抄録
Recently, asbestos fiber has been used in various ways in our industrialized society, and much attention has been paid to the various lung disease conditions which are induced by the inhalation of asbestos fibers.
The author has been made an investigation on the fibrosis which is induced by asbestos fiber inhalation. In this experiment, 10mg of chrysotile was suspended in normal saline at the concentration of 0.1mg/ml.
It was then injected to the rats by intubation. In a chronological study of the fibrosis, the patho-logical process was studied by the conventional light and electron microscopes, as well as by histoche-mical methodology involving the PAM stain and enzyme histochemical techniques.
As the results, several interesting findings were noted. Firstly, in the early stages, 1 week after inoculation of the chrysotile fibers, an acute foreign body granuloma with inflammatory response, marked interstitial edema, hemorrhage and destruction of the lung structure were noted.
In due time, the proliferation of the reticulin and collagen fibers were noted. More than 6 months after the inoculation of the chrysotile, the pathological changes tended to be rather localized, and aggregate of the fibrotic foci were observed in the peripheral region of the airways. However, the interaction among the chrysotile fibers, fibroblasts, type I epithelial cells and mast cells were prominent.
This suggests the presence of the chrysotile may play a very important role in causing this fibrotic process.
In this formative process of pulmonary fibrosis, the disintegration and death of the macrophages which took part in phagocytosis of the chrysotile and the leakage of their hydrolytic enzymes into the tissues and alteration of the physiochemical properties of the chrysotile may be closely related.
