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Response of mouse lung to crocidolite asbestos. 2. Pulmonary fibrosis after long fibres
Author(s) -
Adamson Ian Y. R.,
Bowden Drummond H.
Publication year - 1987
Publication title -
the journal of pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.964
H-Index - 184
eISSN - 1096-9896
pISSN - 0022-3417
DOI - 10.1002/path.1711520207
Subject(s) - asbestos , pulmonary fibrosis , lung , asbestosis , medicine , fibrosis , lung fibrosis , pathology , materials science , metallurgy
To determine the cellular and fibrogenic responses of the lung to long asbestos fibres, mice were instilled intratracheally with 0.1 mg of a sample of long crocidolite fibres. Animals were killed at intervals to 20 weeks with 3 H thymidine injected one h before death. Following bronchoalveolar lavage, an increase in polymorph neutrophils (PMN) and alveolar macrophages (AM) was found during the first week, accompanied by elevated glucosaminidase and alveolar protein levels. Although the PMN number dropped, some were always recovered by lavage to 20 weeks. Early multifocal necrosis of bronchiolar epithelium was followed by a large increase in labelling of epithelial cells and underlying fibroblasts. Epithelial overgrowth of luminal long fibres and inflammatory exudates was followed by giant cell and granuloma formation in the interstitium. After four weeks collagen levels were significantly increased and fibrosis was seen in these peribronchiolar locations. A few small fibres were observed in AM but no evidence of fibrosis was seen in alveolar walls. These findings suggest that injury to bronchial and bronchiolar epithelium allows long fibres to reach the interstitium where subsequent macrophage‐fibroblast interactions result in a severe fibrotic reaction that resembles the bronchiolar component of human asbestosis.