Fibrinolytic Activity in Thrombosed Veins

Abstract

Thrombosis of the femoral vein in rats was produced by the injection of thrombin, serum, or sodium morrhuate into ligated venous segments. The histologic effects were followed during resolution or organization of the thrombus and were correlated with the appearance and localization of fibrinolytic activity as assayed histochemically. Lysis of the venous thrombus began immediately when thrombin or serum had been used. Sites of thrombolysis were related to the presence of endothelial cells of venous origin and containing plasminogen activator. Sodium morrhuate destroyed the fibrinolytically active endothelial cells thus delaying thrombolysis. Recanalization was associated with the presence locally of active endothelial cells, originating presumably in the adjacent normal venous endothelium. These results support previous observations on the vascular origin of the plasminogen activator. They elucidate the role played by the fibrinolytically active endothelium in the resolution of venous thrombi. They also confirm and extend previous observations on the role of fibrinolytic activity in tissue repair.