The influence of dust originated in different coal mines on pneumoconiotic changes in white rats.

In experiments on white rats, three different types of dust of equal dispersion, coming from coal mines, were examined. The dusts exhibited different content of free silica and certain metals, such as: nickel, chromium and vanadium. The animals intratracheally administered with 50 mg of the mentioned dusts had hydroxyproline determined. After six months of experiment, histopathological examination of lungs was carried out. It was found that different SiO2 content (5 and 11%) with the same content of trace metals and different content of trace metals with the same SiO2 content (5%) does not affect hydroxyproline content in lungs. A significant increase in hydroxyproline level in rats' lungs was found in a group that obtained dust of the highest SiO2 content (11%) with more trace metals. Findings of histopathological examinations confirmed the data obtained from hydroxyproline levels measurements. It seems that compounds of certain metals, such as: nickel, chromium, vanadium, at a specific SiO2 level in the dust may increase its fibrogenic properties in lungs.