超声成像技术分析糜酶转基因小鼠心脏功能

Analysis the Heart Function of Human Chymase Gene Transgenic Mouse with Echocardiography

目的应用小动物高频超声技术对糜酶转基因小鼠的心功能进行分析,以探索糜酶基因对心脏结构和功能的影响。方法通过VisualSonics Vevo770高分辨率小动物超声系统检测不同年龄的转基因小鼠及对照小鼠包括心壁厚度、主动脉血流速度、左心室内径、左心室容积、每搏输出量、射血分数、短轴缩短率和心输出量等的心脏功能指标的改变进行比较分析。结果随着小鼠年龄的增大,转基因阳性小鼠心壁厚度和主动脉血流速度逐渐增加,至6月龄时,转基因小鼠的左心室前壁收缩期厚度增加37%,增长率是对照小鼠的1.2倍(P<0.05);主动脉血流速度比对照小鼠高29%(P<0.05);转基因阳性小鼠的左心室内径、左心室容积、每搏输出量、射血分数、短轴缩短率和心输出量等的心脏功能指标表现出和以上变化相一致的表型。结论转基因小鼠糜酶表达水平升高,引起心脏AngⅡ形成增多,可使心肌细胞的收缩力提高;心肌细胞肥大,心壁增厚;且有随年龄增加的趋势,可研究建立慢性、老年性肥厚型心脏病模型。

Objective To analyze the function of human Chymase gene in heart in the transgenic mouse. Methods The heart function of the transgenic mice and the wild type mice were analyzed by echocardiography with Vevo770 at different ages, including LVAW, LVPW, aortic velocity, Diameter, Volume, Stroke volume, Ejection fraction, Fractional shortening, Cardiac output. Results The heart function of the transgenic mice and the wild type mice were analyzed at 1 month old, 2 months old, 4 months old and 6 months old. The LVAW of transgenic heart was increased up to 37 % and the increasing rate of the transgenic heart was 1.2 fold of the control heart （P 〈 0.05） at 6 months old. The aortic velocity of transgenic mice was increased at 4 months old compared with the wild type mice （ P 〈 0.05）, and the increasing was 29% higher than the control mice （ P 〈 0.05）. The function of the transgenic hear on Diameter, Volume, Stroke volume, Ejection fraction Fractional shortening and Cardiac output was also changed corresponding with the increasing of LVAW and aortic velocity. Conclusion Our results suggested that the expression of human Chymase gene in heart tissue of mouse caused the increasing of Ang Ⅱ and resulted in the hypertrophy of myocardiocytes, the increasing of LVAW and LVPW with aging. This transgenic mouse could be used as a hypertrophic cardiomyopathy model.