人血管内皮生长因子165与嵌合水蛭肽融合基因防治兔颈动脉损伤后再狭窄的实验研究

目的观察人血管内皮生长因子165（hVEGF165）与嵌合水蛭肽融合基因（fused hirudin,FH）对兔颈动脉损伤后再狭窄的防治作用,为再狭窄的基因治疗提供新的思路。方法通过基因重组构建hVEGF。与FH的融合基因（hVEGF165-FH）。制备免颈总动脉血管成形术损伤后再狭窄模型,损伤局部转染该融合基因作为治疗组。同时局部转染pcDNA3．0空质粒作为对照组,通过血管造影、病理分析等观察融合基因是否抑制兔颈总动脉血管成形术后再狭窄。结果局部转染融合基因后1周和3周,造影显示治疗组血管狭窄程度与对照组比较显著减轻;病理分析显示。治疗组较对照组管腔狭窄程度显著减轻（1周：11．50％vs33．25％;3周：19．75％vs52．25％,P〈0．05）;治疗组较对照组内膜增生程度（内膜／中膜,I／M）显著减轻（1周：0．12vs0．50;3周：0．35vs1．07,P〈0．05）。同时融合基因对血管损伤处的血栓形成有抑制作用,但对系统凝血指标无影响,无全身出血并发症。结论融合基因hVEGF165-FH可有效地预防兔颈动脉成形术后再狭窄。以内皮修复为基础,构建双靶点甚至多靶点的融合基因可能是未来再狭窄防治的一个有效策略。

Effects of fusion gene encoding the hVEGF165 and fused hirudin on restenosis of injured carotid artery induced by angioplasty

OBJECTIVE: To study the effects of fusion gene encoding the hVEGF(165) and fused hirudin on restenosis of injured carotid artery. METHODS: A fusion gene encoding hVEGF(165) and fused hirudin (hVEGF(165)-FH) was constructed and clone into the eukaryotic expression vector pcDNA3.0, thus constructing the plasmid VEGF(165)-FH/pcDNA3.0. Its activities to stimulate endothelial cell proliferation and to inhibit thrombosis were identified. Sixteen New Zealand rabbits underwent ligation of external carotid artery and a balloon was inserted into the common carotid artery for 30 minutes so as to construct model of restenosis of injured carotid artery. Then the rabbits were randomly divided into 4 equal groups. In the one-week and 3-week control groups, 400 microg of DNA of the plasmid pcDNA3.0 were transfused into the arterial lumen at the injured part immediately after the angioplasty, and 400 microg of DNA of the plasmid VEGF(165)-FH/pcDNA3.0 were transfused in the 1-week and 3-week experimental groups. One week and 3 weeks after the treatment peripheral blood samples were collected to detect the activated partial thromboplastin time (APTT), thrombin time (TT), and platelet aggregation rate, and then the rabbits underwent angiography to observe the situation of restenosis. Then the rabbits were killed to take out the injured part of artery to undergo pathological examination and Western blotting. RESULTS: The values of APTT, TT, and platelet aggregation rate were not significantly different among the 4 groups. Angiography conducted 1 and 3 weeks later showed that restenosis was significantly mild in the 2 experimental groups in comparison with the 2 control groups, and severe restenosis was seen in the 3-week control group. Western blotting showed that expression of specific fused protein could be found in the 1-week and 3-week experimental group, the amount of the latter group being less than that of the former group; however, no expression of specific fused protein was found in the 2 control groups. Pathological examination showed that the narrowing of lumen 1-week and 3-week experimental groups were 11.50% and 19.75%, both significantly milder than those of the 1-week and 3-week control groups (33.25% and 52.25% respectively, both f P < 0.05). VB staining showed that the (intima/media (I/M) ratio of the 1-week and 3-week experimental groups were 0.12 and 0.35 respectively, both significantly lower than those of the 2 control groups (0.50 and 1.07 respectively, both P < 0.05). CONCLUSION: Accelerating re-endothelialization and inhibiting thrombosis, the fused gene hVEGF(165)-FH effectively prevents restenosis after angioplasty, On the basis of endothelial repair, construction of fused genes with double even multiple targets may be a novel and potential therapeutic approach for restenosis after percutaneous coronary intervention.