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SAMPLE CHARACTERIZATION OF AUTOMOBILE AND FORKLIFT DIESEL EXHAUST PARTICLES AND COMPARATIVE PULMONARY TOXICITY IN MICE
Citation:
Singh, P., D M. DeMarini, C. A. Dick, D. Tabor, J. V. Ryan, W P. Linak, T. Kobayashi, AND M I. Gilmour. SAMPLE CHARACTERIZATION OF AUTOMOBILE AND FORKLIFT DIESEL EXHAUST PARTICLES AND COMPARATIVE PULMONARY TOXICITY IN MICE. ENVIRONMENTAL HEALTH PERSPECTIVES. National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, NC, 112(8):820-826, (2004).
Description:
Abstract
Two samples of diesel exhaust particles (DEP) predominate in DEP health effects research: an automobile-source DEP (A-DEP) sample and the National Institute of Standards Technology (NIST) standard reference material (SRM 2975) generated from a forklift engine. A-DEP have been tested extensively for their effects on pulmonary inflammation and exacerbation of allergic asthma-like responses. In contrast, SRM 2975 has been tested widely for its genotoxicity. In the present study, we combined physical and chemical analyses of both DEP samples with pulmonary toxicity testing in mice to compare the two samples and to make associations between the physicochemical properties of these particulate samples and their biological effects. A-DEP had >10X more extractable organic material (EOM) and < 1/6 of the elemental carbon compared to SRM 2975. Aspiration of 100 mg of either DEP suspension produced mild acute lung injury and an increase in inflammatory cells in bronchoalveolar lavage fluid; however, A-DEP induced macrophage influx and activation, whereas SRM 2975 enhanced neutrophil influx. A-DEP stimulated an increase in IL-6, TNFa, MIP-2, and the Th2 cytokine IL-5, whereas SRM 2975 only induced significant levels of IL-6. Fractionated organic extracts of DEP did not alter responses in the lung. The disparate results obtained from these two DEP samples highlight the need for chemical, physical, and source characterization coupled with multi-disciplinary toxicity testing of DEP samples from a variety of generation and collection conditions.