Morphogenesis of chronic lung lesions under the influence of proteolytic enzymes

Abstract

Acute and chronic pathological processes induced in murine lungs by influenza virus or intranasal administration of proteolytic enzymes chymotrypsin and proteinase K were compared. Histologic and electron microscopic analysis showed that a number of characteristics of these two processes were similar. These characteristics included serosanguineous lung edema on days 1-5 postinfection, infiltration of lung tissue with cell elements, metaplasia of bronchial epithelium, and presence of mycoplasma in chronic pneumonia foci. These parameters persisted during 150 days of the experiment without regression. The results suggest the key role of primary cell destruction and proteolytic activity enhancement in the development of chronic influenza-induced pneumonia.