Objective To study the expression and role of plasminogen system in the process of restenosis. Methods We established a double-injury model of atherosclerotic restenosis in rabbit iliac artery mimicking human arterial restenosis. The time course of tissue plaminogen activator (tPA), urokinase plasminogen activator (uPA), urokinase plasminogen activator receptor (uPAR) and plasminogen activator inhibitor-1 (PAI-1) was investigated by immunohistochemistry. The mRNA expression of uPA and uPAR were detected after vascular procedures by in situ hybridization. Results In uninjured arteries, the weak expression of tPA and PAI-1 was detected in intimal and endothelial cells. The expression of tPA, uPA, uPAR and PAI-1 was significantly induced after double-injury, but after double-injury 14d, the expression of tPA restore to preinjury levels. The expression of uPA and uPAR in intimal was higher than that of media and maintain high levels in intimal within 42d and 56d. Conclusion Whereas t-PA is primarily involved in clot dissolution and play a limited role in the process of restenosis, in plasminogen system, uPA and uPAR play a prominent role in the process of restenosis.
