Evaluation of the release of mutagens and 1-nitropyrene from diesel particles in the presence of lung macrophages in culture.

The release and recovery of mutagenic activity and 1-nitropyrene from diesel particles phagocytized and cultured with lung macrophages were studied. The Ames Salmonella typhimurium plate incorporation assay was used to measure mutagenic activity. Quantitative analysis of 1-nitropyrene was performed with liquid chromatography/fluorescence analysis. The cytotoxicity and phagocytosis of diesel particles with and without fetal calf serum were evaluated to select exposure concentrations that resulted in minimal toxicity and maximal engulfment of particles by the macrophages. The diesel-particle exposure concentrations for the mutagenicity studies were 200 micrograms/ml in the absence of serum and 375 micrograms/ml in the presence of serum. Engulfment and incubation of diesel particles with lung macrophages resulted in the loss of considerable mutagenic activity (97-98%) and significantly less 1-nitropyrene (10-25%). These studies suggest that lung macrophages have the capability to metabolize mutagenic nitroaromatics found in diesel particles.