Neurtrophil degranulation in cadmium-chloride-induced acute lung inflammation.

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.

A model of decreased functional alpha-1-proteinase inhibitor. Pulmonary pathology of dogs exposed to chloramine T.

The objective of this study was to develop an animal model representative of chronic human alpha-1-proteinase inhibitor deficiency. Eight dogs were treated with a mild oxidizing agent, chloramine T, with varying regimens for 3--27 wk. The capacity of the serum to inhibit both trypsin and elastase was examined and found to respond differently. Although immunologically determined levels of protease inhibitor did not change, the ability of serum to inhibit elastase in an in vitro assay decreased in direct response to chloramine T treatment. The trypsin inhibitory capacity was less affected. Emphysemalike alterations in lung morphology were observable when histologic sections were evaluated both subjectively and objectively by mean linear intercept measurements. The data suggest that this model parallels the emphysema associated with the genetic alpha-1-proteinase inhibitor deficiency in man.

Emphysema induced in vitro and in vivo in dogs by a purified elastase from homologous leukocytes.

The protease hypothesis of emphysema development evolved from systems using intratracheal instillation or aerosols of heterologous enzymes, such as papain or porcine pancreatic elastase, which bear no relation to the animal species treated. Although these enzymes did produce experimental emphysema, their exogenous origin and superphysiological dosages limit their use in definitive model systems. The observation that dog leukocyte homogenates could induce canine emphysema led us to purify the causative agent from canine neutrophils. This report establishes that a single elastolytic enzyme from dog neutrophils is responsible for inducing experimental emphysema in the dog. Two purification methods were employed. The first used solvents of increasing ionic strength in a sequential extraction of acetone powders of purified dog neutrophils. The ability to initiate emphysema-like lesions was tested in every fraction of the purification and was localized in the extract with the highest true elastolytic activity. The second purification involved neutrophil intracytoplasmic organelle fractionation and established that only extracts of the lysosomal granules were capable of emphysema induction. Finally, the enzyme was purified to homogeneity from the granules using affinity chromatography and was shown to be a true elastase. Emphysema development was quantitated using mean linear intercept and was shown to be dependent on elastase concentration. There does not appear to be any other single enzyme in the canine neutrophil capable of inducing experimental emphysema.