title: Impact of the composition of combustion generated fine particles on epithelial cell toxicity: influences of metals on metabolism.
abstract: Inhaled airborne particulate matter (PM) represents a potentially significant health hazard to humans. Exposure to PM strongly correlates with pulmonary inflammation and incidences of severe respiratory distress, including increased hospital admissions for breathing disorders, asthma, emphysema, and chronic bronchitis. PM generated from the combustion of fuel oils and coals contain a number of water-soluble transition metals including Fe, V, and Zn. We have evaluated the impact of PM types with varying composition collected from the combustion of oils and coals on the health and metabolism of lung cell cultures. Three colorimetric assays (sulforhodamine B (SRB), Janus green, and MTT) have been adapted to quantify the impact of PM on rat lung alveolar type II epithelial cells (RLE-6TN cells). The PM toxicity metrics evaluated were inhibition of cell proliferation (SRB and Janus green) and inhibition of cellular metabolism (MTT). Cell proliferation is inhibited in a consistent dose-dependent manner by PM concentrations from 25 to 250 microg/ml. At a level of 100 microg/ml, oil-derived PM diminishes cell metabolism by as much as 40% relative to controls; the degree of inhibition is strongly dependent on PM particle size and metal content. Conversely, coal-derived PM at the same dosage diminishes cell metabolism by no more than 20% relative to controls. All three assays provide highly repeatable results and consistent toxicity rankings of the PMs evaluated. Overall, metabolic inhibition as measured by the MTT assay was deemed the most appropriate metric for PM toxicity, primarily due to its applicability with in vivo-like confluent cell monolayers.
authors.affiliation: Department of Agricultural and Biosystems Engineering, The University of Arizona, Room 403 Shantz Bldg., Tucson, AZ 85721, USA.
authors.forename: Carl D
authors.initials: CD
authors.lastname: Okeson
authors.forename: Mark R
authors.initials: MR
authors.lastname: Riley
authors.forename: Art
authors.initials: A
authors.lastname: Fernandez
authors.forename: Jost O L
authors.initials: JO
authors.lastname: Wendt
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D000818:Animals; D018929:Cell Culture Techniques; D002455:Cell Division / Q000187:drug effects*; D003031:Coal; D004847:Epithelial Cells / Q000187:drug effects / Q000502:physiology; D005648:Fuel Oils; D017745:Incineration; D019216:Metals, Heavy / Q000633:toxicity*; D010316:Particle Size; D011650:Pulmonary Alveoli / Q000166:cytology* / Q000187:drug effects / Q000473:pathology; D051381:Rats
chemical_list: D000393:Air Pollutants; D003031:Coal; D005648:Fuel Oils; D019216:Metals, Heavy