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Response of mouse lung to crocidolite asbestos. 1. Minimal fibrotic reaction to short 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.1711520206
Subject(s) - asbestos , lung , pathology , asbestosis , fibrosis , macrophage , pulmonary fibrosis , alveolar macrophage , bronchoalveolar lavage , chemistry , medicine , in vitro , biochemistry , materials science , metallurgy
To determine the relationship between the development of pulmonary fibrosis and the size of deposited asbestos, we prepared a pure sample of short crocidolite fibres and instilled 0.5 mg of 0.1 mg to the lungs of mice. Animals were killed up to 20 weeks later with 3 H thymidine injected 1 h before death. By bronchoalveolar lavage, there was a rapid transient increase in polymorph neutrophils (PMN) and in glucosaminidase levels; alveolar macrophage (AM) numbers were elevated in the 0.5 mg group for eight weeks. Most fibres were phagocytized by AM, many of which were heavily laden and cleared from the lung over the 20 week period. Some fibres were seen in type 1 epithelial cells, frequently associated with cell injury. From cell kinetic studies, a very brief proliferative response was seen in bronchiolar epithelial and Type 2 alveolar epithelial cells. A greater response was seen in interstitial fibroblasts which showed increased labelling up to two weeks after 0.5 mg asbestos. However no granulomas were seen and very little fibrosis was found by morphology or by biochemistry at any time after 0.5 mg; no fibrosis was seen after instilling 0.1 mg. The results show that a high dose of exclusively short asbestos fibres produces minimal lung injury and fibrosis in spite of long standing macrophage‐fibre interaction in the alveoli.