ABSTRACT
<p><b>OBJECTIVE</b>To explore the characters of lung injury induced by tin dusts and to provide the diagnosis evidence of tin pneumoconiosis.</p><p><b>METHODS</b>Forty SD rats were randomly divided into four groups: the group exposed to tin dusts from smelting workshop, the group exposed to tin dusts from tin refining workshop, the positive control group exposed to standard quartz dusts and the negative control group exposed to saline. The pathological changes of rat lungs were observed dynamically.</p><p><b>RESULTS</b>In rats exposed to tin dusts, on the 30th day after exposure to tin dusts, the scattered hoar tip size of the spots in surface and section of the lungs were observed, the scattered focal granulomatous inflammation around the small bronchi and dust particles in lung tissue were observed under microscope; on the 90th day after exposure to tin dusts, the granulomatous inflammation increase, the fibroblasts proliferation, collagen fibers formation and positive VG staining were found. There were significant differences, as compared with positive or negative controls (P < 0.05). These pathological changes were basically the characters of specific pathological changes in early tin pneumoconiosis.</p><p><b>CONCLUSION</b>Non-ferrous metal tin dusts can induce the specific lung injury (granuloma formation) in lung tissue of rats exposed to tin dusts, which fulfilled the diagnostic criteria of specific pathological changes in early tin pneumoconiosis.</p>