Interstitial fluid, plasma protein, colloid, and leukocyte uptake into initial lymphatics

Lymphatics serve to remove from the interstitium a range of materials, including plasma proteins, colloid materials, and cells. Lymph flow rates can be enhanced by periodic tissue compression or venous pressure elevation, but little is known to what degree enhancement of lymph flow affects material transport. The objective was to examine the uptake of plasma proteins, a colloidal perflubron emulsion (LA-11063, mean particle diameter = 0.34 micron), and leukocytes into lymphatics. Prenodal collecting lymphatics in the lower hindlimb of rabbits were cannulated with and without foot massage and after elevation of venous pressure (40 mmHg). The average lymph flow rates were elevated approximately 22-fold by the skin massage but only about threefold by venous pressure elevation. Lymph-to-plasma protein concentration ratio remained unchanged by the massage but decreased significantly after venous pressure elevation. Lymph colloid concentration and leukocyte counts were elevated on average 47 and 8.5 times, respectively, by foot massage, but both decreased after venous pressure elevation. These results suggest that skin movement by massage and elevation of the venous pressure lead to opposite lymph transport kinetics of protein, colloids, and cells. Massage is more effective to enhance material transport out of the interstitium into the initial lymphatics.