Effect of platelet inhibition on experimental venous thrombosis in the rabbit

An experimental model, based on a combination of endothelial damage and flow reduction, was used to induce thrombosis of the jugular vein in rabbits. The influence of ibuprofen, a cyclooxygenase inhibitor, was compared with that of dextran 70, which influences platelets, thrombus structure and flow. Albumin was used as a control of the volume-expanding effect of dextran. Ibuprofen was administered intravenously during the induction of thrombosis, and dextran and albumin were given 3 hours before the surgical procedure. Control rabbits received only Ringer's lactate. Dextran, but neither ibuprofen nor albumin, significantly reduced the incidence of thrombosis, though thrombus weight was not influenced. The data indicated that the effect of dextran in this model probably is primarily exerted via alteration of thrombus structure, and not by altered platelet function or hemodilution. The role of platelets in the initial development of thrombosis in this model thus may be questioned.