Sample Characterization of Automobile and Forklift Diesel Exhaust Particles and Comparative Pulmonary Toxicity in Mice

• Published in: Environmental health perspectives 2004-06, Vol.112 (8), p.820-825
• Main Authors: Singh, Pramila, DeMarini, David M., Colin A. J. Dick, Tabor, Dennis G., Ryan, Jeff V., Linak, William P., Kobayashi, Takahiro, Gilmour, M. Ian
• Format: Article
• Language: English
• Subjects: Air pollution; Allergies; Animals; Asthma; Carbon; Carcinogens, Environmental - toxicity; Cytokines; Cytokines - biosynthesis; Cytokines - drug effects; Diesel exhaust; Endotoxins; Engines; Female; Forklifts; Gasoline - toxicity; Inflammation; Lung - drug effects; Lung - immunology; Lung - pathology; Lungs; Mice; Motor Vehicles; Particle Size; Particulate emissions; Particulate matter; Reference Values; Reproducibility of Results; Vehicle Emissions - toxicity
• ISSN: 0091-6765; 1552-9924
• DOI: 10.1289/ehp.6579

Two samples of diesel exhaust particles (DEPs) predominate in health effects research: an automobile-derived DEP (A-DEP) sample and the National Institute of Standards Technology standard reference material (SRM 2975) generated from a forklift engine. A-DEPs have been tested extensively for their effects on pulmonary inflammation and exacerbation of allergic asthmalike responses. In contrast, SRM 2975 has been tested thoroughly for its genotoxicity. In the present study, we combined physical and chemical analyses of both DEP samples with pulmonary toxicity testing in CD-1 mice to compare the two materials and to make associations between their physiocochemical properties and their biologic effects. A-DEPs had more than 10 times the amount of extractable organic material and less than one-sixth the amount of elemental carbon compared with SRM 2975. Aspiration of 100 μg of either DEP sample in saline produced mild acute lung injury; however, A-DEPs induced macrophage influx and activation, whereas SRM 2975 enhanced polymorphonuclear cell inflammation. A-DEPs stimulated an increase in interleukin-6 (IL-6), tumor necrosis factor α, macrophage inhibitory protein-2, and the T H2 cytokine IL-5, whereas SRM 2975 only induced significant levels of IL-6. Fractionated organic extracts of the same quantity of DEPs (100 μg) did not have a discernable effect on lung responses and will require further study. The disparate results obtained highlight the need for chemical, physical, and source characterization of particle samples under investigation. Multidisciplinary toxicity testing of diesel emissions derived from a variety of generation and collection conditions is required to meaningfully assess the health hazards associated with exposures to DEPs.