Emphysema associated with intravascular leukocyte sequestration. Comparison with papain-induced emphysema.

The pulmonary effects of endotoxin-induced, repetitive, intravascular leukocyte sequestration were studied in dogs and were compared to the effects of intratracheal papain. Lung specimens from 7 animals receiving 20 to 23 weekly injections were histologically and physiologically similar to those from 10 control animals. Dogs receiving 50 injections of endotoxin during 17 wk developed histologic evidence of emphysema as seen on whole lung sections, a significant increase in mean linear intercept, and loss of elasticity at high lung volumes. The group of animals given intratracheal papain also developed histologic evidence of emphysema, with increased mean linear intercepts and loss of lung elasticity. However, the effects on lung elasticity were much greater in the papain group. Endotoxin-induced, repetitive leukocyte sequestration in the lungs results in mild emphysema; however, similar changes in alveolar size appear to cause less effect on the pressure-volume loop than does papain-induced emphysema.