AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
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Relationship between Organic Aerosol Composition, In Vitro Oxidative Potential and In Vivo Airway Hypersensitivity
Jianhuai Ye, Sepehr Salehi, Michelle North, Anjelica Portelli, Chung-Wai Chow, ARTHUR CHAN, University of Toronto
Abstract Number: 223 Working Group: Health Related Aerosols
Abstract Epidemiological studies have shown that particulate matter (PM) is associated with the incidence, morbidity and mortality of cardiopulmonary diseases. Secondary organic aerosol (SOA) is a major component of ambient PM. Here we measure the in vitro oxidative potential of SOA using dithiothreitol assay and study the in vivo pulmonary effects on mice exposed to lab-generated SOA. SOA from oxidation of naphthalene (N-SOA) was found to exhibit high levels of oxidative potential compared to other SOA types. The contribution of individual compound groups (quinones, peroxides) to overall oxidative potential is investigated. Healthy 8-10 weeks old female mice were exposed for 1 hr/day for 3 consecutive days to N-SOA, maintained at levels similar to street-level concentrations during exposures. Pulmonary function and methacholine-responsiveness were assessed 24 hours after the final exposure. Daily exposures to N-SOA increased total respiratory resistance to methacholine when compared to control filtered-air mice, and in a dose-dependent manner. However, the total and differential leukocyte counts in the broncho-alveolar lavage fluid were similar in all experimental groups, and histological staining showed no signs of cell recruitment, suggesting that increase in airway responsiveness was not associated with airway inflammation. Further studies will investigate non-inflammatory pathways causing airway hypersensitivity and the relationship between N-SOA composition, in vitro oxidative potential and airway hypersensitivity.