转导C型钠尿肽基因对血管成形术后新生内膜增生及内皮功能的影响

目的 观察局部转导C型钠尿肽(CNP)基因对血管损伤后内膜增生及内皮功能的影响。方法 将84只雄性新西兰大白兔随机均分为正常、对照和实验3组。3组高脂饮食喂养,对照组和实验组以球囊损伤兔髂动脉建立动脉粥样硬化兔再狭窄模型。对照组建模后局部转导逆转录病毒载体携带的碱性磷酸酶基因,实验组建模后后局部转导逆转录病毒载体携带的CNP基因(PLXSN-CNP)。于高脂饮食喂养前及处死前检测各组血脂和血CNP水平,对损伤的髂动脉进行离体血管环张力实验, 进行病理和CNP免疫组化学检测,采用计算机图像分析仪测量动物血管管腔面积、内膜厚度、内膜面积、内膜面积/中膜面积。结果 对照组和实验组血CNP水平和血脂水平在术前和术后同一时间点比较无显著差异。实验组血管经Ach和L-Arg 预处理+Ach处理后,内皮依赖性舒张功能显著强于正常组和对照组(P<0.01) 而非内皮依赖性舒张功能各组间无显著差异(P>0.05),而经LMMA预处理+ Ach 处理后血管环舒张功能明显变差;实验组在转染局部表达CNP基因;球囊损伤后2周,实验组和对照组血管内膜面积、内膜厚度、内膜/中膜比值显著增加,但实验组显著低于对照组(P<0.01)。结论 CNP基因可成功转导损伤血管,并有效地在局限表达;局部转导CNP基因可有效抑制血管成形术后内膜增生,增进内皮功能。

Effects of C-type natriuretic peptide gene transduction on neointimal hyperplasia and endothelial function after angioplasty

Objective To investigate the effects of C-type natriuretic peptide (CNP) gene transduction on neointimal hyperpla-sia and endothelial function after angioplasty. Methods Eighty-four rabbits were divided into 3 equal groups, namely normal control group, alkaline phosphatase gene transduction group and CNP gene transduction group. The rabbits in the latter two groups were given high-cholesterol diet 7 d before the experiment, followed by establishment of restenosis models by injuring the iliac artery and the specified gene transfer via retroviral vectors. Those in the normal control group were fed with normal diet. Before high-cholesterol diet and killing respectively, 2 ml venous blood samples were taken for testing blood lipid and serum CNP concentration. In the two groups with gene transduction, the injured rabbit iliac arteries were harvested for ex vivo vascular ring tension test, histological and pathological examinations, as well as immunohistochemistry analysis of CNP. The lumen area, neointimal thickness, neointimal area, ratio of intimal to medial area were measured by image analysis system. Results There were no significant differences in blood lipid and serum CNP concentration between the two gene transduction groups at the same time points both before and after operation. In CNP gene transduction group, endothelium-dependent re-laxation of the vascular rings was significantly improved in comparison with the other two groups (P<0.01), irrespective of L-Arg pretreatment, whereas endothelium-independent relaxation function varied little between the 3 groups (P>0.05). Poor relaxation function to Ach of the vascular rings was resulted after pretreatment with LMMA. CNP gene expression at the site of gene transfer was detected in the CNP gene transduction group and in 2 weeks after balloon injury, the neointimal thick-ness, neointimal area and ratio of the neointimal to tunica media area were markedly increased in the two gene transduction groups, but the measurements were significantly lower in CNP group (P<0.01). Conclusion CNP gene can be successfully transferred and effectively expressed at the injured site in the blood vessels to decrease the hyperplasia and significantly im-prove endothelial function after angioplasty.