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Production of hypersensitivity pneumonitis (HP) in mice by inhalation of spores of Micropolyspora faeni.

Kaliszewski-SD; Thorne-PS; Bleuer-SA
Toxicologist 1992 Feb; 12(1):223
Farmers are exposed daily to an airborne mixture of respiratory irritants, microbial toxins, nuisance dust and a multitude of aeroallergens derived from plants, animals, arthropods, and microbes. Farmer's Lung disease (FLD) is a type of HP characterized by granulomatous interstitial lesions and lymphocytosis. In the midwest, FLD is nearly always linked to exposure to M. faeni (Faeni rectivirgula) , found in "moldy" hay. A murine model was developed using inhalation exposure only, to allow study of the immunologic processes accompanying FLD. M. faeni was cultured at 50 degrees C, then washed, concentrated, and homogenized. Aerosols of this preparation were generated into exposure chambers using a PITT#1 nebulizer, yielding an aerosol with a mass median diameter of 1.2 micro (Sigma(g)=3.25) and a mean count diameter of 0.90 micro. At the highest dose, the M. faeni exposure system produced concentrations of 5.2 +/- 1.5 mg/m3 and 1.7 x 10(9) spores/m3. Viable counts exceeded our detection limit: 1 x 10(7) CFU/m3. Lower exposure levels were obtained by dilution. Groups of 10 mice inhaled M. faeni aerosols for 30 min each exposure either once each wk for 4 or 8 wk, 5 day/wk for 1 or 2 wk, 5 days/wk for 2 wk plus a Day 16 challenge, or were sham exposed. Histopathological examination of lung sections demonstrated marked perivascular and peribronchiolar histiocytosis, localized acute inflammatory cells, fibrosis, and giant cells in granulomatous lesions in mice from several exposure protocols but not in any of the sham exposed mice. This study demonstrates that histopathology characteristic of FLD can be induced using an adjuvantfree inhalation model.
Animal-studies; Animals; Inhalation-studies; Inhalants; Airborne-dusts; Airborne-particles; Lung-disease; Lung-function; Lung-irritants; Lung-disease; Aerosol-particles; Aerosols; Exposure-assessment; Exposure-levels; Exposure-limits; Exposure-methods; Cell-function; Fibrosis; Respiratory-system-disorders; Pulmonary-system-disorders
Publication Date
Document Type
Funding Amount
Funding Type
Cooperative Agreement
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Issue of Publication
Source Name
The Toxicologist. Society of Toxicology 31st Annual Meeting, February 23-27,1992, Seattle, Washingtion
Performing Organization
University of Iowa, Iowa City, Iowa
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division