Effect of Ammonium Bisulfate and Carbon Black Particles Inhaled Alone and in Combination on Airway Reactivity in Actively Sensitized Brown-Norway RatsEPA Grant Number: R826778
Title: Effect of Ammonium Bisulfate and Carbon Black Particles Inhaled Alone and in Combination on Airway Reactivity in Actively Sensitized Brown-Norway Rats
Investigators: Benson, Janet M.
Current Investigators: Benson, Janet M. , Barrett, Edward G. , Bice, David E. , Cheng, Yung-Sung , Powell, Quint H.
Institution: Lovelace Biomedical & Environmental Research Institute
Current Institution: Lovelace Respiratory Research Institute
EPA Project Officer: Hunt, Sherri
Project Period: October 1, 1998 through September 30, 1999 (Extended to December 30, 2000)
Project Amount: $199,035
RFA: Health Effects of Particulate Matter and Associated Air Pollutants (1998) RFA Text | Recipients Lists
Research Category: Air , Health Effects , Particulate Matter
A growing body of evidence suggests that relatively small, acute increases in the concentrations of airborne particles above the National Ambient Air Quality Standard may be linearly associated with increases in morbidity and mortality in urban populations. The purpose of the research outlined in this proposal is to determine the relationship between increases in airborne aerosol mass concentrations of three models of major components of PM10, ammonium bisulfate, carbon black (a surrogate for fine soot particles), and ammonium bisulfate-coated carbon black, and changes in pulmonary function and airway hyperreactivity, in allergen sensitized Brown-Norway rats. Specifically, we will investigate the influence of the three inhaled pollutant particle types (particle size 0.1 mm) on pulmonary function and airway reactivity in allergen-sensitized male Brown-Norway rats, a rodent model for human extrinsic asthma. We hypothesize that, of the three particle types, acutely inhaled ammonium bisulfate-coated carbon black particles will give a greater airway response than the sum of the responses induced by inhalation of either ammonium bisulfate or carbon black particles alone.
Groups of 54 adult male ovalbumin-sensitized rats will be used. After baseline pulmonary function and airway responses to ovalbumin and acetylcholine have been measured, the rats will be exposed in a whole-body inhalation chamber for 6 hours to ammonium bisulfate, carbon black, and ammonium bisulfate coated carbon black particles. Respiratory function and airway challenges will be performed on groups of 10 rats 1?2, 6?8, and 24 hours alter. Groups of 8 rats each will be sacrificed at the same time points to evaluate the extent of inflammation produced. Mean values of total pulmonary resistance, and dynamic lung compliance before and after ovalbumin challenge and the concentration of acetylcholine that increases pulmonary resistance to 200% of control will be calculated for each group. Group differences will be calculated using multivariate analysis of variances, adjusted for multiple comparisons. If statistically significant changes in pulmonary resistance or dynamic lung compliance and airway reactivity in response to allergen specific and nonspecific challenge are not observed, for further acute exposure studies will be conducted and we will proceed with subchronic exposures.
It is expected that the ammonium bisulfate particles will produce greater airway effects than either ammonium bisulfate or carbon black particles alone. These studies will result in a better understanding of the importance of particle chemistry and combined versus single exposure in influencing pulmonary function, airway hyperreactivity, and susceptibility to allergen-specific and nonspecific airway challenge.
Improvement in Risk Assessment or Risk Management: These data will better define pollutant particle types that may affect the incidence of asthma attacks and help focus engineering controls and regulatory standards to reduce levels of these emissions.