cTnT^(R92Q)转基因小鼠肥厚型心肌病模型的建立

The Establishment of the cTnT^(R92Q) Transgenic Mouse Model of Hypertrophic Cardiomyopathy

目的建立cTnTR92Q肥厚型心肌病的转基因小鼠模型。方法把cTnTR92Q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cTnTR92Q转基因C57BL/6J小鼠。PCR鉴定cTnTR92Q转基因小鼠的基因表型,RT-PCR检测基因表达,光学显微镜和超声检测cTnTR92Q转基因小鼠心脏的病理改变。结果建立了3个不同表达水平的cTnTR92Q转基因小鼠品系。转入的cTnTR92Q基因在心脏组织的表达水平高于内源性cTnT。组织学分析显示cTnTR92Q转基因小鼠心脏变大,心室壁肥厚,心腔变小,心肌细胞排列紊乱,心肌间质纤维增多。超声检查显示心室壁变厚,收缩期容积和舒张期容积显著缩小,射血分数、短轴缩短率明显增加。结论cTnTR92Q转基因小鼠心脏变大,室壁变厚,心腔变小,心肌细胞排列紊乱,间质纤维化以及心肌舒张功能失调,说明成功建立了cTnTR92Q转基因小鼠肥厚型心肌病模型,为研究肥厚型心肌病发病机制和药物研发提供了有价值的动物模型。

Objective To establish the transgenic mouse of cTnT^R92Q gene to make an animal model of hypertrophic cardiomyopathy （HCM）. Methods The transgenic plasmid was constructed by inserting the cTnT^R92Q gene in the downstream of α-MHC promoter. The transgenic mice were produced by micreinjection method and the genotype was detected by PCR. The expression level of the gene was determined with RT-PCR. The pathologic changes were observed under microscope and analyzed with echocardiography. Results Three lines of transgenic C57BL/6J mouse of cTnT^R92Q gene with different expression levels were established. The expression of the cTnT^R92Q gene was obviously detected in the heart tissues. The heart of cTnT^R92Q transgenic mouse showed hypertrophic ventricular wall, reduced ventricular chamber, myocyte disarray, and interstitial fibrosis compared with that of the wild type. The Ejection fraction （EF%） and Fractional shortening （FS%） were increased obviously. Conclusions The expression of mutant cTnT^R92Q gene in heart caused ventricular chamber reducing, myocardial hypertrophy, myocyte disarray, interstitial fibrosis, and diastolic dysfunction, which suggest that the cTnT^R92Q gene transgenic mouse is an useful animal model of HCM.