超声靶向微泡破坏介导心肌梗死后左心室结构重构和神经重构的实验研究

Effect of ultrasound targeted microbubble destruction mediated left ventricular structural and sympathetic remodeling in myocardial infarction

目的探讨超声靶向微泡破坏(UTMD)介导血管生成素1(Ang1)基因转染促进血管生成,逆转心肌梗死(MI)犬左心室结构及交感神经重构的效果。方法 30只清洁级雄性成年杂种犬,体质量15.0~21.0 kg,平均体质量17.1 kg。随机分为3组,每组各10只,即对照组(健康犬)、MI组(MI造模后未进行UTMD治疗的犬)和UTMD组(MI造模后进行UTMD治疗的犬)。1个月后用超声心动图测定左心室结构及收缩功能,二维超声斑点追踪成像(2D-STI)评价左心室局部和整体收缩同步性。免疫组织化学技术检测新生毛细血管密度、心室肌酪氨酸羟化酶(TH)和生长相关蛋白43(GAP43)阳性神经分布和密度。Western blot检测Ang1、TH和GAP43蛋白表达水平。结果与MI组相比,UTMD组左心室收缩末期内径减小,左心室射血分数、短轴缩短率增加,左心室局部应变增强,整体同步化程度增加。UTMD组新生毛细血管密度高于MI组,而TH和GAP43在MI组中升高,在UTMD组中降低。Western blot显示,与对照组和MI组相比,UTMD组Ang1蛋白升高[(50.5±13.8)%vs(12.6±4.7)%,t=8.2,P <0.05;(50.5±13.8)%vs (15.5±4.6)%,t=6.4,P <0.05],但TH和GAP43较MI组低[(22.5±6.7)%vs(41.3±9.5)%,t=4.5,P <0.05;(18.5±3.2)%vs(32.6±8.8)%,t=4.2,P <0.05]。结论 UTMD介导Ang1转染不仅可以促进MI后血管生成,而且可以逆转左心室结构重构和交感神经重构,有效改善左心室同步性。

Objective To investigate the effect of ultrasound-targeted microbubble destruction(UTMD)-mediated angiopoietin 1(Ang1) gene transfection on angiogenesis, reverse left ventricular structure and sympathetic remodeling in myocardial infarction(MI) canines. Methods A total of 30 clean male adult mongrel canines(body weight 15.0-21.0 kg with mean body weight of17.1 kg) were randomly divided into 3 groups(n = 10) which were control group(healthy), MI group(MI without UTMD) and UTMD group(MI with UTMD). The left ventricular structure and systolic function were measured by echocardiography, the left ventricular local and global synchronization parameters were evaluated by two-dimensional echocardiography speckle tracking imaging after 1-month. The immunohistochemical technology was used to detect angiogenesis capillary, distribution and densities of tyrosine hydroxylase(TH) and growth associated protein 43(GAP43) positive nerve in ventricle. The protein expression level of Ang1, TH and GAP43 were detected by Western blot. Results Compared with MI group, the left ventricular endsystolic diameter was decreased, the left ventricular ejection fraction, short-axis shorten rate and local strain of left ventricle was enhanced, the degree of global synchronization was increased in UTMD group. The density of angiogenesis in UTMD group were higher than that in MI group, while TH and GAP43 were increased in MI group, but decreased in UTMD group. Western blot results showed that compared with control group and MI group, Ang1 protein increased in UTMD group[(50.5 ± 13.8) % vs(12.6 ± 4.7) %, t = 8.2, P < 0.05;(50.5 ± 13.8) % vs(15.5 ± 4.6) %, t = 6.4, P < 0.05], while TH and GAP43 in UTMD group were lower than that in MI group[(22.5 ± 6.7) % vs(41.3 ± 9.5) %, t = 4.5, P < 0.05;(18.5 ± 3.2) % vs(32.6 ± 8.8) %, t =4.2, P < 0.05]. Conclusion It is demonstrated that UTMD-mediated Ang1 transfection can promote angiogenesis after MI,and reverse left ventricular structural remodeling and sympathetic remodeling, which effectively improve left ventricular synchrony.