Journal of Applied Physiology, Vol 63, Issue 5 1770-1775, Copyright © 1987 by American Physiological Society
Lung endothelial and epithelial permeability after platelet-activating factor
R. W. Bolin, T. R. Martin and R. K. Albert
Medical Service, Veterans Administration Medical Center, Seattle, Washington.
We investigated whether platelet-activating factor (PAF) increased
epithelial or endothelial permeability in isolated-perfused rabbit lungs.
PAF was either injected into the pulmonary artery or instilled into the
airway of lungs perfused with Tyrode's solution containing 1% bovine serum
albumin. The effect of adding neutrophils or platelets to the perfusate was
also tested. Perfusion was maintained 20-40 min after adding PAF and then a
fluid filtration coefficient (Kf) was determined to assess vascular
permeability. At the end of each experiment, one lung was lavaged, and the
lavagate protein concentration (BALP) was determined. Wet weight-to-dry
weight ratios (W/D) were determined on the other lung. PAF added to the
vascular space increased peak pulmonary arterial pressure (Ppa) from 13.5
+/- 3.1 (mean +/- SE) to 24.2 +/- 3.3 cmH2O (P less than 0.05). The effect
was amplified by platelets [Ppa to 70.8 +/- 8.0 cmH2O (P less than 0.05)]
but not by neutrophils [Ppa to 22.0 +/- 1.4 cmH2O (P less than 0.05)].
Minimal changes in Ppa were observed after instilling PAF into the airway.
The Kf, W/D, and BALP of untreated lungs were not increased by injecting
PAF into the vasculature or into the air space. The effect of PAF on Kf,
W/D, and BALP was unaltered by adding platelets or neutrophils to the
perfusate. PAF increases intravascular pressure (at a constant rate of
perfusion) but does not increase epithelial or endothelial permeability in
isolated-perfused rabbit lungs.
