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MURINE PULMONARY MACROPHAGE EXPRESSION AND PRODUCTION OF TNFA AND MIP-2 AFTER EXPOSURE TO DIESEL EXHAUST PARTICLES (DEP) AND EXTRACTS
Citation:
Stevens, T., M. J. Daniels, AND M I. Gilmour. MURINE PULMONARY MACROPHAGE EXPRESSION AND PRODUCTION OF TNFA AND MIP-2 AFTER EXPOSURE TO DIESEL EXHAUST PARTICLES (DEP) AND EXTRACTS. Presented at Society of Toxicology Annual Meeting, New Orleans, MA, March 06 - 10, 2005.
Description:
DEP constitute an important fraction of particulate air pollution and have been shown to cause inflammation of the airways. The aim of this study was to investigate the inflammatory cytokine response of alveolar macrophages exposed to DEP and DEP-extracts. A murine alveolar macrophage cell line was incubated for 4 hours with varying doses of DEPs or DEP-extract (10 ug/ml, 50 ug/ml, or 150 ug/ml) as well as vehicle control and endotoxin (0.2 ug/ml, 1 ug/ml, or 5 ug/ml). After exposure, biochemical markers of cytotoxicity; lactate dehydrogenase (LDH), ATP production, and calcein levels were measured. Pro-inflammatory cytokine expression and production of TNF-? and MIP-2 were measured by real time PCR and ELISA respectively. Expression and production of TNF-? and MIP-2 were greatly increased in LPS-exposed macrophages indicating the ability of the cells to make these cytokines. Overall DEPs and their extracts showed no cytotoxicity by the ATP and calcein assays although LDH levels were increased in cell supernates. TNF expression and production was not affected by exposure to any of the DEPs or their extracts. MIP-2 production was greatly reduced after exposure to the highest concentration of any of the DEPs. In contrast, MIP-2 mRNA expression was increased in a dose dependent fashion compared to controls. These results confirm previous findings that in vitro particle exposures increase gene expression of cytokines but reduce the level of protein measured by immunoassay, either via quenching antigenic moieties or by interfering with the assay. This phenomenon should be considered while conducting in vitro experiments involving exposure to particulate matter. (Supported by CT829472. This abstract does not reflect EPA policy.)