Effects of asbestos on the random migration of rabbit alveolar macrophages.

The toxicity of sized and characterized chrysotile, crocidolite, and amosite preparations obtained from Dr. K. R. Spurny have been evaluated using alveolar macrophage (AM) migration inhibition assays and viability tests. These results have been compared with asbestos samples obtained from the National In? stitute of Environmental Health Sciences (NIEHS). These latter samples are designated chrysotile A (RT), crocidolite (RT), and amosite (RT). In addition, filter-isolated preparations of chrysotile A (RT) that consisted mainly of large nonphagocytosable fibers were also tested. Chrysotile (Spurny) and sonicated chrysotile A (RT) produced 50% migration inhibition at about 115 |xg/mL. Spurny crocidolite produced 50% migration inibition at about 340 (Jig/mL, whereas RT crocidolite produced 50% migration inhibition at about 230 |xg/mL. RT amosite caused 50% migration inhibition at about 180 p-g/mL, whereas Spurny amosite was inactive up to 500 |xg/mL. The large nonphagocytosable chrystile A (RT) fibers produced 50% migration inhibition at about 66 |xg/mL. This indicates that fibers can be toxic for AM through extracellular membrane contact. In general the results from the viability studies paralleled the migration inhibition observations. None of the asbestos preparations induced a burst in the hexose monophosphate shunt of BCG-immune AM at 1 mg/mL. BCG-immune AM were more susceptible to cell death than normal AM when incubated with chrysotile A (RT), amosite (RT) and zymosan. Migration inhibition induced by asbestos fibers probably reflects toxicity of the asbestos preparations and could play an important role in blocking normal alveolar clearance of inhaled particles.