小鼠主动脉弓不同程度缩窄模型的评价与比较

Evaluation and comparison of transverse aortic constriction of different gradies in a mouse model

目的：采用超声多普勒的方法评价小鼠主动脉弓缩窄模型建立的成败及程度,比较主动脉弓缩窄程度对心脏形态及功能影响的差异。方法：60只雄性C57BL/6小鼠随机分成假手术组（sham组）20只,26G缩窄针主动脉弓缩窄组（TAC^26G组）20只,27G缩窄针主动脉弓缩窄组（TAC^27G组）20只,采用超声多普勒的方法检测小鼠双侧颈动脉流速,通过右侧颈动脉（right carotid arteries,RCA）流速与左侧颈动脉（left carotid arteries,LCA）流速之比（RCA/LCA）来评价主动脉弓缩窄术的成败及程度;术后2周进行超声心动图检测,并对各组心脏进行拍照,计算心重/体重及左室重/胫骨长度,比较主动脉弓不同缩窄程度对心肌肥大形成的严重程度以及心脏功能的影响。结果：与sham组相比,TAC^26G组及TAC^27G组RCA/LCA均显著上升（P〈0.05）,TAC^27G组的RCA/LCA为8-10,较之TAC^26G组（RCA/LCA为5-7）具有显著性差异（P〈0.05）。术后2周,TAC^26G组表现为向心性肥大,与sham组相比,舒张期室间隔厚度（IVSd）、舒张期后壁厚度（LVPWd）、射血分数（EF）、短轴缩短率（FS）均显著上升（P〈0.05）,左室舒张末期内径（LVIDd）显著下降（P〈0.05）;TAC^27G组表现为离心性肥大,与sham组相比,IVSd、LVPWd、LVIDd均显著上升（P〈0.05）,EF及FS均显著下降（P〈0.05）。术后2周,与sham组相比,TAC^26G及TAC^27G组心重/体重及左室重/胫骨长度均显著上升（P〈0.05）,TAC^27G组上述两个肥大指标较之TAC^26G组明显增加（P〈0.05）。结论：采用超声多普勒检测RCA/LCA在实验早期即可准确判断主动脉弓缩窄术的成败及程度,对压力超负荷心肌肥大及心力衰竭相关研究动物模型的选择具有重要的指导作用。

Objective：To evaluate the degree of pressure overload and successful ligation of transverse aortic constriction（TAC）using ultrasonic Doppler methods and investigate whether different gradient TAC made any differences in cardiac structure and function.Methods：A total of 60 male C57 / BL6 mice were randomly divided into the sham-operated group（sham,n = 20）the 26 G needle banded TAC group（TAC^26G,n = 20） and the 27 G needle banded TAC group（TAC^27G,n = 20）.The degree of pressure overload and successful ligation of TAC were determined by measuring the flow ratio defined by the right carotid arteries（RCA） / left carotid arteries（LCA）.The effect of pressure overload on cardiac structure and function due to different gradient TAC were measured by calculating the heart weight / body weight（HW / BW） and left vetricle weight / tibia length（LVW / TL） and echocardiography.Results：Doppler assays showed that the RCA / LCA was significantly increased in both TAC^26G and TAC^27G compared with sham（P〈0.05）.The ratio of RCA / LCA in TAC^27Gwas significantly different from TAC^26G（P〈0.05）.Two weeks after the operation,compared with sham,IVSd and LVPWd were significantly increased in both the TAC^26G and TAC^27Ggroup（P〈0.05）;EF and FS were significantly increased in the TAC^26Ggroup but significantly decreased in the TAC^27G group（P〈0.05）.Two weeks after the surgery,the HW / BW and LVW / TL were significantly increased in both TAC^26G and TAC^27 Gcompared with sham（P〈0.05）,and the above index were much higher in the TAC^27G group than the TAC^26G group（P〈0.05）.Conclusion：Our data revealed the relationship between carotid velocity change and cardiac hypertrophy in early the phase of transverse aortic constriction.It provided guidance on a better mouse model for pressure overload induced cardiac hypertrophy and heart failure.