微泡造影剂结合超声介导一氧化氮合成酶基因转染防治移植静脉再狭窄

Ultrasound combined with microbubble contrast agent-mediated nitric oxide synthase gene transfer prevents restenosis of vein graft

目的探讨微泡造影剂及超声辐照介导内皮型一氧化氮合成酶（eNOS）基因转染防治移植静脉血管桥再狭窄的可行性。方法重组真核表达载体pcDNA3．1-eNOS经微泡造影剂及超声辐照介导体外转染大鼠颈外静脉，再将静脉段间置植入颈总动脉，建立SD大鼠颈外静脉-颈总动脉移植模型。于术后4周取移植静脉标本分别进行苏木素-伊红（HE）染色，免疫组织化学染色及Westernblot法分析，观察eNOS基因在静脉桥中的功能表达和静脉桥新生内膜的增生。结果Westernblot法分析表明微泡造影剂及超声辐照介导eNOS基因转染组的移植血管桥内eNOS表达最明显；增殖细胞核抗原（PCNA）检测阳性率为（21．04±3．51）％，细胞凋亡指数为（12．11±1．23）％，新生内膜厚度（25．0±3．5）μm，内膜／中膜比值为0．43，均明显低于其他组（P〈0．05）。结论微泡造影剂及超声辐照介导eNOS基因转染可以有效抑制移植静脉桥新生内膜的增生。

Objective To investigate the feasibility and efficacy of ultrasound combined with mi- crobubble contrast agent-mediated nitric oxide synthase gene transfer preventing and treating restenosis of vein graf. Methods Sprague-Dawley rats underwent interposition grafting of the common carotid artery via the ipsilateral external jugular vein. Before anastomosis, the vein segment was put into the solutions with microbubbles which were adhered with the plasmid of pcDNA3. 1-endothelial nitric oxide synthase （eNOS）. Pulsed Doppler ultrasound was used for 10 min. The grafts were harvested at 28th day after surgery. The vessels were observed with hematoxylin-eosin staining, immunohistochemical staining and Western blotting to evaluate the extend of re-stricture of the vessels. Results Western blotting revealed that the expression of eNOS in plasmid ＋ ultrasonic irradiation ＋ microbubble contrast agent group was strongest. In plasmid ＋ ultrasonic irradiation ＋ microbubble contrast agent group, proliferating cell nuclear antigen （PCNA） -positive detection rate was （21.04±3.51 ） %, apoptotic index was （ 12. 11±1.23 ） %, neointi- real thickness was （25.0±3.5 ）μm, and intimal/medial ratio was 0. 43, which were significantly reduced as compared with other groups （P 〈 0.05）. Conclusion Ultrasound combined with microbubble contrast agent-mediated eNOS gene transfer can inhibit the vein graft neointimal hyperplasia.