Journal of Applied Physiology, Vol 73, Issue 1 166-172, Copyright © 1992 by American Physiological Society
Effects of cold on vascular permeability and edema formation in the isolated cat limb
M. B. Wolf, L. P. Porter, D. R. Scott 2nd and J. X. Zhang
Department of Physiology, School of Medicine, University of South Carolina, Columbia 29208.
We investigated the effects of cold temperatures on microvascular protein
permeability in the isolated constant-flow perfused cat hindlimb. The
perfusates were 20% cat plasma-80% albumin-electrolyte solution
(low-viscosity perfusate, approximately 1 cP) or whole blood
(high-viscosity perfusate, approximately 4 cP). The time at low temperature
(less than 10 degrees C) was less than 3 h (short term) or greater than 5 h
(long term). Decreases in the solvent drag reflection coefficient (sigma f)
indicated increases in permeability. The sigma f's were determined with the
integral-mass balance method from measurement of changes in protein
concentration and hematocrit induced by fluid filtration into the tissues.
Short-term cold exposure did not increase permeability with either a low-
or a high-viscosity perfusate, whereas long-term exposure with limb
temperatures of approximately 5 degrees C significantly increased
permeability when the perfusate was whole blood. In addition, we verified
our previous prediction that flow had to be reduced to 6-8 ml.min-1.100 g-1
to avoid the hydrostatic edema caused by short-term perfusion with whole
blood at approximately 5 degrees C. Also, we found that at approximately 3
degrees C histamine's permeability-increasing effect was totally abolished,
whereas at approximately 20 degrees C this effect was partially inhibited.
Hence, constant-flow perfusion at low temperature with whole blood can
cause edema by a pressure-dependent mechanism, whereas long-term perfusion
with this perfusate at low temperatures can cause a permeability increase
that further compounds edema formation. Histamine is not responsible for
this permeability increase.
