You are here:
SUBCHRONIC EPISODIC EXPOSURE OF RATS TO DIESEL PLUS OZONE INDUCES MINIMAL CARDIOPULMONARY EFFECTS
Citation:
SCHLADWEILER, M., A. D. LEDBETTER, J. SHANNAHAN, G. WALLENBORN, A. NYSKA, D. MALARKEY, J. E. RICHARDS, H. TONG, R. B. DEVLIN, AND U. P. KODAVANTI. SUBCHRONIC EPISODIC EXPOSURE OF RATS TO DIESEL PLUS OZONE INDUCES MINIMAL CARDIOPULMONARY EFFECTS. Presented at Society of Toxicology Annual Meeting, Seattle, WA, March 16 - 20, 2008.
Impact/Purpose:
Since high ozone concentrations are often associated with increased traffic-related emissions, we postulated that long-term episodic exposure of rats to DE plus ozone would induce greater effects than exposure to individual components by themselves.
Description:
Diesel exhaust (DE) emissions contribute to near-road air pollution and have been shown to induce a variety of cardiovascular and pulmonary abnormalities in animals and humans. Since high ozone concentrations are often associated with increased traffic-related emissions, we postulated that long-term episodic exposure of rats to DE plus ozone would induce greater effects than exposure to individual components by themselves. We exposed male Wistar Kyoto rats (12-15 wks), nose-only, to resuspended bulk DE collected from the tail pipe of 30 kW Deutz engine (2.0 mg/m3), ozone (0.5 ppm) or combination of both, 5 h/dx1 d/wkx16 wks. Control rats were exposed to filtered air. A number of pulmonary and systemic markers of inflammation and injury were analyzed 2 d after final exposure. Cardiac performance and recovery from ischemia were analyzed using ex-vivo Langendorff perfusion system. Mild alveolar duct hyperplasia and inflammation were noted in all rats exposed to ozone, while particle laden macrophages were detected in DE-exposed rats. Both of these changes were apparent in rats exposed to DE plus ozone but without one exacerbating the other. The only effect noted on bronchoalveolar lavage fluid markers was a small increase in neutrophils in rats exposed to DE or ozone. This effect was diminished in rats exposed to DE plus ozone. Blood hemoglobin levels were higher whereas circulating lymphocyte decreased in rats exposed to either DE or ozone but not DE plus ozone. No differences in cardiac performance or ischemia-reperfusion recovery were apparent. These data suggest that subchronic episodic inhalation of diesel or ozone individually causes minimal pulmonary inflammation and mild systemic inflammation. This effect is minimized when the exposures occurs together. (Abstract does not reflect US EPA policy). Supported in part by EPA/UNC Cooperative Agreement #CT829471.