Journal of Applied Physiology, Vol 48, Issue 3 414-420, Copyright © 1980 by American Physiological Society
Effect of platelet depletion on lung vascular permeability after microemboli in sheep
A. S. Binder, W. Kageler, A. Perel, M. R. Flick and N. C. Staub
To test whether platelets are necessary for the increased vascular
permeability associated with microemboli, we used 16 anesthetized sheep in
which we measured lung lymph flow, pulmonary arterial and left atrial
pressures, thermodilution cardiac output, and lymph/plasma protein
concentration. Injecting glass bead microemboli (200 micrometers diam)
until pulmonary vascular resistance increased to three times base-line
values caused lung lymph flow to increase at nearly constant
lymph-to-plasma protein concentration ratio that is characteristic of
increased microvascular permeability. Antiplatelet serum alone caused
transient increases in pulmonary vascular resitance and lung lymph flow,
but produced no change in steady-state lung fluid balance. After depleting
platelets by greater than 97%, tripling pulmonary vascular resistance with
emboli resulted in increases in lung lymph and protein flow comparable to
that seen in untreated sheep. We injected twice the amount of beads in
thrombocytopenic sheep compared to untreated sheep. We conclude that,
although platelets do augment the pulmonary hypertension after emboli, they
are not essential for the microemboli vascular injury.
