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RESPONSES OF CULTURED HUMAN AIRWAY EPITHELIAL CELLS TREATED WITH DIESEL EXHAUST EXTRACTS WILL VARY WITH THE ENGINE
Citation:
Madden, M. C., L. A. Dailey, J. Stonehuerner, AND D B. Harris*. RESPONSES OF CULTURED HUMAN AIRWAY EPITHELIAL CELLS TREATED WITH DIESEL EXHAUST EXTRACTS WILL VARY WITH THE ENGINE. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. Taylor & Francis Health Sciences, London, Uk, 66:2281-2297, (2002).
Description:
Epidemiologic evidence suggests that increased morbidity and mortality are associated with the concentrations of ambient air particulate matter (PM). Many sources contribute to the particulate fraction of ambient pollution, including diesel exhaust particulates (DEP). Diesel exhaust also contributes gas phase pollutants to the atmosphere, and gaseous co-pollutants may influence the toxicity of PM. The composition of diesel exhaust varies greatly dependent upon the engine load conditions as well as other factors. To determine if different diesel exhaust composition can affect lung cell responses, we examined the effect of diesel exhaust extracts derived from different engine loads on normal human bronchial epithelial cells (NHBE) in vitro. Diesel exhaust was collected into chilled impingers containing PBS. Cultured NHBE cells were treated with 0 to 500 g/ well of extract from ~0% engine load (termed low load or LL) or extract from ~75% engine load (termed high load or HL) for 24 hr. The HL extract was slightly cytotoxic at 500 g compared to controls as measured by 51Cr release. Production of the neutrophil chemotaxin interleukin-8 was decreased 4.7-fold in cells treated with 500 g LL extract, whereas cells treated with 500 g HL extract showed a 2.4 fold increase in IL-8 release. Production of the inflammatory and immune system mediator prostaglandin E2 (PGE2) was increased up to 2.5-fold in cells treated with HL extract, but unchanged with other treatment groups. Melittin stimulation of cells showed that the LL extract had an inhibitory effect on PGE2 release at 500 g. Differences in carbonyl content of the extracts were found by HPLC/MS, with the HL extract having more intermediate size carbonyls (i.e., with 6 to 9 carbons). The data suggest that the response of NHBE cells to treatment with diesel exhaust will vary dependent upon the constituent components of the exhaust.
Disclaimer: The research described in this article has been reviewed by the National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the Agency nor does mention of trade names or commercial products constitute endorsement or recommendation for use.