Experimental Study on Fibrogenic Effect of Fur Dust on Rat Lung

ABSTRACT

Objective: The fibrogenicity of fur dust was studied in rat lung tissues. Methods: Intratracheal instillation of fur dust, morphologic examination of lungs and analysis of collagen content were performed in Wistar rats. Results: Morphologic examination revealed that the earliest changes consisted of alveolar edema, increased numbers of intraalveolar macrophages, and marked thickening of interalveolar septa with mixed cellular infiltrate. After sixth months, there was moderate thickening of the alveolar walls and the peribronchioli. After 12 months, interstitial positive fibrosis of the alveolar wall and the peribronchioli were weakly seen. In the carding dust group (silica content 17.6%), interstitial nodules were observed composed of fibroblasts, reticular fibers, and collagen fibers. Electron microscopic examination also showed that alveolar walls became thickened and collagen fiber bundles were seen around bronchioles and small vessels in the carding groups after 12 months. At all stages of analysis, the collagen content in lungs of the fur dust groups was significantly higher than that of the control group. Conclusions: Our study suggested that fur dust might induce weak interstitial fibrosis in the lung.