Relationships between Morphological Changes and Content of Silica and Hydroxyproline in Bronchi and Lungs of Coal Miners

Abstract

The authors examined the lungs of 29 coal miners with various grades of pneumoconiosis for histological changes and for the content of silica, hydroxyproline and hexosamine. The changes found in lungs were classified into the following groups: interstitial focal pneumoconiosis (simple pneumoconiosis), progressive massive fibrosis and coniotuberculosis. The changes found in bronchi occurred in foci and the most serious of them were noticed in the neighborhood of peribronchial granulomas that adhered to or proliferated in bronchial walls. The content of silica in progressive massive fibrosis lesions was three times higher than that in the pulmonary tissue with simple pneumoconiosis. The walls of bronchi of the 1st, 2nd and 3rd order contained comparatively very little silica—only one third of the content found in the pulmonary tissue with simple pneumoconiosis. The content of hydroxyproline in progressive massive fibrosis lesions was equal to that in the pulmonary tissue with simple pneumoconiosis despite the fact that dust was accumulated in the lesions. The content of hydroxyproline in the bronchi of coal miners with pneumoconiosis was equal to that found in control subjects of the same age; it decreased from the bronchi of the 1st order to the bronchi of the 3rd order but was always higher there than in pulmonary tissue.