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 r ates can be enhanced by periodic tissue compression or venous pressure elevation, but little is known to what degree enhancement of lymph fl ow affects material transport. The objective was to examine the uptake of plasma proteins, a colloidal perflubron emulsion (LA-11063, mean p article diameter = 0.34 mu m) and leukocytes into lymphatics. Prenodal collecting lymphatics in the lower hindlimb of rabbits were cannulate d with and without foot massage and after elevation of venous pressure (40 mmHg). The average lymph flow rates were elevated similar to 22-f old by the skin massage but only about threefold by venous pressure el evation. Lymph-to-plasma protein concentration ratio remained unchange d by the massage but decreased significantly after venous pressure ele vation, 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. Mas sage is more effective to enhance material transport out of the inters titium into the initial lymphatics.