The authors have nothing to disclose.

该协议遵循华盛顿大学的机构动物护理和使用委员会的指导方针。 1.手术过程和准备成像<ol><li>受试者C57BL / 6小鼠，以TAC或假手术，如前所述10。 </li><li> TAC或假手术后一周，麻醉小鼠中，用2％异氟烷以1L /分钟的 O 2混合感应腔室。通过确认适当反应迟钝麻醉脚趾或尾部捏。使用于眼部兽医药膏，以防止干燥时的麻醉下。通过应用脱毛膏取出胸毛。消毒用70％乙醇的小鼠皮肤。 </li><li>固定鼠标向动物处理平台在仰卧位。维持麻醉的一个稳定的水平，可使用鼻锥提供0.5 - 1％异氟烷以1L /分钟的 O 2混合。 </li><li>应用电极凝胶的小鼠的爪和它们胶带将电极焊盘。 </li><li>插入直肠探头监测体温。通过加热垫或灯保持体温在37℃。 </li><li>应用预热超声凝胶层到鼠标胸部，主要区域覆盖心脏。注意:删除超声凝胶和成像过程干燥后用无菌纱布鼠标。 </li></ol> 2.在主动脉弓查看，使用B模式和多普勒成像评价横向主动脉缩窄<ol><li>使用B模式设置获得以显现主动脉，主要动脉分支，并且缩颈部位主动脉弓图。 <ol><li>倾斜平台上来尽可能的左侧旋转鼠标放到左侧卧位。握住支架上的超声换能器的垂直位置，并将其放置在沿着正确的胸骨旁线胸前，朝向鼠标的下巴指向缺口。注意:不要压缩鼠标胸廓降低TRANSD时ucer;需要的压力最小量。 </li><li>倾斜传感器上在肩胛骨的水平并顺时针旋转略微直到主动脉弓进入图。观察横向主动脉缩窄位点，其位于无名动脉（IA）和左颈总动脉（LCCA）（ 图1）的分支之间。 注:假手术鼠标未检测到收缩。 </li></ol></li><li>点击工作站上的"彩色多普勒"按钮切换到彩色多普勒模式，以监控整个收缩部位的血液流动的方向和速度。获取并点击"电影商店"按钮保存图像。 </li><li>点击"脉冲多普勒"按钮，切换到脉冲波的多普勒模式，地方样本量（虚线光标框）立即远端狭窄网站搜索最高速度狭窄喷射，然后单击"PW多普勒"按钮获得主动脉佛罗里达州的波形流动并测量峰值速度（ 图2）。 </li><li>计算使用改性伯努利方程跨网站收缩压力梯度:压力梯度= 4×2V 以下 2。仅包括与压力梯度范围从40到80毫米汞柱用于进一步分析的小鼠。 </li></ol> 3.在胸骨旁长轴切面，使用B模式和M模式成像来评估心脏尺寸和收缩<ol><li>用鼠标躺在平台上的仰卧位，保持与缺口指向鼠标的头部在垂直的方式换能器。降低对平行于左胸骨旁线胸廓的换能器和逆时针旋转30°。 </li><li>使用B型成像，以获得心脏的一个完整的长轴"矢"的看法。调整换能器的角度和聚焦深度的可视化左心室，脑室间隔墙，以及右心室壁的轻微的部分。小号AVE图像购买心脏壁的厚度和腔室尺寸的测量。用"心套餐"，选择参数，如IVS或LVAW，LVID和LVPW，然后点击图片绘制相应行的每个参数，以获得测量结果。 </li><li>观察心脏室壁运动模式，并检查可能存在的运动异常，包括运动不能，运动功能减退，以及异步。 注意事项:运动不能和运动功能减退表示心脏壁的运动完全和部分损失分别。异步表示不规则，不协调的心脏室壁运动。 </li><li>切换到M模式，地点M型光标垂直于左心室壁在乳头肌水平，并获得用于心脏尺寸和缩短分数（ 图3）的后面测量图像。 </li></ol> 4.在胸骨旁短轴视图中，使用B型和M型成像，以评估心脏形态和功能<ol><li>神父OM胸骨旁长轴切面，通过换能器顺时针旋转90°旋转获得胸骨旁短轴观。调整换能器，得到的横截面"横向"在B模式心脏的图，这两个乳头肌清楚可见，位于右侧（在2和4点的位置）。 </li><li>切换到M型，并将M型轴在左心室的级别中旬。获取和存储图像供以后心脏壁厚，腔尺寸和短轴缩短率（ 图4）测量。用"心套餐"，在SAX（短轴），包括IVS或LVAW，LVID和LVPW，并在图像上单击选择参数绘制相应的线对每个参数，以获得测量结果。 注意:此处获得的测量应在胸骨旁长轴视图（ 图5）获得的那些密切相关。 </li></ol> 5.在心尖四腔心切面，用多普勒显像评估收缩与舒张功能<ol><li>获得心尖四腔视图与在屏幕的底部的心房形象化左，右心室。在B模式中，从短轴视图，向下倾斜平台的左上角角鼠标的头部和定向换能器朝鼠标的右肩。这实质上是实现了心脏抬头朝顶点的"冠"的看法。 </li><li>可视化B模式二尖瓣，并切换到彩色多普勒模式，放置在二尖瓣的末端的样品体积（虚线光标框）。 </li><li>切换到脉冲多普勒模式，以评估跨二尖瓣流动模式。对齐平行于二尖瓣血液流动的方向的多普勒探头光标。使用探针角度小于20°，以确定峰值速度（ 图6）。 </li><li>保存图像供以后的测量。用"心包"，然后选择"MV流"点击各参数，并绘制相应行获得的测量可用测量包括:E峰速度（年初主动心室舒张充盈），峰值速度（与心房收缩晚期充盈），二尖瓣等容舒张和收缩时间（IVRT和IVCT分别），和喷射时间（ET）。 </li><li>通过计算MPI =（IVCT + IVRT）/ ET心肌的性能指数（MPI）。 </li></ol>动物6.后处理程序<ol><li>得到的镇痛和/或无菌盐水腹膜内手术的动物需要时。 </li><li>让动物在俯卧位加热垫恢复。无人看管，直到它已经恢复了足够的意识，以保持胸骨斜卧不要让动物。不返回已经历的过程，以公司的其他动物，直到完全恢复的动物。 </li></ol>

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This work was supported in part by NIH/NHLBI grants R00HL0908076 and R01HL116507 (to Q.L.).

超声心动图已被广泛用于评估心脏疾病2,6的啮齿动物模型的心脏功能。相比于侵入或终端的方法，如压力容积环测量11和体外工作心脏12，超声心动图提供了强大的，非侵入性工具来评估在动物活体心脏正在进行结构和功能的改变。获得可靠的数据，通过仔细调节加热装置和麻醉水平保持体温和心脏速率生理范围13内是很重要的。所有图像应该始终根据标准的成像程序被捕获和分析，以方便不同株或基因型的小鼠的比较。 TAC是常用的在小鼠中诱导1心脏肥大和心脏衰竭。在由多普勒收缩现场压力梯度的无创测量摄像表示小鼠压力超负荷的程度的可靠评估。成功的TAC通常产生压力梯度≥40毫米汞柱。只受到类似程度压力超负荷的小鼠应包含用于进一步的分析，同时用压力梯度过低或过高的小鼠应排除在外。以下TAC，将小鼠有望发展1-2周内心脏肥大和心脏扩张后4周，这取决于压力负荷的程度和受试小鼠的遗传背景。动态心脏重构和以下TAC功能的改变可以如上所述被可靠地通过超声心动图显像评估。 相反，在人体14的频繁使用，彩色/脉冲多普勒刚推出不久啮齿类超声成像9可用。在这里，我们也描述多普勒成像的应用测量压力梯度以及收缩和舒张性能。测量二尖瓣和三尖瓣血流方向和速度而定（ 即 ，E / A比值，等容舒张，IVCT，ET，和MPI）提供了对心脏功能的重要信息。因此，超声心动图成像表示，研究心脏生理和病理生理小动物的一个重要工具。 心脏超声成像的限制是相关的测量变异和重现性。以减少操作员间和分子内的变异，对标准化的图像是如何获取和分析是很重要的。测量应该从多个声窗和模式（B模式，M模式，和PW /彩色多普勒）和至少3个独立的测量来执行应平均以确保准确性和可靠性。此外，也有限定声窗时低质量的图像中进行外科手术，例如交，由于组织肿胀，手术疤痕，肺水肿，与超声干涉小啮齿动物获得梁。对于多普勒成像，有时是具有挑战性的独立E和A峰并获得二尖瓣血流，完整的波形因小老鼠比较高的心脏率，尤其是在遭受TAC或心肌梗死手术老鼠。降低的心脏速率可能有助于获得测量，但是这会影响通过多普勒成像，因此数据解释所获得的值。 随着近年来技术的进步，新发布的超声波系统提供高图像分辨率和帧/采样率，以确保小动物精确的定量测量。新超声技术也将改善心脏功能的超声心动图评估的灵敏度并允许早期检测心脏的病理。例如，斑点追踪应变成像15已被用来精确地测量局部心肌功能。目前正在开发的新的换能器的技术将提供用于实时的3D或4D中的潜在成像。超声造影是在先进的开发将使体积测量，组织灌注的评估，心血管疾病的分子成像和治疗药物的交付。

Mouse models of heart disease, such as TAC and myocardial infarction (MI), have been proven to be valuable to study disease mechanisms as well as to develop novel therapeutic strategies3. TAC initially induces compensatory hypertrophy, but prolonged pressure overload leads to cardiac dilatation and heart failure4. The tightness of the aortic constriction directly determines the degree of cardiac hypertrophy and its transition to heart failure. Noninvasive and reliable measurement of pressure gradient across the aortic constriction is essential for the success of these studies. Doppler imaging has been used to assess pressure gradient produced by TAC5, which is a noninvasive alternative for catheter-based pressure measurement.
Echocardiography has been widely used to noninvasively measure cardiac morphology as well as systolic and diastolic function in mice6-8. Two-dimensional B-mode imaging is used to detect abnormal movements or structural changes of the heart. One-dimensional M-mode imaging is used for quantification of cardiac dimensions and contractility. Color and PW Doppler imaging has recently been used on rodent ultrasound, which has broad applications for echocardiography, including measurement of flow directionality and velocity, as well as systolic and diastolic performance9. 
Longitudinal real-time monitoring of cardiac function using echocardiography in B-mode, M-mode, color and PW Doppler mode provides comprehensive assessment of cardiac structure and function in mice under physiological and pathological conditions. Here we provide a detailed description of the use of echocardiographic imaging to monitor dynamic cardiac morphological and functional changes in mice following TAC or sham surgery.

<table border="0" cellpadding="0" cellspacing="0" width="1022">
	<tbody>
		<tr height="41">
			<td height="41" style="height:41px;width:339px;">Anesthesia equipment</td>
			<td style="width:343px;">Harvard Apparatus, 84 October Hill Road 
			Holliston, MA</td>
			<td style="width:175px;">723015</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:339px;">Vevo 2100 Imaging System</td>
			<td style="width:343px;">VisualSonics Inc., 3080 Yonge Street Suite 6100, Box 66, Toronto, Ontario, Canada</td>
			<td style="width:175px;">Vevo 2100</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:339px;">Aquasonic ultrasound gel</td>
			<td style="width:343px;">Parker Laboratories, 286 Eldridge Rd, Fairfield, NJ&#160;</td>
			<td style="width:175px;">03-50</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:339px;">Isoflurane</td>
			<td style="width:343px;">Piramal Healthcare, Inc, 3950 Schelden Circle 
			Bethlehem, PA&#160;</td>
			<td style="width:175px;">NDC 66794-017-25</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:339px;">F/air anesthesia gas filter unit</td>
			<td style="width:343px;">A.M. Bickford, Inc, 12318 Big Tree Rd, Wales Center, NY&#160;</td>
			<td style="width:175px;">80120</td>
			<td></td>
		</tr>
	</tbody>
</table>

assessment of cardiac morphological and functional changes in mouse model of transverse aortic constriction by echocardiographic imaging

Transverse aortic constriction (TAC) in mice has been used as a valuable model to study mechanisms of cardiac hypertrophy and heart failure1. A reliable noninvasive method is essential to assess real-time cardiac morphological and functional changes in animal models of heart disease. Transthoracic echocardiography represents an important tool for noninvasive assessment of cardiac structure and function2. Here we used a high-resolution ultrasound imaging system to monitor myocardial remodeling and heart failure progression over time in a mouse model of TAC. B-mode, M-mode, and Doppler imaging were used to precisely assess cardiac hypertrophy, ventricular dilatation, and functional deterioration in mice following TAC. Color and pulse wave (PW) Doppler imaging was used to noninvasively measure pressure gradient across the aortic constriction created by TAC and to assess transmitral blood flow in mice. Thus transthoracic echocardiographic imaging provides comprehensive noninvasive measurements of cardiac dimensions and function in mouse models of heart disease.

图1示出了进行假（ 图1A）的小鼠心脏或TAC手术（ 图1B）的主动脉弓视图的B模式图像。主动脉弓，无名动脉，左颈总动脉和左锁骨下动脉被示出。需要注意的是主动脉缩窄是TAC清晰可见，但不假心脏。从主动脉视图彩色多普勒图像示于图2A。穿过缩颈部位的主动脉流的波形是由脉冲多普勒成像（ 图2B）捕获。成功TAC将导致下游的显著增加流速缩颈站点（TAC小鼠通常〜4米/秒）。横跨收缩压力梯度是基于峰值流速计算，根据修改后的伯努利方程（ 图2C）。 图3 </stroNG&gt;显示假（ 图3A）或TAC心脏（ 图3B）的胸骨旁长轴观的B和M模式下的图像。上面板显示左心室，室间隔，并从假或TAC小鼠右心室的部分的B模式图像。下面板显示从假或TAC小鼠几个心动周期的M型描。心脏的尺寸的测量显示，包括左心室前壁的厚度（LVAW），左心室内径（LVID），在舒张和收缩左心室后壁厚度（LVPW）。注意遭受TAC与假手术相比小鼠心脏显著增加壁厚。 图4示出假（ 图4A）或TAC心脏（ 图4B）的胸骨旁短轴视图图像。每个面板的上部分示出了M模式轴（多特编线）放置在左心室的中心。每个面板的下部是M-模式与表示上述心肌的尺寸线跟踪。作为肥大的标志物，心室和可以精确地确定间隔壁厚。经过TAC小鼠表现出增加壁厚由LVAWd和LVPWD所评估的评估，LVISd和LVISs脑室扩大，由LVFS及LVEF的评估收缩力下降，并增加LV质量（ 图5）。 图6显示二尖瓣流模式（ 图6C，D）B型心尖四腔心切面（ 图6A，B）和PW多普勒图像。 E峰和A速度，IVCT，IVRT和ET的测量显示。在E / A比值和MPI计算（ 图6E - I）。一个健康的小鼠心脏有一个E / A比值≥1和MPI值≤0.5。在直径病理情况斯托利奇或收缩的心脏功能障碍，例如在经受交，降低的E / A比和/或增加的MPI值的小鼠通常观察到。 <img alt="图1" src="/files/ftp_upload/54101/54101fig1.jpg" /> 图1.受假手术（A）或TAC（B）小鼠心脏的主动脉弓观的B模式图像。主要的主动脉分支，包括无名动脉（IA），左颈总动脉（LCCA）和左锁骨下动脉（LSA）被示出。需要注意的是横向主动脉缩窄（白色箭头指示）可在TAC可视化而不是假心脏。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54101/54101fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图2" src="/files/ftp_upload/54101/54101fig2.jpg" /> 在Transve图2.颜色/ PW多普勒超声RSE从主动脉弓查看。颜色（A）和假和TAC心中PW（B）多普勒图像主动脉血FOW所示。从脉冲多普勒成像获得峰主动脉速度被用于根据修改后的伯努利方程（C）的计算压力梯度。这些数据证实了成功的TAC手术〜70毫米汞柱的压力梯度。 * p &lt;0.05 与 。假。数据表示为平均值±SEM，N = 15深水和n = 13 TAC。学生t检验来确定统计学意义。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54101/54101fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图3" src="/files/ftp_upload/54101/54101fig3.jpg" /> 图3.胸骨旁长轴（PLAX）小鼠心脏观受到假手术（A）或TAC（B）。 </strong&gt; M型图像显示，该样品的体积（虚线黄线在上图）和舒张和收缩（蓝线在较低的面板）的心脏尺寸测量的位置。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54101/54101fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图4" src="/files/ftp_upload/54101/54101fig4.jpg" /> 小鼠心脏图4.胸骨旁短轴（PSAX）查看遭受假手术（A）或TAC（B）M型图像显示，该样品体积的位置（虚线黄线在上图）和心脏测量尺寸在舒张和收缩（蓝线中的下图）。星号表示乳头肌。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54101/54101fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 图5.心脏形态和功能的变化继 如图4进行短轴TAC，M型成像超声心动图评价 。（A）LVAWd，舒张期左室前壁的厚度。 （B）LVPWD，留在舒张期左室后壁厚度。 （C）的LVIDD，留在舒张心室内部直径。 （D）的LVIDs，收缩期左室内径。 （E）LVFS，左室短轴缩短率。 LVFS（％）=（LVIDD-LVIDs）/ LVIDD×100％。 （F）LVEF，左室射血分数。射血分数（％）=（LVEDV-LVESV）/ LVEDV×100％。 LVEDV和LVESV表示左室舒张末期和收缩末期容积分别。吕量和射血分数精确由Simpso评估<html> N为方法。左心室容积由嵌合众多磁盘估计入脑室:辛普森体积= [区（1）+区域（2）+ ...区域（N）]×长度。辛普森面积和长度被跟踪的LV心内膜边界在长轴和短轴视图获得。 （G），LV（左心室）的质量。 LV质量（毫克）= 1.05×[（LVIDD + LVPWD + IVSD）3 - （LVIDD）3]。因子1.05表示心肌的特定密度。 （H）的&#160; HR，心脏率。 * p &lt;0.05 与 。假。分析小鼠的数目示于每个面板的条。数据表示为平均值±标准差学生t检验来确定统计学意义。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54101/54101fig5large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> p_upload / 54101 / 54101fig6.jpg"/&gt; 图6.二尖瓣血流多普勒显像（A和B）假（A）的B-模式心尖四腔心切或TAC（B）心脏评估 。 LV，左心室; RV，右心室; MV，二尖瓣;电视，三尖瓣; LA，左心房; RA，右心房。 &#160; （C和D）假（C）或TAC（D）心脏跨二尖瓣血流脉冲多普勒波形。相关的测量被示出。 （E），E / A，E峰和A速比。 （F）IVCT，等容收缩期时间。 （G）IVRT，等容舒张时间。 （H）ET，射血时间。 （I）MPI，心肌的性能指标。 * p &lt;0.05 与 。假。分析小鼠的数目示于每个面板的条。数据表示为平均值77; SEM学生t检验来确定统计学意义。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54101/54101fig6large.jpg" target="_blank">请点击此处查看该图的放大版本。</a>

Watch this Scientific Journal Video about Assessment of Cardiac Morphological and Functional Changes in Mouse Model of Transverse Aortic Constriction by Echocardiographic Imaging at JoVE.com

Assessment of Cardiac Morphological and Functional Changes in Mouse Model of Transverse Aortic Constriction by Echocardiographic Imaging

此协议的目的是通过横向主动脉缩窄创建心脏疾病的小鼠模型评估无创心脏结构和功能改变，采用B和M型超声心动图和彩色/脉冲多普勒成像。

在横向主动脉缩窄的小鼠模型和心脏形态学评估功能改变通过超声心动图成像

Transverse aortic constriction (TAC) in mice has been used as a valuable model to study mechanisms of cardiac hypertrophy and heart failure1. A reliable ...

assessment-cardiac-morphological-functional-changes-mouse-model

Nanyang Technological University

Research

JoVE Journal

Medicine

18.1K 次观看.  University of Washington. 此协议的目的是通过横向主动脉缩窄创建心脏疾病的小鼠模型评估无创心脏结构和功能改变，采用B和M型超声心动图和彩色/脉冲多普勒成像。 

视频: Assessment of Cardiac Morphological and Functional Changes in Mouse Model of Transverse Aortic Constriction by Echocardiographic Imaging

Echocardiographic Assessment of the Right Heart in Mice

Transgenic and toxic models of pulmonary arterial hypertension (PAH) are widely used to study the pathophysiology of PAH and to investigate potential therapies. Given the expense and time involved in creating animal models of disease, it is critical that researchers have tools to accurately assess phenotypic expression of disease. Right ventricular dysfunction is the major manifestation of pulmonary hypertension. Echocardiography is the mainstay of the noninvasive assessment of right ventricular function in rodent models and has the advantage of clear translation to humans in whom the same tool is used. Published echocardiography protocols in murine models of PAH are lacking.
In this article, we describe a protocol for assessing RV and pulmonary vascular function in a mouse model of PAH with a dominant negative BMPRII mutation; however, this protocol is applicable to any diseases affecting the pulmonary vasculature or right heart. We provide a detailed description of animal preparation, image acquisition and hemodynamic calculation of stroke volume, cardiac output and an estimate of pulmonary artery pressure.

This article provides a protocol for the echocardiographic assessment of right ventricular size and pulmonary hypertension in mice. Applications include phenotype determination and serial assessment in transgenic and toxin-induced mouse models of cardiomyopathy and pulmonary vascular disease.

右心小鼠的超声心动图评价

Transgenic and toxic models of pulmonary arterial hypertension (PAH) are widely used to study the pathophysiology of PAH and to investigate potential ...

科研

医学

Ascending Aortic Constriction in Rats for Creation of Pressure Overload Cardiac Hypertrophy Model

Ascending aortic constriction is the most common and successful surgical model for creating pressure overload induced cardiac hypertrophy and heart failure. Here, we describe a detailed surgical procedure for creating pressure overload and cardiac hypertrophy in rats by constriction of the ascending aorta using a small metallic clip. After anesthesia, the trachea is intubated by inserting a cannula through a half way incision made between two cartilage rings of trachea. Then a skin incision is made at the level of the second intercostal space on the left chest wall and muscle layers are cleared to locate the ascending portion of aorta. The ascending aorta is constricted to 50&#8211;60% of its original diameter by application of a small sized titanium clip. Following aortic constriction, the second and third ribs are approximated with prolene sutures. The tracheal cannula is removed once spontaneous breathing was re-established. The animal is allowed to recover on the heating pad by gradually lowering anesthesia. The intensity of pressure overload created by constriction of the ascending aorta is determined by recording the pressure gradient using trans-thoracic two dimensional Doppler-echocardiography. Overall this protocol is useful to study the remodeling events and contractile properties of the heart during the gradual onset and progression from compensated cardiac hypertrophy to heart failure stage.

We describe a stepwise procedure for creating pressure overload and left ventricular hypertrophy in Wistar rats by constriction of the ascending aorta using a small metallic clip. This model is extensively used for studying remodeling changes during cardiac hypertrophy and for identifying and evaluating strategies for regression of such changes.

大鼠建立压力超负荷心肌肥厚模型在升主动脉缩窄

Ascending aortic constriction is the most common and successful surgical model for creating pressure overload induced cardiac hypertrophy and heart ...

Assessment of Right Ventricular Structure and Function in Mouse Model of Pulmonary Artery Constriction by Transthoracic Echocardiography

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, the RV is significantly affected in pulmonary diseases such as pulmonary artery hypertension (PAH). In addition, the RV is remarkably sensitive to cardiac pathologies, including left ventricular (LV) dysfunction, valvular disease or RV infarction4. To understand the role of RV in the pathogenesis of cardiac diseases, a reliable and noninvasive method to access the RV structurally and functionally is essential.
A noninvasive trans-thoracic echocardiography (TTE) based methodology was established and validated for monitoring dynamic changes in RV structure and function in adult mice. To impose RV stress, we employed a surgical model of pulmonary artery constriction (PAC) and measured the RV response over a 7-day period using a high-frequency ultrasound microimaging system. Sham operated mice were used as controls. Images were acquired in lightly anesthetized mice at baseline (before surgery), day 0 (immediately post-surgery), day 3, and day 7 (post-surgery). Data was analyzed offline using software.
Several acoustic windows (B, M, and Color Doppler modes), which can be consistently obtained in mice, allowed for reliable and reproducible measurement of RV structure (including RV wall thickness, end-diastolic&#160;and end-systolic dimensions), and function (fractional area change, fractional shortening, PA peak velocity, and peak pressure gradient) in normal mice and following PAC.
Using this method, the pressure-gradient resulting from PAC was accurately measured in real-time using Color Doppler mode and was comparable to direct pressure measurements performed with a Millar high-fidelity microtip catheter. Taken together, these data demonstrate that RV measurements obtained from various complimentary views using echocardiography are reliable, reproducible and can provide insights regarding RV structure and function. This method will enable a better understanding of the role of RV cardiac dysfunction.

Right ventricle (RV) dysfunction is critical to the pathogenesis of cardiovascular disease, yet limited methodologies are available for its evaluation. Recent advances in ultrasound imaging provide a noninvasive and accurate option for longitudinal RV study. Herein, we detail a step-by-step echocardiographic method using a murine model of RV pressure overload.

右心室结构和功能的肺动脉缩窄经胸超声小鼠模型的评估

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, ...

Noninvasive Assessment of Cardiac Abnormalities in Experimental Autoimmune Myocarditis by Magnetic Resonance Microscopy Imaging in the Mouse

Myocarditis is an inflammation of the myocardium, but only ~10% of those affected show clinical manifestations of the disease. To study the immune events of myocardial injuries, various mouse models of myocarditis have been widely used. This study involved experimental autoimmune myocarditis (EAM) induced with cardiac myosin heavy chain (Myhc)-&#945; 334-352 in A/J mice; the affected animals develop lymphocytic myocarditis but with no apparent clinical signs. In this model, the utility of magnetic resonance microscopy (MRM) as a non-invasive modality to determine the cardiac structural and functional changes in animals immunized with Myhc-&#945; 334-352 is shown. EAM and healthy mice were imaged using a 9.4 T (400 MHz) 89 mm vertical core bore scanner equipped with a 4 cm millipede radio-frequency imaging probe and 100 G/cm triple axis gradients. Cardiac images were acquired from anesthetized animals using a gradient-echo-based cine pulse sequence, and the animals were monitored by respiration and pulse oximetry. The analysis revealed an increase in the thickness of the ventricular wall in EAM mice, with a corresponding decrease in the interior diameter of ventricles, when compared with healthy mice. The data suggest that morphological and functional changes in the inflamed hearts can be non-invasively monitored by MRM in live animals. In conclusion, MRM offers an advantage of assessing the progression and regression of myocardial injuries in diseases caused by infectious agents, as well as response to therapies.

This study demonstrates the successful establishment of magnetic resonance microscopy imaging as a non-invasive tool to assess the cardiac abnormalities in mice affected with autoimmune myocarditis. The data indicate that the technique can be used to monitor the disease-progression in live animals.

心脏异常的实验性自身免疫性心肌炎的无创性评估磁共振成像显微镜在鼠标

Myocarditis is an inflammation of the myocardium, but only ~10% of those affected show clinical manifestations of the disease. To study the immune events ...

A Model of Cardiac Remodeling Through Constriction of the Abdominal Aorta in Rats

Heart failure is one of the leading causes of death worldwide. It is a complex clinical syndromethat includes fatigue, dyspnea, exercise intolerance, and fluid retention. Changes in myocardial structure, electrical conduction, and energy metabolism develop with heart failure, leading to contractile dysfunction, increased risk of arrhythmias, and sudden death. Hypertensive heart disease is one of the key contributing factors of cardiac remodeling associated with heart failure. The most commonly-used animal model mimicking hypertensive heart disease is created via surgical interventions, such as by narrowing the aorta. Abdominal aortic constriction is a useful experimental technique to induce a pressure overload, which leads to heart failure. The surgery can be easily performed, without the need for chest opening or mechanical ventilation. Abdominal aortic constriction-induced cardiac pathology progresses gradually, making this model relevant to clinical hypertensive heart failure. Cardiac injury and remodeling can be observed 10 weeks after the surgery. The method described here provides a simple and effective approach to produce a hypertensive heart disease animal model that is suitable for studying disease mechanisms and for testing novel therapeutics.

A rat model of abdominal aortic constriction that induces cardiac hypertrophy and remodeling is described. An efficient, highly-reproducible, and minimally-invasive method is used to provide a simple yet useful platform for research in myocardial hypertrophy and dysfunction.

心脏重构通过大鼠腹主动脉缩窄的模型

Heart failure is one of the leading causes of death worldwide. It is a complex clinical syndromethat includes fatigue, dyspnea, exercise intolerance, and ...

Minimally Invasive Transverse Aortic Constriction in Mice

Minimally invasive transverse aortic constriction (MTAC) is a more desirable method for the constriction of the transverse aorta in mice than standard open-chest transverse aortic constriction (TAC). Although transverse aortic constriction is a highly functional method for the induction of high pressure in the left ventricle, it is a more difficult and lengthy procedure due to its use of artificial ventilation with tracheal intubation. TAC is oftentimes also less survivable, as the newer method, MTAC, neither requires the cutting of the ribs and intercostal muscles nor tracheal intubation with a ventilation setup. In MTAC, as opposed to a thoracotomy to access to the chest cavity, the aortic arch is reached through a midline incision in the anterior neck. The thyroid is pulled back to reveal the sternal notch. The sternum is subsequently cut down to the second rib level, and the aortic arch is reached simply by separating the connective tissues and thymus. From there, a suture can be wrapped around the arch and tied with a spacer, and then the sternal cut and skin can be closed. MTAC is a much faster and less invasive way to induce left ventricular hypertension and enables the possibility for high-throughput studies. The success of the constriction can be verified using high-frequency trans-thoracic echocardiography, particularly color Doppler and pulsed-wave Doppler, to determine the flow velocities of the aortic arch and left and right carotid arteries, the dimension of the blood vessels, and the left ventricular function and morphology. A successful constriction will also trigger significant histopathological changes, such as cardiac muscle cell hypertrophy with interstitial and perivascular fibrosis. Here, the procedure of MTAC is described, demonstrating how the resulting flow changes in the carotid arteries can be examined with echocardiography, gross morphology, and histopathological changes in the heart.

Minimally invasive transverse aortic constriction (MTAC) conserves the essentials of regular transverse aortic constriction (TAC) while eliminating the use of a ventilator with tracheal intubation. It proves to be a highly desirable method for high-throughput studies on left ventricular overload, particularly in translational studies.

微创横向主动脉缩窄小鼠

Minimally invasive transverse aortic constriction (MTAC) is a more desirable method for the constriction of the transverse aorta in mice than standard ...

Echocardiographic and Histological Examination of Cardiac Morphology in the Mouse

An increasing number of genetically modified mouse models has become available in recent years. Moreover, the number of pharmacological studies performed in mice is high. Phenotypic characterization of these mouse models also requires the examination of cardiac function and morphology. Echocardiography and magnetic resonance imaging (MRI) are commonly used approaches to characterize cardiac function and morphology in mice. Echocardiographic and MRI equipment specialized for use in small rodents is&#160;expensive and requires a dedicated space. This protocol describes cardiac measurements in mice using a clinical echocardiographic system with a 15 MHz human vascular probe. Measurements are performed on anesthetized adult mice. At least three image sequences are recorded and analyzed for each animal in M-mode in the parasternal short-axis view. Afterwards, cardiac histological examination is performed, and cardiomyocyte diameters are determined on hematoxylin-eosin- or wheat germ agglutinin (WGA)-stained paraffin sections. Vessel density is determined morphometrically after Pecam-1 immunostaining. The protocol has been applied successfully to pharmacological studies and different genetic animal models under baseline conditions, as well as after experimental myocardial infarction by the permanent ligation of the left anterior descending coronary artery (LAD). In our experience, echocardiographic investigation is limited to anesthetized animals and is feasible in adult mice weighing at least 25 g.

Echocardiographic examination is frequently used in mice. Expensive high-resolution ultrasound devices have been developed for this purpose. This protocol describes an affordable echocardiographic procedure combined with histological morphometric analyses to determine cardiac morphology.

超声心动图与小鼠心脏形态学的组织学检查

An increasing number of genetically modified mouse models has become available in recent years. Moreover, the number of pharmacological studies performed ...

Technique of Minimally Invasive Transverse Aortic Constriction in Mice for Induction of Left Ventricular Hypertrophy

Transverse aortic constriction (TAC) in mice is one of the most commonly used surgical techniques for experimental investigation of pressure overload-induced left ventricular hypertrophy (LVH) and its progression to heart failure. In the majority of the reported investigations, this procedure is performed with intubation and ventilation of the animal which renders it demanding and time-consuming and adds to the surgical burden to the animal. The aim of this protocol is to describe a simplified technique of minimally invasive TAC without intubation and ventilation of mice. Critical steps of the technique are emphasized in order to achieve low mortality and high efficiency in inducing LVH.
Male C57BL/6 mice (10-week-old, 25-30 g, n=60) were anesthetized with a single intraperitoneal injection of a mixture of ketamine and xylazine. In a spontaneously breathing animal following a 3-4 mm upper partial sternotomy, a segment of 6/0 silk suture threaded through the eye of a ligation aid was passed under the aortic arch and tied over a blunted 27-gauge needle. Sham-operated animals underwent the same surgical preparation but without aortic constriction. The efficacy of the procedure in inducing LVH is attested by a significant increase in the heart/body weight ratio. This ratio is obtained at days 3, 7, 14 and 28 after surgery (n = 6 - 10 in each group and each time point). Using our technique, LVH is observed in TAC compared to sham animals from day 7 through day 28. Operative and late (over 28 days) mortalities are both very low at 1.7%.
In conclusion, our cost-effective technique of minimally invasive TAC in mice carries very low operative and post-operative mortalities and is highly efficient in inducing LVH. It simplifies the operative procedure and reduces the strain put on the animal. It can be easily performed by following the critical steps described in this protocol.

The aim of this protocol is to describe step-by-step the technique of minimally invasive transverse aortic constriction (TAC) in mice. By elimination of intubation and ventilation which are mandatory for the commonly used standard procedure, minimally invasive TAC simplifies the operative procedure and reduces the strain put on the animal.

小鼠横主动脉狭窄诱导左心室肥厚的技术研究

Transverse aortic constriction (TAC) in mice is one of the most commonly used surgical techniques for experimental investigation of pressure ...

A Closed-chest Model to Induce Transverse Aortic Constriction in Mice

Research on cardiac hypertrophy and heart failure is frequently based on pressure overload mouse models induced by TAC. The standard procedure is to perform a partial thoracotomy to visualize the transverse aortic arch. However, the surgical trauma caused by the thoracotomy in open-chest models changes the respiratory physiology as the ribs are dissected and left unattached after chest closure. To prevent this, we established a minimally invasive, closed chest approach via lateral thoracotomy. Herein we approach the aortic arch via the 2nd intercostal space without entering the chest cavities, leaving the mouse with a less traumatic injury to recover from. We perform this operation using standard laboratory settings for open chest TAC procedures with equal survival rates. Apart from maintaining physiological breathing patterns due to the closed chest approach, the mice seem to benefit by showing rapid recovery, as the less invasive technique appears to facilitate a fast healing process and to reduce immune response after trauma.

Here, we present a protocol of Transverse Aortic constriction (TAC) via a lateral thoracotomy. This technique is a minimally invasive, closed chest surgical procedure aiming to simulate pressure overload and heart failure in mice utilizing standard TAC laboratory settings.

诱导小鼠横向主动脉狭窄的闭合胸模型

Research on cardiac hypertrophy and heart failure is frequently based on pressure overload mouse models induced by TAC. The standard procedure is to ...

Echocardiographic Assessment of Cardiac Anatomy and Function in Adult Rats

The use of experimental animal models has become crucial in cardiovascular science. Most studies using rodent models are focused on two-dimensional imaging to study the cardiac anatomy of the left ventricle and M-mode echo to assess its dimensions. However, this could limit a comprehensive study. Herein, we describe a protocol that allows an assessment of the heart chamber size, left ventricular function (systolic and diastolic) and valvular function. A conventional medical ultrasound machine was used in this protocol and different echo views were obtained through left parasternal, apical and suprasternal windows. In the left parasternal window, the long and short axis were acquired to analyze left chamber dimensions, right ventricle and pulmonary artery dimensions, and mitral, pulmonary and aortic valve function. The apical window allows the measurement of heart chamber dimensions and evaluation of systolic and diastolic parameters. It also allows Doppler assessment with detection and quantification of heart valve disturbances (regurgitation or stenosis). Different segments and walls of the left ventricle are visualized throughout all views. Finally, the ascending aorta, aortic arch, and descending aorta can be imaged through the suprasternal window. A combination of ultrasound imaging, Doppler flow and tissue Doppler assessment have been obtained to study cardiac morphology and function. This represents an important contribution to improve the assessment of cardiac function in adult rats with impact for research using these animal models.

A non-invasive protocol for transthoracic echocardiography assessment of cardiac anatomy and function for adult rats is presented in the current study. The heart valves, all four cardiac chambers and the ascending aorta, aortic arch and descending aorta are studied in detail.

成人大鼠心脏解剖与功能的超声心动图评估

The use of experimental animal models has become crucial in cardiovascular science. Most studies using rodent models are focused on two-dimensional ...