From the Institute of Biochemistry and Biophysics, University of Tehran, Iran
Abstract: (4027 Views)
The sequestration of rat leukocytes and bone marrow cells by the lung
vasculature was studied using an isolated perfused rat lung preparation. The
passage of latex particles of 7.6 µm in diameter and non-hematopoietic cells
through the lung blood vessels was also studied. Leukocytes and bone
marrow cells were reversibly sequestered from circulation, whereas, latex
particles and non-hematopoietic cells were removed irreversibly. Continuous
circulation of leukocytes or bone marrow cells results in a steady state
at which circulating cells and the lung reach some kind of equilibrium
wi th no net cell removal by the lung. Further cell removal or release can occur
by changing the circulating cell concentration. Removal of Ca++ and Mg++
from circulating medium decreased the sequestration of leukocytes by the
lung. Complement activation is not involved in this process, since whole
blood as well as serum free suspension of leukocytes, bone marrow cells or
peritoneal cavity neutrophils showed similar patterns of sequestration. The
results indicate that cell sequestration by the isolated perfused lung is a
physiological process which can be considered as a suitable model of the
in-vivo sequestration of blood leukocytes by the vascular system of the body.
The pattern and the rate of sequestration depends on the cell type, cell
concentration in circulation, and chemical factors in circulating medium.
The results provide new information about the mechanisms which might be
responsible for the sequestration of leukocytes by the lung vasculature in the
absence of complement activation