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Simultaneous Exposure to Multiple Air Pollutants Influences Alveolar Epithelial Cell Ion Transport
Citation:
LAGIER, A. J., N. D. MANZO, AND J. A. DYE. Simultaneous Exposure to Multiple Air Pollutants Influences Alveolar Epithelial Cell Ion Transport. Presented at 2009 Annual Society of Toxicology meeting, Baltimore, MD, March 15 - 19, 2009.
Impact/Purpose:
This abstract reports on the changes to cell homeostasis elicited by exposing alveolar epithelial cells to combinations of pollutants, i.e. diesel exhaust particles and ammonia.
Description:
Purpose. Air pollution sources generally release multiple pollutants simultaneously and yet, research has historically focused on the source-to-health linkages of individual air pollutants. We recently showed that exposure of alveolar epithelial cells to a combination of particulate matter-associated metals resulted in greater epithelial cell damage than cells exposed to each metal individually. The goal of the current study was to further assess how mixtures of air pollutants interact to alter alveolar epithelial cell health. Method. Confluent murine LA-4 cells were loaded with BCECF-AM, a cell-permeant fluorescent intracellular pH indicator. LA-4 cells were subsequently treated with increasing concentrations (0 – 100 μg/cm2) of insoluble particles, either vehicle-emitted diesel exhaust particles (DEP) or carbon black (CB), individually or in combination with an acidic insult, i.e. 100 mM ammonium chloride or acetate, a soluble toxicant associated with lung injury. Cells were treated for 15 minutes, washed and changes in fluorescence between pre- and post-exposure were assessed. Results. LA-4 cells exposed to DEP or CB individually had no significant change in fluorescence, while LA-4 cells exposed to ammonium alone had a significant loss in fluorescence, an indicator of altered intracellular pH. Alternatively, LA-4 cells exposed to increasing concentrations of DEP, but not CB, in combination with ammonium had significantly less fluorescence loss than cells treated with ammonium alone. Conclusions. Data presented here indicates that DEP alters the intracellular ion transport elicited by ammonium and suggests that DEP likely prevents mechanisms necessary to protect alveolar epithelial cells from ammonium toxicity. In this regard, this study exemplifies the importance of using combinations of pollutants for assessing effects of air pollution on health. (Abstract does not reflect USEPA policy)