic to alveolar macropages. The mechanisms involved in initiating these cytotoxic events are poorly understood. Some investigators believe that the magnesium component of chrysotile is largely responsible. Others attribute the cytotoxicity to be the results of the chrysotile's physical characteristics. In this project, lavaged alveolar macrophages were used to provide a bioassay for detecting fiver uptake over time. In several separate experiments, two fiber populations differing significantly in both chemical and physical characteristics were added to cultured macrophages. The results suggest that ingestion of magnesium-leached fibers took place to a greater extent than unleached fibers, as evidenced by decreasing numbers of fibers attached to macrophages over time. The surface morphology of alveolar macrophages was not altered significantly by addition of either leached or unleached fibers. In addition, enzyme analysis of two marker enzymes, beta-glucuronidase and lactate dehydrogenase, were not significantly elevated, indicating lack of cytotoxicity over the three-hour period studied. This study provides information useful of future mechanistic investigations on cytopathologic interactions between macrophages and asbestos fibers.