Use Inhibites Neointimal Hyperasia Follewing Carotid Artery Lesions Of Rats

Objective: Ultrasound exposure with different frequency ,intensity was investigated to the neointimal proliferation and the mechanism of vascular smooth muscle cells of apoptosis in carotid artery of rats after balloon injury. Optimal therapeutic parameters were chosen for ultrasound to prevent restenosis.Methods: Thirty-five male Wistar rats(350±50g) were randomly divided into seven groups: controlled group(only balloon dilation),built animal models after the carotid artery of rats was denudated by 2 Forgarty catheter; USE therapeutic group: after balloon dilation, USE with frequency of 705KHz, 2.17MHz, 5.48MHz, intensity of 1W/cm2,2W/cm2 was applied locally to the injured blood vessels in the treatment group for 3 minutes. The target of artery vessel were got and applied to the HE staining and elastic fiber staining respectively two weeks after the injury. The medial area (MA),neointimal area(NIA) and neointimal area(NIA)/ medial area(MA) were analyzed by computerized system. Apoptosis were assessed respectively by TUNEL marking method. The percentage of apoptosis byTUNEL marking method was calculated to observe the change of USE to vascular smooth muscle cell.Results: 1.The morphological examination: different degree of intimal hyperplasia was found both in treatment group and controlled group two weeks after balloon dilation. The neointimal area and NIA/MA was differently reduced in the treatment group compared with the controlled group. The reduce of neointimal area and NIA/MA in 705KHz,1W/cm2 group had statistical significance(0.04±0.05vs0.18±0.05,P<0.05;0.25±0.29vs1.33±0.51,P<0.05) compared with the controlled group. But there is no statistical difference between other groups and controlled group (P>0.05).2.TUNEL%: After two weeks, the ratio of positive cells marked by TUNEL in the treatment group was higher than the controlled group. The ultrasound group of 705KHz,1W/cm2 had statistical significance(30.2±3.8%vs18.6±2.4%,P<0.05) compared with the controlled group. But there is no statistical difference between other groups and controlled group (P>0.05). Conclusion: USE with definite intensities significantly inhibited the proliferative activity of intima following carotid artery lesions of rats. In this experiment of parameter, 705KHz,1W/cm2 of ultrasound exposure resulted in a significant effect on reducing intimal hyperplasia andincreased apoptosis of VSMC ,it could prevent the restenosis formation of blood vessel after balloon injury to some extent.