cTnT^（R141W）转基因小鼠扩张型心肌病模型的建立

目的建立cTnT^R141W扩张型心肌病的转基因小鼠模型。方法把cTnT^R141W基因插入-αMHC启动子下游,构建转基因表达载体,通过显微注射法建立cTnT^R141W转基因C57BL/6J小鼠。PCR鉴定cTnT^R141W转基因小鼠的基因表型,实时PCR检测基因的拷贝数,Northern blotting检测基因表达,光学显微镜和超声检测cTnT^R141W转基因小鼠心脏的病理改变。结果建立了3个系的cTnT^R141W转基因小鼠。3个系的基因拷贝数分别是15、20和59拷贝。cTnT^R141W基因在心脏组织的表达水平高于内源性cTnT。病理分析显示cTnT^R141W转基因小鼠心房心室明显大于野生型,心室壁明显变薄,心肌细胞不均匀肥大,心肌间质纤维增多。超声检查显示心室腔明显扩大,收缩期容积和舒张期容积显著增大,射血分数、短轴缩短率、室壁运动度明显降低。结论cTnT^R141W转基因小鼠的全心扩大,室壁变薄,心肌细胞肥大,间质纤维化以及心肌收缩力下降,说明成功建立了cTnT^R141W转基因小鼠扩张型心肌病模型,为研究扩张型心肌病发病机制和药物研发提供了有价值的动物模型。

Establishment of a cTnT^R141W Transgenic Animal Model of Dilated Cardiomyopathy

Objective To establish a cTnT^R141Wgene transgenic mouse model of dilated cardiomyopathy. Methods The transgenic plasmid was constructed by inserting the cTnT^R141W gene into the downstream of α-MHC promoter. The transgenic mice were produced by microinjection method and the genotyping was detected by PCR. The copy number of the transgenic gene was detected by real-time PCR and the expression level of the gene was determined with Northern blotting. The pathologic changes were observed by microscopy and analyzed with echocardiography. Results Three lines of transgenic C57BL/6J mouse of cTnT^R141W gene were established and the copy number of the gene was 15, 20 and 59, respectively, in the three mouse lines. The expression of the cTnT^R141W gene was detected in the heart tissues. The heart of cTnT^R141W transgenic mouse showed thinner ventrieular wall and enlarged ventrieular chamber compared with that of the wild type. The ejection fraction （ EF% ） , fractional shortening （FS%） and the movement of ventricular wall were decreased significantly. Conclusions The expression of mutant cTnT^R141W gene in heart caused ventricular chamber enlargement, myocardial hypertrophy, interstitial fibrosis, and systolic dysfunction, indicating that the cTnT^R141W gene transgenic mouse is a useful animal model of DCM.