You are here:
PULMONARY INJURY AND INFLAMMATION FROM REPEATED EXPOSURE TO SOLUBLE COMPONENTS AND SOLID PARTICULATE MATTER (PM)
Citation:
Schladweiler, M., A. D. Ledbetter, A. Nyska, P. S. Gilmour, D. C. Christiani, J H. Richards, R. H. Jaskot, W P. Watkinson, D L. Costa, J K. McGee, AND U P. Kodavanti. PULMONARY INJURY AND INFLAMMATION FROM REPEATED EXPOSURE TO SOLUBLE COMPONENTS AND SOLID PARTICULATE MATTER (PM). Presented at American Thoracic Society, San Diego, CA, May 20-25, 2005.
Description:
Pulmonary injury from acute exposures to PM and the role of soluble versus insoluble PM have received considerable attention; however, their long-term impacts are less well understood. This study compared pulmonary injury and inflammatory responses from repeated exposure to soluble and insoluble PM components. Male Wistar-Kyoto rats were exposed intratracheally (1/wk x 8 or 16 wks) to saline, Mount St. Helens ash (MSH; 2.3 mg/kg, no soluble metals), combustion-derived emission PM (EPM; 1.15 or 2.3 mg/kg; containing soluble zinc), saline-leachate of EPM, or zinc sulfate (33.4 g/kg; same level as in high dose EPM). Other animals received 2x the concentration of all components for 8 wks. Pulmonary and systemic changes were evaluated 2d later. Hematological parameters were not affected by EPM or zinc; there was a slight drop in circulating lymphocytes in MSH-exposed animals. Particle overload was clearly evident pathologically in MSH- and EPM-exposed animals at both time points. BALF total cells were increased in all groups including MSH with the largest increase in EPM high dose. Increases in both neutrophilic inflammation (MSH>EPM) and macrophages (EPM>MSH) were also observed. The inflammatory effects of EPM-leachate and zinc were comparable, though slightly less than the EPM high dose group. BALF protein, albumin, LDH and -glutamyl transferase activities were increased in all exposures (8 wks>16 wks; EPM high dose>MSH=EPM leachate=zinc). The 8 wks results were generally more severe than those of 16 wks despite dose equivalence. Thus, long-term repeated exposure to solid or soluble PM components can cause persistent lung injury/inflammation, and the dose-rate over time appears to be a significant factor. (Abstract does not reflect USEPA policy; supported in part by #CR829522 between EPA and UNC