人心肌肌钙蛋白C两种突变转基因小鼠模型建立与对比分析

Establishment of two cardiac-specific human cardiac troponin C mutation transgenic mice and comparative analysis

目的为建立心肌组织特异性表达人cTnCD145E和cTnCG159D突变基因转基因小鼠,为对比分析两种不同心肌病的发生发展建立模型。方法利用定点突变技术分别制备人cTnC基因的cTnCD145E和cTnCG159D两个突变体,随后插入心肌特异性表达启动子α-MHC下游构建人cTnCD145E和cTnCG159D基因转基因载体。通过显微注射法建立转基因C57BL/6小鼠。利用心脏超声和病理观察对比分析不同年龄转基因小鼠心脏的结构与功能。结果建立了心肌组织高表达人cTnCD145E和cTnCG159D突变基因转基因小鼠,cTnCD145E和cTnCG159D转基因小鼠随年龄增加,有分别向HCM和DCM发展的趋势,12月龄时,cTnCD145E转基因小鼠收缩末期和舒张末期左室容积(left ventricle end-diastolic volume and end-systolic volume,EDV and ESV)与同窝阴性小鼠相比下降,射血分数(ejection fraction,EF)和收缩末期左心室后壁厚度(left ventricle end-systolic posterior wall thickness,ESPWT)增加,而cTnCG159D转基因小鼠EDV和ESV与同窝阴性小鼠相比上升,EF和ESPWT减少。结论心肌组织特异性表达人cTnCD145E突变基因转基因小鼠表现肥厚型心肌病病理表型,而心肌组织特异性表达人cTnCG159D突变基因转基因小鼠表现扩张型心肌病病理表型,二者可作为对比研究由不同发病机制导致的心肌病模型。

Objective To established cardiac-specific transgenic mice of the cTnC D145E and cTnCG159D and compare the HCM and the DCM.Methods The cTnCD145E and cTnCG159D were generated by site-directed mutagenesis and the transgenic plasmids were constructed by insertion of the mutant genes under the control of α-MHC, which is a myocardium specific promoter.The transgenic mice were generated by microinjection and were all maintained on a C57BL/6J genetic backgroud .The cardiac structure and function of the transgenic mice were compared and analysized by echocardiographic and pathological observation at different ages .Results The cTnCD145E and cTnCG159D transgenic mice were established and developed to HCM and DCM, respectively, with aging.The left ventricular end-systolic volume （ESV） and left ventricular end-diastolic volume （ EDV） decreased and ejection fraction （ EF） and left ventricular end-systolic posterior wall thickness （ESPWT） increased in the cTnCD145E transgenic mice, while EDV and ESV increased and EF and ESPWT decreased in the cTnCG159D transgenic mice at 12 months of age.Conclusions Cardiac-specific human cTnCD145E transgenic mice showed HCM phenotypes , and cardiac-specific human cTnC G159D transgenic mice showed DCM phenotypes , which can be used as different models for comparative study of the pathogenesis of cardiomyopathy .