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PHOTOCHEMICAL REACTIONS ENHANCE INFLAMMATORY RESPONSES IN HUMAN LUNG CELLS
Citation:
DOYLE, M., K. SEXTON, H. JEFFERIES, K. LICHTVELD, AND I. JASPERS. PHOTOCHEMICAL REACTIONS ENHANCE INFLAMMATORY RESPONSES IN HUMAN LUNG CELLS. Presented at Society of Toxicology, New Orleans, LA, March 06 - 10, 2005.
Description:
The chemistry of hazardous air pollutants has been studied for many years, yet little is known about how these chemicals, once interacted with urban atmospheres, affect healthy and susceptible individuals. During this study, environmental irradiation chambers (also called smog chambers) use natural sunlight to induce the natural photochemically stimulated transformations of environmental pollutants. These smog chambers have been used for more than 30 years to investigate and develop chemical mechanisms of species found in the atmosphere and used in regulatory air quality models. Smog chambers, coupled with an in vitro system (A549 cells), were used to investigate methanol, toluene, and 1,3-butadiene in combination with a synthetic urban smog mixture. The synthetic urban smog mixture is composed of 55 hydrocarbon species representative of the ambient air of an average city in the United States. Once released into the atmosphere, these air pollutants interact with hydroxyl radicals and ozone, which are created by photochemical processes, to produce many identified and unidentified products. Once these chemical reactions occur, the toxic potential of these atmospheric pollutants is currently unclear. In this study, A549 cells were exposed simultaneously to irradiated and non-irradiated chamber mixtures for five hours. Post exposure, adverse health effects were determined by measures of increased cellular stress (cytokine release) and cytotoxicity. Exposure to the photochemically generated products of 1,3-butadiene, toluene, and methanol induced increases in both cytotoxicity and IL-8 gene expression compared to 1,3-butadiene, toluene, or methanol alone. The smog chamber / in vitro exposure design was used to investigate the toxicity of chemicals after photochemical reactions and interactions with the urban atmosphere on healthy and susceptible individuals using representative in vitro samples. This research helps connect the gaps in the literature to explain the toxicity found from exposures to multiple environmental pollutants found in an urban atmospheric setting, and provides a way to obtain a more truthful estimate of toxicity of ambient releases of pollutants.