Kinetics of reversible-sequestration of leukocytes by the isolated perfused rat lung

Abstract

The kinetics and morphology of seauestration and margination of rat leukocytes were studied using an isolated perfused and ventilated rat lunq preparation. Whole rat blood, bone marrow suspension, or suspensions of peritoneal neutrophils, referred to as 1eukocyte suspensions, were used to perfuse the isolated rat lung either in the single-pass or continuous-circulation mode. Samples were collected from the lung affluent and effluent suspensions at various intervals and their leukocyte concentrations were determined. The lung was also oerfused with latex particle suspensions and the passage of particles thrOIJg~ the lung capillaries was studied. Lungs prefused with leukocvte or latex particle suspensions were fixed by the tracheal infusion techniaue, ethanol-cryofractured, and processed for scanning electron microscopy.When a leukocyte suspension was perfused through the lung in the single-pass mode, the rate of seauestration decreased as more cells were perfused. In contrast, latex particles of a size comparable to that of leukocytes were totally stopped by the lung. With the scanning electron microscope, latex particles were seen plugging the capillaries and small arterioles. When the leukocyte suspension was recirculated through the lung, cells were rapidly removed from circulation until a st~ady state was reached, after which no net removal of cells by the * Lawrence Berkeley Laboratory, University of California, Berkeley, CA 94720.