蛋白涂层支架携带质粒介导的一氧化氮 合酶基因预防冠状动脉球囊扩张后 再狭窄的实验研究

目的　为评价蛋白涂层金属支架携带质粒介导的诱导性一氧化氮合酶 (iNOS)基因局部转染血管壁 ,预防冠状动脉内血管成形术后再狭窄的效果。方法　金属支架涂层为胶联明胶制成。载体为去内毒素纯化pcDNA3。采用标准球囊导管技术 ,将吸附有质粒介导的人肝脏的iNOS基因(pcDNA3hepiNOS)涂层支架置入小型猪 (n =9)冠状动脉前降支中段 ,以相同方法置入单纯蛋白涂层支架做为对照组 (n =9) ,支架与血管直径之比为 1.1～ 1.3:1。结果　在支架置入后 7d ,RT PCR检测和免疫组织化学染色 ,证实在pcDNA3hepiNOS转染的血管段有iNOSmRNA的表达和iNOS蛋白生成 ,而远离器官则无基因的表达。 3个月时冠状动脉造影显示 :转染pcDNA3hepiNOS组 (n =5 )无再狭窄发生 ,而对照组均发生显著的再狭窄。组织病理学形态分析结果显示 :pcDNA3hepiNOS组新生内膜面积 (1.7± 0 .8)mm2 、平均百分狭窄面积 (2 6 .5± 7.5 ) %、平均管腔狭窄百分数 (4 1.2± 16 .5 ) % ,均较对照组小 ,对照组分别为 (2 .8± 0 .8)mm2 ,P <0 .0 5 ;(94.2± 14.3) % ,P <0 .0 0 1;(88.0± 16 .6 ) % ,P <0 .0 0 1;比较内膜面积 /中膜面积比值 (I/M)治疗组较对照组减少了 5 9.8%。结论　在小型猪模型使用蛋白涂层支架携带纯化质粒介导的iNOS基因可直接导入血管

The local transfer of plasmid-mediated human inducible nitric oxide synthase gene with protein-coated metallic stents inhibits intimal hyperplasia following coronary angioplasty in mini-swine model

Objective To assess the effect of local transfer ofplasmid-mediated inducible Nitric Oxide synthase gene using protein-coated metallic stents of inhibiting neointimal hyperplasia after coronary angioplasty. Methods The metallic stent was coated by cross-linked gelatin and mounted on 3.0 mm PTCA balloon,then endotoxin-free ultrapure plasmid pcDNA3hepiNOS was absorbed on the stent. Protein-coated stainless steel stents were used as controls. All stents were implanted into the middle segment of LAD. The ratio of balloon to vessel diameter was 1.1－1.3:1. Results At the 7th day after stenting, RT-PCR and immunohistochemical staining confirmed the expression of iNOS mRNA and presence of its protein at gene transferred vessels (n=2), but there was no expression in remote organs. After 3 months of stenting coronary angiograms showed that there was no restenosis in all animals transferred plasmid pcDNA3hepiNOS(n=5) while restenosis developed in all animals of the control group (n=5). Morphometric analysis showed that lumen diameter loss (0.61±0.30) mm vs (1.58±0.31) mm (P<0.001), residual lumen diameter (1.00±0.51) mm vs (0.36±0.32) mm (P<0.05), neointimal area (1.65±0.83) mm2 vs (2.83±0.83) mm2 (P<0.05), mean percentage of area stenosis (26.45±7.45) mm2 vs (94.2±14.3) mm2 (P<0.001) were significantly less than those in control group. The proportion of the neointimal area to media area(I/M) reduced to 59.84% in pcDNA3hepiNOS group. Conclusions Local plasmid-mediated human iNOS gene transferred with protein-coated metallic stents significantly inhibited intimal hyperplasia,which was usually a causative factor of retenosis after coronary angioplasty, in mini-swine model.