rAAV介导血管生长素基因转染改善心肌梗死大鼠左室重构

rAAV Mediated Angiogenin Gene Transfer Improving Left Ventricular Remodeling in Rats with Myocardial Infarction

目的观察腺相关病毒介导的血管生长素(ANG)基因转染对心肌梗死(MI)大鼠左室心肌组织ANG蛋白表达、毛细血管密度和左室重构的影响。方法成年雄性Wistar大鼠,随机分为假手术组(sham-operation)、心肌梗死心肌内注射rAAV-lacZ组(MI-rAAV-lacZ)和心肌梗死心肌内注射rAAV-ANG组(MI-rAAV-ANG)。直视下结扎冠状动脉左前降支建立MI模型,冠脉结扎后立即取rAAV-lacZ或rAAV-ANG梗死区周围四个点注射。四周后处死大鼠,左室称重,计算左室重量与体重比值。Western blot方法检测心肌组织ANG蛋白表达水平;免疫组化方法检测vWF表达以评价心肌组织毛细血管密度;组织学切片上测量非梗死区心肌细胞的横径和心肌间质纤维沉积指数。结果与sham-operation组和MI-rAAV-lacZ组相比,MI-rAAV-ANG组大鼠左室心肌组织ANG水平显著升高;左室非梗死区毛细血管密度在MI-rAAV-lacZ组大鼠显著下降,而MI-rAAV-ANG组则与sham-operation组无显著差异;MI-rAAV-lacZ组大鼠表现出显著的左室非梗死区重构,包括左室重量增加、非梗死区心肌细胞横径增加、心肌间质纤维沉积增多,这些指标在MI-rAAV-ANG组与sham-operation组之间无显著差异。结论用心肌内注射方式转染rAAV-ANG可显著上调MI大鼠左室心肌ANG蛋白表达,诱导新血管生成,改善MI后左室重构。

Objective To test the hypothesis that intramyocardial injection of a recombinant adeno-associated virus vector encoding the ANG gene （rAAV-ANG） can augment therapeutic neovascularization, leading to restoration of left ventricular remodeling in rats with myocardial infarction （MI）. Methods Adult male Wistar rats were randomly divided into 3 groups, designated sham-operation, MI- rAAV-lacZ and MI-rAAV-ANG. MI rat model was generated with ligation of left anterior descending coronary artery. Immediately after the ligation, rAAV-lacZ or rAAV-ANG was injected into myocardium around the infarction area. Four weeks later, rats were killed and left ventricles were weighed, western blot was performed to detect myocardium ANG protein level, immunohistochemistry to vWF was performed to evaluate myocardium capillary density, and cardiomyocyte diameter and interstitial fibrosis were evaluated on histological slices. Results Compared with sham-operation and MI-rAAV-lacZ groups, myocardium ANG protein level was significantly increased in MI-rAAV-ANG group. Compared with sham-operation group, myocardium capillary density in noninfarction area was markedly decreased in MI-rAAV- lacZ group and showed no significant alteration in MI-rAAV-ANG group. Compared with sham-operation rats, marked left ventricular remodeling was observed in rats of MI-rAAV-lacZ group, as was indicated by increased left ventricular weight, cardiomyocyte diameter and interstitial fibrosis. While in MI-rAAV- ANG group, no significant alterations of left ventricular weight, cardiomyocyte diameter and interstitial fibrosis were found. Conclusion Intramyocardial injection of rAAV - ANG increases myocardium ANG protein expression, induced angiogenesis and inhibits left ventricular remodeling in noninfarction area.