超声激活携基因微泡对碱性成纤维细胞生长因子在梗死心肌中表达的影响

Basic fibroblast growth factor delivered by ultrasound-mediated destruction microbubbles for treatment of acute myocardial infarction

背景:很多实验表明超声破坏携基因微泡能增强组织中基因的表达,是一种可向组织递送基因的途径。目的:验证超声激活携基因微泡对碱性成纤维细胞生长因子在梗死心肌组织中表达的影响及其治疗鼠急性心肌梗死的可行性。设计、时间及地点:随机对照动物实验,于2007-09/2008-10在重庆医科大学超声影像学研究所和超声医学工程研究所完成。材料:重组人碱性成纤维细胞生长因子质粒构建由美国芝加哥大学医学中心构建馈赠,表达24ku蛋白质的人碱性成纤维细胞生长因子基因编码区通过PCR扩增后亚克隆至pAdTrace-TO4,该质粒载体还携带有红色荧光蛋白。方法:健康SD大鼠60只随机均分为3组:对照组、单纯基因组和超声介导基因组。通过结扎冠状动脉前降支制作急性心肌梗死模型,造模后,超声介导基因组于心肌内注射携基因微泡50μL后行超声辐照,单纯基因组和对照组分别注射50μL携基因微泡和生理盐水。主要观察指标:4周后观察心肌组织中荧光强度和碱性成纤维细胞生长因子蛋白表达水平,并行血流动力学、微血管密度及血管梗死面积检测。结果:①超声激活携基因微泡可使心肌内外源基因表达水平提高6倍以上(P<0.05)。②与对照组相比,单纯基因组血流动力学结果明显改善,但超声介导基因组血流动力学改善更明显(P<0.05);与单纯基因组相比,超声介导基因组血管新生、梗死面积缩小更明显(P<0.05)。结论:超声激活携基因微泡能明显增加碱性成纤维细胞生长因子基因在梗死心肌的表达,是治疗心肌梗死的一种可行方法。

BACKGROUND： Many experiments have suggested that ultrasound-mediated microbubble destruction can enhance expression of gene in the tissue; this is a pathway to deliver gene to the tissue. OBJECTIVE： To investigate expression of basic fibroblast growth factor （bFGF） gene in ischemic myocardium by ultrasound-mediated microbubble destruction, and to explore its feasibility for the therapy of myocardial infarction. DESIGN, TIME AND SETTING： Randomized controlled animal experiment was performed in the Institute of Ultrasound Image and the Institute of Ultrasound Engineering of Chongqing Medical University from September 2007 to October 2008. MATERIALS： rh-bFGF was prepared and graciously provided by The University of Chicago Medical Center; bFGF gene coding region that expressed 24 ku proteins was subcloned to pAdTrace-TO4 by PCR amplification, and this plasmid vector carried red fluorescent protein. METHODS： Sixty healthy SD rats were randomly assigned into control, gene and ultrasound mediated gene groups. Models of acute myocardial infarction model were made by ligation of the left anterior descending coronary artery, A volume of 50 μ L microbubbles attached rh-bFGF was administered into the tissue by intramyocardial injection with ultrasound exposure in the ultrasound mediated gene group. Rats in the control and gene groups were infused with 50 μ L normal saline. MAIN OUTCOME MEASURES： The fluorescence intensity, expression of bFGF protein and hemodynamics were detected at 4 weeks after treatment. Masson＇s staining and factor Ⅷ immunohistochemisty were used to detect the infarction size and the angiogenesis. RESULTS： The expression of bFGF protein was 6-fold higher in the ultrasound mediated gene group than other groups （P〈 0.05）. The hemodynamics was obviously improved in the gene group, but the improvement was the best in the ultrasound mediated gene group （P 〈 0.05）. Compared with gene group, ultrasound mediated gene could facilitate the angiogenesis and decrease the infarction size （P 〈 0.05）. CONCLUSION： Ultrasound-mediated microbubble destruction can effectively enhance the expression of bFGF gene into the infarcted myocardium of rats. It is a promising method for therapy of myocardial infarction.