[Expression of tissue-type plasminogen activator (t-PA) in smooth muscle cells of injured iliac arteries in rabbits].

To investigate the mechanism of atherogenesis and development of restenosis following angioplasty, the expression of t-PA in SMC at different intervals after the arterial injury was measured by morphological analysis, plasmin generation assay and in situ hybridization. t-PA activity of the iliac arteries was noticed to be significantly increased on the 4th day after injury, signalling the commencement of SMC migration from the media to intima, t-PA activity then decreased to approximately the normal level on the 7th day. Results from in situ hybridization also showed that the expression of t-PA mRNA in the intima and media increased significantly on the 4th day after the arterial injury, by the 7th day, t-PA mRNA was detected only in SMC located adjacent to the internal elastic lamina. These results suggest that t-PA might play an important role in SMC proliferation and migration following arterial injury.