The effects of puerarin on platelet activation and expression of angiotensin II AT_1 receptor mRNA after vascular balloon injury in rats

Objective To investigate the process of neointimal formation, the level of platelet activation, the expression of angiotensinⅡ AT_1 receptor mRNA and the effects of puerarin on them after vascular balloon injury in rats. Methods Make models of aortic endothelial denudation of rats by balloon catheter. Rats were randomly allocated into three groups. Group 1 ( n =24) served as controls.Group 2 ( n =24) were given vascular balloon injury. Group 3 ( n =24) were given puerarin (50 mg·kg -1 ·d -1 ) into peritoneum from 1 day before injury to 28 days after injury. The level of AT_1 receptor mRNA , the number of platelet GMP-140 and the process of intimal thickening were investigated at day 3,7,14 and 28 after injury by RT-PCR technique, radioimmunological method and histological method. Results (1) The expression of AT_1 receptor mRNA increased significantly at day 3 after balloon injury and remained high at day 14 . (2)The number of platelet GMP-140 were higher obviously at day 3 and began to decrease at day 7 after injury. (3) The migration and proliferation of vascular smooth muscle cells(VSMC) had existed at day 3 after balloon injury. The thickening of intima had begun at day 7 after injury, and they were more significant at day 14 . The proliferation of VSMC decreased at day 28 , but extracellular matrix increased and the intimal thickening continued.(4) When given puerarin, the number of platelet GMP-140 and the migration of VSMC reduced, but the level of AT_1R mRNA and the intimal thickening had no significant variation. Conclusion The expression of AT_1R mRNA and the number of platelet GMP-140 increased in the process of intimal thickening after balloon injury. Puerarin could inhibit the activation of platelet, but had no obvious effect on the expression of AT_1R mRNA and intimal thickening.