[Study of experimental lung lesions caused by extracellular enzyme of Streptomyces thermohygroscopicus].

Rabbits and rats were infected intratracheally with extracellular enzyme of streptomyces thermohygroscopicus (H9-4) for only one exposure and lesions of lung developed which included mononuclear macrophage infiltration as well as bronchitis and vasculitis. The obvious damages in type I pneumocytes, endothelial cells of capillaries and arterioles in the lung were observed by electron microscopy. Immunofluorecent histochemistry examination revealed exudation of plasma fibronectin which might be important to play certein role during the process of wound repairing in lung. The experiment also confirmed that extracellular enzyme of streptomyces thermohygroscopicus might directly damage the lung tissue, and these experimental data may serve valuable reference for studying the etiology and pathogenesis of farmer's lung diseases.