An experimental study of lung lesions caused by extracellular enzyme of streptomyces thermohygroscopicus

Abstract

Rabbits and rats were infected intratracheally with extracellular enzyme of Streptomyces thermohygroscopicus (H_9-4) by only one exposure, and lesions of the lung developed including 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. Immunofluorescent histochemistry examination revealed exudation of plasma fibronectin which might play an important role during the process of lesion repairing in lung. The experiment also confirmed that extracellular enzyme of Streptomyces thermohygroscopicus might directly damage the lung tissue. These experimental data may serve as valuable reference for studying the etiology and pathogenesis of farmer’s lung disease.

Keywords

farmer’s lung / Streptomyces thermohygroscopicus / extracellular enzyme / fibronectin

References

[1] ReyesCN, et al. . The pulmonary pathology of farmer’s lung disease. Chest, 1982, 81: 142-6

[2] HarrisJO, et al. . Experimental granulomatous pneumonitis: bronchopulmonary response to Micropolyspora faeni in the rabbit. Chest, 1976, 69: 287-8

[3] NicoletJ, et al. . Experimental farmer’s lung: Immunological response in the rabbit to protein fractions of Micropolyspora faeni. Z Immuno-Forsch, 1979, 155: 399-410

[4] PepysJ, et al. . Farmer’s lung: Thermophilic actinomycetes as a source of “famer’s lung hay” antigen. Lancet, 1963, 2: 607-11

[5] GuoJ, CheDY. Experimental farmer’s lungs. J Tongji Med Univ, 1986, 6: 191-7

[6] SchorlemmerHU, et al. . Macrophage responses to mouldy hay dust, Micropolyspora faeni, and zymosan, activators of complement by the alternative pathway. Clin Exp Immunol, 1977, 27: 198-207

[7] SchällibaumM, et al. . Histopathological and immunohistological changes in the rabbit lung after experimental exposure to a purified enzyme of Micropolyspora faeni. Clin Exp Immunol, 1977, 28: 535-541

[8] HynesRO. Fibronectins. Sci Am, 1986, 254: 32-42