Alveolar macrophages have a dual role in a rat model for trimellitic anhydride-induced occupational asthma.
Occupational exposure to low molecular weight chemicals, like trimellitic anhydride (TMA), can result in occupational asthma. Alveolar macrophages (AMs) are among the first cells to encounter inhaled compounds. These cells can produce many different mediators that have a putative role in asthma. In this study, we examined the role of AMs in lung function and airway inflammation of rats exposed to TMA. Female Brown Norway rats were sensitized by dermal application of TMA or received vehicle alone on days 0 and 7. One day before challenge, rats received intratracheally either empty or clodronate-containing liposomes to deplete the lungs of AMs. On day 21, all rats were challenged by inhalation of TMA in air. Lung function parameters were measured before, during, within 1 h after, and 24 h after challenge. IgE levels and parameters of inflammation and tissue damage were assessed 24 h after challenge. Sensitization with TMA led to decreased lung function parameters during and within 1 h after challenge as compared to non-sensitized rats. AM depletion alleviated the TMA-induced drop in lung function parameters and induced a faster recovery compared to sham-depleted TMA-sensitized rats. It also decreased the levels of serum IgE 24 h after challenge, but did not affect the sensitization-dependent increase in lung lavage fluid IL-6 and tissue TNF-alpha levels. In contrast, AM depletion augmented the TMA-induced tissue damage and inflammation 24 h after challenge. AMs seem to have a dual role in this model for TMA-induced occupational asthma since they potentiate the immediate TMA-induced decrease in lung function but tended to dampen the TMA-induced inflammatory reaction 24 h later.
Valstar
Dingena L
DL
Department of Pharmacology and Pathophysiology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Sorbonnelaan 16, 3584 CA, Utrecht, The Netherlands.
Schijf
Marcel A
MA
Nijkamp
Frans P
FP
Storm
Gert
G
Arts
Josje H E
JH
Kuper
C Frieke
CF
Bloksma
Nanne
N
Henricks
Paul A J
PA
D000485:Allergens; D000704:Analysis of Variance; D000818:Animals; D001249:Asthma / Q000097:blood / Q000139:chemically induced / Q000276:immunology*; D016207:Cytokines / Q000032:analysis; D004195:Disease Models, Animal; D005260:Female; D007073:Immunoglobulin E / Q000097:blood; D008168:Lung / Q000276:immunology; D016676:Macrophages, Alveolar / Q000276:immunology*; D009784:Occupational Diseases / Q000097:blood / Q000139:chemically induced / Q000276:immunology*; D010796:Phthalic Anhydrides; D051381:Rats; D011914:Rats, Inbred BN; D012129:Respiratory Function Tests; D018709:Statistics, Nonparametric
D000485:Allergens; D016207:Cytokines; D010796:Phthalic Anhydrides; D007073:Immunoglobulin E; C015559:trimellitic anhydride