[Pathological study of bronchio-alveolitis induced by xinkang short-fiber chrysotile asbestos in rats].
Eighty-four rats were exposed intratracheally to 25 mg of locally produced Xinkang short-fiber chrysotile asbestos (98% of the fibers are less than 5 microns in length). In 1 to 3 d after instillation, the pathological changes in rat lungs demonstrated that the affection was mainly acute bronchio-alveolitis characterized by acute inflammatory exudation and injuries of the small airways and alveolar structural units. The four main manifestations of alveolitis induced by the chrysotile asbestos were of the neutrophilic, serous, alveolar macrophages and granulomatous varieties. Three types of pulmonary fibrosis developed gradually from 7 to 90 d following the exposure to the asbestos, i.e. the intraluminal, murally incorporated, and interstitial fibrosis. Findings showed the complete process from the acute inflammatory exudation and the damage to lung tissue, with the following repair and proliferation of injuried lung tissue and organization of exudate, to the final fibrosis and destruction of the lung. The results suggested that the persistent and irreversible damage to the epithelial cells of respiratory bronchioles and pneumocytes, and denudation and destruction of the basement membrane played an important role in the development of pulmonary fibrosis by forming a channel for the inflammatory exudates and fibroblasts migrating into the bronchioalveolar spaces. Therefore, the experimental results have proved that Xinkang chrysotile asbestos fibers less than 5 microns in length certainly have a fibrogenic effect.
Zeng
L
L
Zheng
Z R
ZR
Li
H Y
HY
Tan
J S
JS
D000818:Animals; D001194:Asbestos / Q000009:adverse effects*; D008168:Lung / Q000648:ultrastructure*; D008297:Male; D011658:Pulmonary Fibrosis / Q000209:etiology* / Q000473:pathology; D051381:Rats; D011919:Rats, Inbred Strains
D001194:Asbestos