ABSTRACT
Lobar intrabronchial instillation of cadmium chloride (200 micrograms/ml) in saline causes a reproducible acute pulmonary inflammation in dogs. The influx of inflammatory neutrophils from the circulation into the alveolar spaces reaches a maximum approximately 16 hours after the cadmium chloride treatment in the treated lobe, while the controlateral lung appears normal. Morphometric quantitation of peroxidase-positive (azurophilic) granules in the inflammatory neutrophils shows a 74% loss of these granules, with little or no loss of the peroxidase-negative (specific) granules. These data are in good agreement with the measured loss of intracellular elastase, an enzyme known to be localized in the azurophilic granules. The results suggest that degranulation of azurophilic granules may occur selectively during this chemically induced acute inflammation.
Subject(s)
Cadmium/pharmacology , Pneumonia/chemically induced , Animals , Cadmium Chloride , Cytoplasmic Granules/drug effects , Dogs , Female , Histocytochemistry , Male , Microscopy, Electron , Neutrophils/drug effects , Neutrophils/ultrastructure , Pancreatic Elastase/metabolismABSTRACT
The appearance of neutrophils in the alveoli of the lung is a common result of pulmonary infection, although the route of neutrophil migration across the alveolar wall has not been demonstrated in normal animals. Recently, however, several methods of stimulating the influx of neutrophils into alveoli have been developed. In the present study, the lung wash model was used to attract large numbers of neutrophils into the airways in order to identify the site of influx of alveolar neutrophils. The combined use of scanning and transmission electron microscopy has made it possible to visualize the migration of neutrophils from the capillaries, through the interstitial spaces, and through the epithelium at the junctions between Type I and Type II cells.
