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Alveolar macrophages have a dual role in a rat model for trimellitic anhydride-induced occupational asthma

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Author: Valstar, D.L. · Schijf, M.A. · Nijkamp, F.P. · Storm, G. · Arts, J.H.E. · Kuper, C.F. · Bloksma, N. · Henricks, P.A.J.
Institution: TNO Kwaliteit van Leven
Source:Toxicology and Applied Pharmacology, 1, 211, 20-29
Identifier: 239132
doi: doi:10.1016/j.taap.2005.05.012
Keywords: Health · Toxicology and Applied Pharmacology · Airway inflammation · Alveolar macrophages · Early asthmatic response · Occupational asthma · Trimellitic anhydride · clodronic acid · immunoglobulin E · interleukin 6 · liposome · trimellitic anhydride · tumor necrosis factor alpha · animal cell · animal experiment · animal model · animal tissue · article · body weight · cell function · controlled study · disease severity · female · immunoglobulin blood level · lung alveolus macrophage · lung function · lung injury · lung lavage · lymphocyte depletion · nonhuman · occupational asthma · organ weight · rat · respiratory tract inflammation · Allergens · Analysis of Variance · Animals · Asthma · Cytokines · Disease Models, Animal · Female · Immunoglobulin E · Lung · Macrophages, Alveolar · Occupational Diseases · Phthalic Anhydrides · Rats · Rats, Inbred BN · Respiratory Function Tests · Statistics, Nonparametric · Animalia · Rattus norvegicus


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-α 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. © 2005 Elsevier Inc. All rights reserved.