You are here:
COMPARISON OF PULMONARY RESPONSES TO AUTOMOBILE-GENERATED AND NIST STANDARD REFERENCE MATERIAL DIESEL PARTICULATE EMISSIONS IN MICE
Citation:
Singh, P., C. A. Dick, J H. Richards, M. J. Daniels, AND M I. Gilmour. COMPARISON OF PULMONARY RESPONSES TO AUTOMOBILE-GENERATED AND NIST STANDARD REFERENCE MATERIAL DIESEL PARTICULATE EMISSIONS IN MICE. Presented at Society of Toxicology 42nd Annual Meeting, Salt Lake City, Utah, March 9-13, 2003.
Description:
COMPARISON OF PULMONARY RESPONSES TO AUTOMOBILE-GENERATED AND NIST STANDARD REFERENCE MATERIAL DIESEL PARTICULATE EMISSIONS IN MICE. P. Singh1, C.A.J. Dick2, J. Richards3, M.J. Daniels3, and M.I. Gilmour3. 1NCSU, Raleigh, NC, 2UNC, Chapel Hill, NC and 3 USEPA, ORD, NHEERL, (ETD, Immunotoxicology Branch), RTP, NC.
Studies have shown that diesel exhaust particles (DEP) worsen respiratory diseases including allergic asthma. The adjuvant effects of DEP in the airways have been widely reported; however, the precise mechanisms of these effects remain ill defined. It is known that the composition of DEP may change with variations in conditions under which they are generated or collected. We hypothesized in this study that two different DEP samples, generated and collected under different conditions, would produce different levels of pulmonary toxicity. CD-1 mice were intratracheally (IT) exposed to 25 or 100 mg of either automobile-generated DEP (A-DEP: dilution tunnel collection, from a 4 cylinder Isuzu engine) or standard reference material DEP (SRM-DEP: NIST SRM 2975, from a forklift) or saline, and brochoalveolar lavage (BAL) was performed 4 and 18 hr later. Both samples produced increased total inflammatory cells with only a moderate increase in microalbumin and total protein in the BAL fluid. SRM-DEP produced 4-5 fold greater increase in neutrophil influx and greater depletion of total antioxidant capacity in the BAL fluid than A-DEP. Both the low and the high doses of A-DEP increased MIP-2 and IL-6, while only the high dose of SRM-DEP increased levels of these proinflammatory cytokines. By contrast, TNFa and N-acetyl glucosamine were significantly increased only by the A-DEP. Percentages of extractable organic material (hydrocarbons) in the two DEP samples were determined by dichloromethane extraction followed by gravimetric analyses. A-DEP was composed of 60-71% hydrocarbons, while SRM-DEP was composed of 1.6-6% hydrocarbons. We suggest that the observed differences in proinflammatory profiles are related to the disparate amounts of organic chemical constituents in the two DEP samples. (Supported by NIH grant # ES11245-01) (This abstract does not reflect EPA policy.)