Low-level subchronic exposure to wood smoke exacerbates inflammatory responses in allergic rats.
Epidemiological studies have implicated wood smoke as a risk factor for exacerbating asthma. However, comparisons of findings in animal models with those in humans are currently not possible, because detailed clinically relevant measurements of pulmonary function are not available in animal studies. Brown Norway rats were immunized with ovalbumin and exposed to either filtered air or wood smoke at 1 mg particulate matter/m(3) for 70 days and challenged with allergen during the last 4 days of exposure. Baseline values for dynamic lung compliance were lower while functional residual capacity was increased in rats exposed to wood smoke compared to rats exposed to filtered air. IFN-gamma levels were reduced and IL-4 levels increased in the bronchoalveolar lavage fluid and blood plasma, inflammatory lesions in the lungs were 21% greater, and airway mucous cells/mm basal lamina were non-significantly increased in rats exposed to wood smoke compared to controls. Collectively, these studies suggest that the pulmonary function was affected in rats by exposure to wood smoke and this decline was associated with only minor increases in inflammation of the lung. Therefore, this animal model may be useful to elucidate the mechanisms of the decline in pulmonary function caused by environmental pollutants when asthmatics are exposed to allergen.
Tesfaigzi
Yohannes
Y
Lovelace Respiratory Research Institute, Albuquerque, NM 87108, USA. ytesfaig@lrri.org
McDonald
Jacob D
JD
Reed
Matthew D
MD
Singh
Shashibhushan P
SP
De Sanctis
George T
GT
Eynott
Paul R
PR
Hahn
Fletcher F
FF
Campen
Matthew J
MJ
Mauderly
Joe L
JL
D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D000397:Air Pollution / Q000009:adverse effects* / Q000032:analysis; D000485:Allergens / Q000494:pharmacology; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology; D019570:Inhalation Exposure; D007371:Interferon-gamma / Q000032:analysis; D015847:Interleukin-4 / Q000032:analysis; D008297:Male; D010047:Ovalbumin / Q000494:pharmacology; D051381:Rats; D011914:Rats, Inbred BN; D012129:Respiratory Function Tests; D012130:Respiratory Hypersensitivity / Q000139:chemically induced* / Q000276:immunology / Q000473:pathology; D020545:Respiratory Mucosa / Q000187:drug effects / Q000473:pathology; D012906:Smoke / Q000009:adverse effects* / Q000032:analysis; D014934:Wood
D000393:Air Pollutants; D000485:Allergens; D012906:Smoke; D015847:Interleukin-4; D007371:Interferon-gamma; D010047:Ovalbumin