球囊损伤大鼠主动脉内皮后血小板活化及凝血酶受体表达的变化

The Altervation of Platelet Activation and Expression of Thrombin Receptor mRNA after Aortic Balloon Injury in Rats

目的探讨经皮冠状动脉腔内成形术后再狭窄的发生机制。方法建立大鼠主动脉内皮球囊损伤模型,分别于术后3天、7天、14天和28天,通过组织学检查、放射免疫法和逆转录—聚合酶链反应技术检测主动脉球囊损伤后内膜增生的情况、血小板表面GMP140数目和凝血酶受体mRNA表达的变化。结果凝血酶受体mRNA在正常血管组织的表达较弱,球囊损伤术后第3天已显著增加,术后第14天达峰值,术后第28天开始下降。GMP140于术后第3天明显升高,术后第7天开始下降。内皮损伤术后第3天已有增殖的血管平滑肌细胞移行至内膜层;术后第7天内膜开始增生;术后第14天血管平滑肌细胞的增殖及内膜增生更为明显;术后第28天血管平滑肌细胞的增殖明显减弱,细胞外基质增加,内膜继续增生。结论血管内皮损伤内膜增生的过程中血小板活化,凝血酶受体mRNA表达增加。

Aim To investigate the process of neointimal formation, level of platelet activation and thrombin receptor mRNA by means of a rat aortic balloon injury model in order to study the mechanism of acute and late restenosis after pereutaneous transluminal coronary angioplasty（PTCA）. Methods Forty eight male Wistar rots were divided into two groups randomly. Group 1 （n=24） served as controls, group 2 （n=24） were given aortic balloon injury by self-made 2F balloon catheters. The process of intimal thickening, number of platelet GMP-140 and level of thrombin receptor mRNA were investigated at day 3, 7, 14 and 28 after balloon injury by histological method, radioimmunological method and reveise transcription polymerase chain reaction （RT-PCR） technique, respectively. Six rats were examined at each group. Results The expression of thrombin receptor mRNA was at a low level in endothelium and smooth muscle cell of normal arteries, but increased significantly at day 3 after balloon injury, reached its peak at day14 and decreased at day 28. The number of platelet GMP-140 was higher at day 3 and began to decrease at day 7 after injury. The migration and proliferation of vascular smooth muscle cell had existed at day 3 after balloon injury. The intimal thickening began at day 7 after injury, and it was more significant at day 14. The proliferation of VSMC decreased at day 28, but extracellular matrix increased and the intimal thickening continued. Cotadusions The expression of TR mRNA and the number of platelet GMP-140 increase in the process of intimal thickening after balloon injury.