AJP - Heart and Circulatory Physiology, Vol 246, Issue 2 180-H188, Copyright © 1984 by American Physiological Society
Depressed reticuloendothelial clearance of platelets in rats after trauma
J. E. Kaplan, D. G. Moon, F. L. Minnear and T. M. Saba
Platelet microembolization may contribute to microcirculatory and organ
damage following trauma and shock. It is hypothesized that posttraumatic
reticuloendothelial depression predisposes to such microembolization by
failure to clear altered platelets from the circulation. The present study
evaluated the short-term (1 h) clearance and organ localization of
radiolabeled homologous damaged platelets in normal rats and in rats
following sublethal Noble-Collip drum trauma. Platelets were collected in
citrated platelet-rich plasma from normal rats and labeled with 51Cr in
citrated saline. Platelets were altered by repeated centrifugation in
protein-free medium. These platelets differed functionally and
morphologically from normal platelets. Disappearance of iv injected damaged
platelets conformed to a two-compartment exponential clearance. Velocity of
clearance in the rapid compartment correlated with hepatic platelet
localization, whereas velocity of clearance in the second compartment
correlated with splenic platelet localization. Clearance rate of the rapid
compartment was depressed at 1 h after trauma and elevated at 24 h. These
changes were associated with a decrease in hepatic platelet localization at
1 h and an increase above normal at 24 h. Splenic platelet localization was
decreased by 3 h following trauma. Pulmonary platelet localization was
increased at all times following trauma. It is concluded that the
posttrauma state is associated with a defect in the reticuloendothelial
system clearance of altered platelets, which may augment embolization of
platelets in the lung.
