You are here:
SYNTHETIC PARTICLES ENHANCE AIRWAY RESPONSES TO OVALBUMIN ANTIGEN IN BALB/C MICE
Citation:
Gavett, S H., N HaykalCoates, AND M I. Gilmour. SYNTHETIC PARTICLES ENHANCE AIRWAY RESPONSES TO OVALBUMIN ANTIGEN IN BALB/C MICE. Presented at SOT, San Francisco, CA, March 25 - 29, 2001.
Description:
SYNTHETIC PARTICLES ENHANCE AIRWAY RESPONSES TO OVALBUMIN ANTIGEN IN BALB/CJ MICE. S H Gavett, N Haykal-Coates, and M I Gilmour. Experimental Toxicology Division, NHEERL, ORD, USEPA, Research Triangle Park, NC
Levels of airborne particulate matter (PM) are positively correlated with asthmatic symptoms and hospitalizations for asthma. Transition metals associated with particles have been proposed to contribute to allergic inflammation and airway hyperresponsiveness. The objective of this study was to examine the contribution of specific metals associated with PM to these responses using chemically defined synthetic particles. The following particles were used in this study: 1) control carbon (C) particles (15% NH4Cl, 30% Na2SO4, 55% carbon core), and 2) carbon-zinc (CZn) particles (5% zinc sulfate [2.0% Zn(II); 0.31 mmol/gm particle], 15% NH4Cl, 30% Na2SO4, 50% carbon core). Female 7 wk old BALB/cJ mice were sensitized i.p. with ovalbumin (OVA) in aluminum hydroxide adjuvant or were administered adjuvant only; all mice were challenged with OVA aerosol 14-17 d later. One hour after challenge mice were intratracheally instilled with saline, C, or CZn in saline vehicle (0.5, 2, 5 mg/kg; ~10, 40, 100 mg) and responses were examined 4 hr and 1, 3, and 8 d later. Responsiveness to methacholine (Mch) aerosol (4-32 mg/ml) did not change at any time after exposure in non-sensitized mice exposed to saline or particles. In OVA-allergic saline-exposed mice, responsiveness to 16 mg/ml Mch increased 84% from 4 hr to 8 d after exposure (P < 0.05). Eight days after exposure, both C and CZn particles increased Mch responsiveness to similar degrees vs. saline in OVA-allergic mice (average increase vs. saline at 16 mg/ml Mch: 10 mg: 9%, P > 0.05; 40 mg: 37%, P < 0.05; 100 mg: 53%, P < 0.05). Numbers of bronchoalveolar lavage macrophages, eosinophils, and lymphocytes were increased 8 d after exposure in C- but not CZn-exposed OVA-allergic mice compared to saline-exposed allergic mice. These results show that synthetic carbon-based particles increase airway responsiveness to Mch and lung inflammation in OVA-allergic mice, but addition of zinc to the particles does not significantly enhance these responses. (This abstract does not reflect EPA policy).