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Activation of respiratory epithelial cells by wood smoke particles persists beyond immediate exposure.
Citation:
SOUKUP, J. M., L. A. DAILEY, AND A. J. GHIO. Activation of respiratory epithelial cells by wood smoke particles persists beyond immediate exposure. Presented at American Thoracic Society (ATS) Meeting, Denver, CO, May 13 - 18, 2011.
Impact/Purpose:
This is an abstract summarizing a presentation to be provided at the American Thoracic Society (2011).
Description:
The biological effect of particles on epithelial cells involves, in part, oxidant generation and a cascade of reactions culminating in inflammatory mediator release. Whether there is an immediate short-lived activation or continued persistent response of the cells to the particles has not been clearly established.. We tested the postulate that respiratory epithelial cells exposed to wood smoke particles would demonstrate increased mediator release and oxidative stress following re-plating and propagation of the cells for two generations post initial particle exposure. Wood smoke particles were mechanically disrupted from the stainless steel chimney above a Quadrafire 3100 woodstove burning red oak wood. BEAS-2B cells grown to confluence (G-l) in 75 cm2 flasks were treated for 18 hrs with the wood smoke particles at 0, 50, and 100ug/ml in KGM Gold. Supernatant from these flasks was collected for analysis of IL-8 release and the flasks were then used to seed another set of flasks as well as a 96 well white walled plate. The flasks were grown to confluence and the process repeated twice. Oxidant generation of BEAS-2B cells exposed to wood smoke particles (WS-PM) was assessed using a fluorescent dye, dichlorofluorescein diacetate (DCF) at 20 uM, over the course of 4 hrs. Cell viability was assayed using trypan blue dye exclusion and was always >95%. IL-8 release for 50 and 100ug/ml WS-PM increased in all three generations when expressed as a ratio to unexposed cells (1.04+/-0.08 and 1.27+/-0.28 for G-l, 1.47+/-0.85 and 2.36+/-0.93 for G-2 and 1.60+/-0.93 and 1.57+/-0.64 for G-3). Similarly, DCF fluorescence for 50 and 100ug/ml WS-PM increased in all three generations when expressed as a ratio to unexposed cells (2.85+/-0.64 and 3.65+/-0.25 for G-1, 1.13+/-0.30 and 1.16+/-0.01 for G-2, and 1.36+/-0.23 and 1.20+/-0.21 for G-3). The persistence of inflammatory mediator generation and oxidant stress for two generations of cells beyond the initial exposure supports a postulate of continued cell response to the particle. (Abstract does not reflect EPA policy).