我们要感谢在香港理工大学生命科学（ULS）大学的研究设施，以提供VEVO 2100超声系统。特别感谢温家宝纯一博士从生物医学工程，香港理工大学，跨学科司提供训练和便利。这项工作是由香港政府拨款计划GRF 17127215，764812和HKU6 / CRF / 11G比利KC周的支持。

该协议遵循了委员会对教学与研究（CULATR）使用活的动物在香港大学的指导方针。 1.操作场地准备<ol><li>消毒用75％异丙醇的手术部位。调节加热垫温度至37℃，以避免在心脏和变化受试动物的呼吸率。 </li><li>使用在重力位移消毒灭菌的外科器械在121℃进行30分钟，或通过其它适当的方法。 </li><li>取2 - 4 30号针头和针保持器曲线它们，如在图1看到的那样，以使对结扎和组织分离并用作牵开器的工具。安装在一个棉花施用器用于在外科手术中使用的现弯曲针。 </li><li>钝的27号针和曲线它与针保持器90º。通过摩擦硬表面，使在连接步骤0.4毫米间隔平滑小费。 </li></ol><ol><li>麻醉2月龄，雄性，22-25克的C57BL / 6N小鼠相对于体重的适当氯胺酮和赛拉嗪的混合物:100毫克/公斤+10毫克/公斤的ip确认带负尾捏反射的麻醉。 </li><li>用脱毛霜2至3分钟应用程序中删除的前颈部和胸部的头发。取出用温水和棉签的精华。 </li><li>应用眼用软膏或凝胶的动物的眼睛来防止晒出角膜。 </li><li>放置在一个加热垫的动物仰卧位，并进行术中监测，是一定要保持适当的文件在每15分钟间隔。 </li><li>使用外科纸带固定四肢到加热垫，以保持在正确的位置的动物的手术过程中。 </li><li>用酒精和聚维酮碘溶液三次交替消毒皮肤。 </li><li>使用无菌博士猿带有裸操作字段，以防止污染。使用新的无菌手套对每个鼠标和必要的。 </li></ol> 3.连接程序<ol><li>在颈部和胸部用手术刀的中线位置打开小鼠的皮肤上。 </li><li>轻轻用钝的剪刀分离结缔组织拉向头甲状腺。 </li><li>在向两侧与弯曲针的中线分开的气管肌肉层。 </li><li>使用钝剪，胸骨的第二肋（大约5毫米）。打开用拉钩或弯钳切。 </li><li>彼此并通过分离与弯曲针结缔组织下部胸壁分开胸腺裂片;横向主动脉弓和两个颈动脉将在这一点上清晰可见。 </li><li>放置弓下弯针和由脓另一侧的血管壁和结缔组织之间穿孔兴弯曲探出头来。 </li><li>使用弯针，拉主动脉弓下6-0单丝缝合。 </li><li>放置在循环中的隔离件和具有双结固定到位缝线。轻轻取下垫片。 </li><li>确认结位置成功收缩并切断缝线的末端。 </li><li>关闭使用6/0丝线缝合胸壁用一个简单的间断缝合模式。关闭了6/0单丝缝合皮肤在连续缝合模式。 </li></ol> 4.术后护理<ol><li>应用聚维酮碘溶液到缝合部位，然后将动物在回收和手术后监测预热笼。 </li><li>注射丁丙诺啡（0.05 - 0.1毫克/千克SC每12小时）后，动物已经苏醒，以减轻疼痛，并提供适当的软食鼠标。 </li><li>返回该动物完全恢复之后的12小时光照/黑暗周期的房间。 </li></ol> 5。超声心动图:结扎成功和测量确认<ol><li>一周后，麻醉先前带状小鼠用3 - 5％异氟醚，感应，和1 - 1.5％，以进行维护，以1升/分钟氧气流速。 </li><li>删除使用脱毛霜的胸毛。彻底去除，用温水和棉签的精华。 </li><li>固定鼠标在仰卧位置向动物处理平台，保持在37℃。应用电极凝胶的爪子和磁带他们用电极垫。 </li><li>应用超声波凝胶鼠标胸前。带有40兆赫MS550D探针和高频超声波系统，在左，右颈动脉进行彩色多普勒和脉冲波多普勒扫描，以及在主动脉弓。 </li><li>使用B模式，找到左心室。使用M模式中，收缩和舒张的壁厚可以被测量。利用电影存储和帧存储根据需要保存的数据和图像。 </li><li> ü唱B型，定位分支点之前的左颈动脉。利用脉冲波和彩色多普勒评估流程。与类似观点的右颈总动脉重复。保存电影存储和帧存储模式的图像供以后分析。 </li><li>倾斜动物处理平台到最左边，使鼠标在左侧卧位。把探头上的鼠标，30°在胸骨旁位置从平行于头的位置偏移，和操纵的X和Y找到主动脉弓。 </li><li>找到收缩。使用彩色多普勒模式以使收缩更明显的部位，如将要流过点之间的狭窄通道血液其中两个颈动脉从主动脉弓分支出来。 </li><li>利用脉冲波和彩色多普勒测量峰值流速。利用电影存储和帧存储根据需要保存的数据和图像。 </li><li>让动物在俯卧位加热垫恢复。返回动物到原始笼中，12小时光照/黑暗周期的房间后它已经完全从麻醉中恢复。 </li></ol>

<ol><li>Rockman, H. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Segregation+of+atrial-specific+and+inducible+expression+of+an+atrial+natriuretic+factor+transgene+in+an+in+vivo+murine+model+of+cardiac+hypertrophy%5BTitle%5D)+AND+%22Proc+Natl+Acad+Sci+U+S+A%22%5BJournal%5D)">Segregation of atrial-specific and inducible expression of an atrial natriuretic factor transgene in an in vivo murine model of cardiac hypertrophy.</a> Proc Natl Acad Sci U S A. 88 (18), 8277-8281 (1991).</li>
<li>de Almeida, A. C., van Oort, R. J., Wehrens, X. H. <a target="_blank" href="https://www.ncbi.nlm.nih.gov/pubmed/20410870">Transverse aortic constriction in mice.</a> J Vis Exp. (38), (2010).</li>
<li>Hu, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Minimally+invasive+aortic+banding+in+mice%3A+effects+of+altered+cardiomyocyte+insulin+signaling+during+pressure+overload%5BTitle%5D)+AND+%22Am+J+Physiol+Heart+Circ+Physiol%22%5BJournal%5D)">Minimally invasive aortic banding in mice: effects of altered cardiomyocyte insulin signaling during pressure overload.</a> Am J Physiol Heart Circ Physiol. 285 (3), H1261-H1269 (2003).</li>
<li>Shimizu, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Excessive+cardiac+insulin+signaling+exacerbates+systolic+dysfunction+induced+by+pressure+overload+in+rodents%5BTitle%5D)+AND+%22J+Clin+Invest%22%5BJournal%5D)">Excessive cardiac insulin signaling exacerbates systolic dysfunction induced by pressure overload in rodents.</a> J Clin Invest. 120 (5), 1506-1514 (2010).</li>
<li>Tarnavski, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Mouse+surgical+models+in+cardiovascular+research%5BTitle%5D)+AND+%22Methods+Mol+Biol%22%5BJournal%5D)">Mouse surgical models in cardiovascular research.</a> Methods Mol Biol. 573, 115-137 (2009).</li>
<li>Zhang, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+modified+murine+model+for+the+study+of+reverse+cardiac+remodelling%5BTitle%5D)+AND+%22Exp+Clin+Cardiol%22%5BJournal%5D)">A modified murine model for the study of reverse cardiac remodelling.</a> Exp Clin Cardiol. 18 (2), e115-e117 (2013).</li>
<li>Hartley, C. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Doppler+estimation+of+reduced+coronary+flow+reserve+in+mice+with+pressure+overload+cardiac+hypertrophy%5BTitle%5D)+AND+%22Ultrasound+Med+Biol%22%5BJournal%5D)">Doppler estimation of reduced coronary flow reserve in mice with pressure overload cardiac hypertrophy.</a> Ultrasound Med Biol. 34 (6), 892-901 (2008).</li>
<li>Scherrer-Crosbie, M., Thibault, H. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Echocardiography+in+translational+research%3A+of+mice+and+men%5BTitle%5D)+AND+%22J+Am+Soc+Echocardiogr%22%5BJournal%5D)">Echocardiography in translational research: of mice and men.</a> J Am Soc Echocardiogr. 21 (10), 1083-1092 (2008).</li>
<li>Faerber, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Induction+of+heart+failure+by+minimally+invasive+aortic+constriction+in+mice%3A+reduced+peroxisome+proliferator-activated+receptor+gamma+coactivator+levels+and+mitochondrial+dysfunction%5BTitle%5D)+AND+%22J+Thorac+Cardiovasc+Surg%22%5BJournal%5D)">Induction of heart failure by minimally invasive aortic constriction in mice: reduced peroxisome proliferator-activated receptor gamma coactivator levels and mitochondrial dysfunction.</a> J Thorac Cardiovasc Surg. 141 (2), 492-500 (2011).</li>
<li>Li, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Assessment+of+Cardiac+Morphological+and+Functional+Changes+in+Mouse+Model+of+Transverse+Aortic+Constriction+by+Echocardiographic+Imaging%5BTitle%5D)+AND+%22J+Vis+Exp%22%5BJournal%5D)">Assessment of Cardiac Morphological and Functional Changes in Mouse Model of Transverse Aortic Constriction by Echocardiographic Imaging.</a> J Vis Exp. (112), (2016).</li>
</ol>

The authors declare that they have no competing financial interests.

洛克人和同事发明了第一个方法主动脉缩窄为学习压力超负荷的心脏的方法。这使研究开始揭露高血压和心脏衰竭1的细胞和分子的后果。一种改进的方法，微创横向主动脉缩窄（MTAC），提供了左心室压力负荷和心脏衰竭的诱导的顺从，依赖于时间的方法，没有以往的横向主动脉缩窄9的缺点。该过程本身可以比TAC被显著更容易且具有增加的存活率进行。该方法?...

<html>这篇文章的总体目标是演示如何横向小鼠主动脉缩窄（TAC）可以被修改以产生一个更简单，更方便的手术。 TAC最早在1991年1引入并启用分子生物学家研究导致肥大在左心室和心脏衰竭，特别是在小动物与操纵基因组2，3，4，5，6中的细胞和分子通路。尽管它在产生所需的压力超负荷功效，该技术最终由难以执行的程序和由它的低存活率的限制。一位外科医生在进行TAC必须能够执行气管插管，开胸，为了防止肺萎陷1使用人工通气。 内容"&gt;通常，一个简单的和更小侵入性方法是期望的。因此，微创横向主动脉缩窄（MTAC）被制定3，虽然结果（具体地说，左心室肥大）是一样的，该过程涉及显著较少装置和向动物损伤较小。MTAC证明是具有更大的生存率，90％以上，理想的方法，并且具有唯一的15至25分钟。成功的手术后死亡的罕见情况下的操作时间可以归因于太主动脉弓-tight收缩，造成了巨大的左心室超负荷和致命减少血液供应的关键器官如肾脏。 在这个步骤完成后，超声心动图可以用来评估带和心脏形态和功能的成功。的高频超声波系统可被用于测量直径，并在左，右流的变化颈动脉，以显现主动脉弓缩窄为峰值流速的测量，并确定左心室壁的厚度和功能参数7,8。安乐死后，器官也可以收集对用苏木精和曙红染色和天狼猩红胶原染色的组织病理学研究，后者为纤维化的观测是特别有用的。

<table><tbody><tr><td>&lt;strong&gt;1 inch 30 Gauge Needles&lt;/strong&gt;</td><td>BD, Franklin Lakes, NJ 07417, USA.&amp;nbsp;</td><td>305128</td><td>Curved as in the procedure and &lt;strong&gt;Figure 1&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;27 Gauge Needle&lt;/strong&gt;</td><td>BD, Franklin Lakes, NJ 07417, USA.&amp;nbsp;</td><td>301629</td><td>Make blunt and smooth for spacer</td></tr><tr><td>&lt;strong&gt;6/0 Dafilon&lt;/strong&gt;</td><td>B. Braun, 34212 Melsungen, Hessen, Germany.</td><td>C0933066</td><td></td></tr><tr><td>&lt;strong&gt;6/0 Silkam&lt;/strong&gt;</td><td>B. Braun, 34212 Melsungen, Hessen, Germany.</td><td>C0762067</td><td></td></tr><tr><td>&lt;strong&gt;Sterile gloves&lt;/strong&gt;</td><td>A.R. Medicom, Inc (Asia), Hong Kong.</td><td></td><td></td></tr><tr><td>&lt;strong&gt;Cotton Applicator&lt;/strong&gt;</td><td>Mannings, Quarry Bay, Hong Kong.</td><td></td><td>Local Shopping Center</td></tr><tr><td>&lt;strong&gt;Depilatory Cream&lt;/strong&gt;</td><td>Veet (Hong Kong), Kwun Tong, Kowloon, Hong Kong</td><td></td><td>Local Shopping Center</td></tr><tr><td>&lt;strong&gt;Lexer-Baby Scissor&lt;/strong&gt;</td><td>FST, British Columbia V7H 0A6, Canada.</td><td>14078-10</td><td></td></tr><tr><td>&lt;strong&gt;Curved Iris Forcep&lt;/strong&gt;</td><td>FST, British Columbia V7H 0A6, Canada.</td><td>11065-07</td><td></td></tr><tr><td>&lt;strong&gt;Micro Olsen-Hegar Needle Holder&lt;/strong&gt;</td><td>WPI, Sarasota, FL 34240, USA.&amp;nbsp;</td><td>501989</td><td></td></tr><tr><td>&lt;strong&gt;Stereo Micrioscope&lt;/strong&gt;</td><td>WPI, Sarasota, FL 34240, USA.&amp;nbsp;</td><td>PZMIII-BS</td><td></td></tr><tr><td>&lt;strong&gt;GenTeal Eye Gel&lt;/strong&gt;</td><td>Novartis, East Hanover, NJ 07936, USA.&amp;nbsp;</td><td></td><td>Local Pharmacy</td></tr><tr><td>&lt;strong&gt;Heating Pad&lt;/strong&gt;</td><td>Kent Scientific Corporation, Torrington, CT 06790, USA.&amp;nbsp;</td><td>DCT-20</td><td></td></tr><tr><td>&lt;strong&gt;Surgical tape&lt;/strong&gt;</td><td>Laboratory Animal Unit</td><td></td><td></td></tr><tr><td>&lt;strong&gt;Ketamine and Xylazine&lt;/strong&gt;</td><td>Laboratory Animal Unit</td><td></td><td></td></tr><tr><td>&lt;strong&gt;Betadine&lt;/strong&gt;</td><td>Laboratory Animal Unit</td><td></td><td></td></tr><tr><td>&lt;strong&gt;Buprenorphine&lt;/strong&gt;</td><td>Laboratory Animal Unit</td><td></td><td></td></tr></tbody></table>

minimally invasive transverse aortic constriction in mice

微创横向主动脉缩窄（MTAC）为横向主动脉的小鼠比标准开胸横向主动脉缩窄（TAC）缩颈更理想的方法。虽然横向主动脉缩窄为左心室高压的感应一个高功能的方法，它是一个更加困难和冗长过程由于其使用人工通气的气管插管。 TAC是常常也少生存，作为较新的方法，MTAC，既不要求肋骨和肋间肌也没有气管插管与通气设置切割。在MTAC，相对于一个开胸访问到胸腔，通过设在前壁颈部正中切口到达主动脉弓。甲状腺拉回以显示胸骨切迹。胸骨随后降低到第二肋水平，并通过分离的结缔组织和胸腺到达主动脉弓简单。从还有，缝合线能够围绕拱形缠绕并与间隔并列，然后胸骨切口和皮肤可以关闭。 MTAC是更快和更小侵入性的方式来诱导左心室高血压，并使用于高通量研究的可能性。缩颈的成功可以采用高频经胸超声心动图，尤其是彩色多普勒和脉冲波多普勒，确定主动脉弓的流速进行验证和左，右颈动脉，血管的尺寸，并左心室功能和形态。一个成功的收缩也会触发显著病理变化，如间质及血管周围纤维化心肌细胞肥大。这里，MTAC的程序中描述，显示了如何在颈动脉所得流量的变化可以用超声心动图，大体形态，并在心脏组织病理学变化进行检查。

MTAC使得能够显著高血压在左心室及时的诱导。 如在图1看到的，主要工具的程序编制简单和最小的，仅需要2 - 4 30号针头以用聚氨酯管子被弯曲并保持在适当位置。手术过程本身也不太复杂，因为相比TAC，并且可以容易地进行。一旦甲状腺已收回，胸骨被切断，胸腺被移动以清除视图。主动脉弓是用于结扎过程（ ...

Watch this Scientific Journal Video about Minimally Invasive Transverse Aortic Constriction in Mice at JoVE.com

Minimally Invasive Transverse Aortic Constriction in Mice

微创横向主动脉缩窄（MTAC）节省常规横向主动脉缩窄（TAC）的要领，同时消除了气管插管使用呼吸机。它被证明是对左心室过载，特别是在翻译研究高通量研究一个非常理想的方法。

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 ...

minimally-invasive-transverse-aortic-constriction-in-mice

Research

JoVE Journal

Medicine

20.4K 次观看.  The University of Hong Kong. 微创横向主动脉缩窄（MTAC）节省常规横向主动脉缩窄（TAC）的要领，同时消除了气管插管使用呼吸机。它被证明是对左心室过载，特别是在翻译研究高通量研究一个非常理想的方法。 

视频: Minimally Invasive Transverse Aortic Constriction in Mice

In vitro Measurements of Tracheal Constriction Using Mice

Transgenic and knockout mice have been powerful tools for the investigation of the physiology and pathophysiology of airways1,2. In vitro tensometry of isolated tracheal preparations has proven to be a useful assay of airway smooth muscle (ASM) contractile response in genetically modified mice. These in vitro tracheal preparations are relatively simple, provide a robust response, and retain both functional cholinergic nerve endings and muscle responses, even after long incubations.
Tracheal tensometry also provides a functional assay to study a variety of second messenger signaling pathways that affect contraction of smooth muscle. Contraction in trachea is primarily mediated by parasympathetic, cholinergic nerves that release acetylcholine onto ASM (Figure 1). The major ASM acetylcholine receptors are muscarinic M2 and M3 which are Gi/o and Gq coupled receptors, respectively3,4,5. M3 receptors evoke contraction by coupling to Gq to activate phospholipase C, increase IP3 production and IP3-mediated calcium release from the sarcoplasmic reticulum3,6,7. M2/Gi/o signaling is believed to enhance contractions by inhibition of adenylate cyclase leading to a decrease in cAMP levels5,8,9,10. These pathways constitute the so called "pharmaco-contraction coupling" of airway smooth muscle11. In addition, cholinergic signaling through M2 receptors (and modulated by M3 signaling) involves pathways that depolarize the ASM which in turn activate L-type, voltage-dependent calcium channels (Figure 1) and calcium influx (so called "excitation-contraction coupling")4,7. More detailed reviews on signaling pathways controlling airway constriction can be found4,12. The above pathways appear to be conserved between mice and other species. However, mouse tracheas differ from other species in some signaling pathways. Most prominent is their lack of contractile response to histamine and adenosine13,14, both well-known ASM modulators in humans and other species5,15.
Here we present protocols for the isolation of murine tracheal rings and the in vitro measurement of their contractile output. Included are descriptions of the equipment configuration, trachea ring isolation and contractile measurements. Examples are given for evoking contractions indirectly using high potassium stimulation of nerves and directly by depolarization of ASM muscle to activate voltage-dependent calcium influx (1. high K+, Figure 1). In addition, methods are presented for stimulations of nerves alone using electric field stimulation (2. EFS, Figure 1), or for direct stimulation of ASM muscle using exogenous neurotransmitter applied to the bath (3. exogenous ACH, Figure 1). This flexibility and ease of preparation renders the isolated trachea ring model a robust and functional assay for a number of signaling cascades involved in airway smooth muscle contraction.

In vitro Measurements of Tracheal Constriction Using Mice

Transgenic mice have been extremely useful in ascribing physiological function to genes. As such, research in general, and functional studies of airway, in particular, have undergone a remarkable shift toward murine models. Here we provide protocols for in vitro trachea constriction studies to evaluate smooth muscle function in murine airway.

在利用老鼠的气管收缩的体外测量

Transgenic and knockout mice have been powerful tools for the investigation of the physiology and pathophysiology of airways1,2. In vitro tensometry of ...

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 ...

Minimally Invasive Establishment of Murine Orthotopic Bladder Xenografts

Orthotopic bladder cancer xenografts are the gold standard to study molecular cellular manipulations and new therapeutic agents&#160;in vivo. Suitable cell lines are inoculated either by intravesical instillation (model of nonmuscle invasive growth) or intramural injection into the bladder wall (model of invasive growth). Both procedures are complex and highly time-consuming. Additionally, the superficial model has its shortcomings due to the lack of cell lines that are tumorigenic following instillation. Intramural injection, on the other hand, is marred by the invasiveness of the procedure and the associated morbidity for the host mouse.
With these shortcomings in mind, we modified previous methods to develop a minimally invasive approach for creating orthotopic bladder cancer xenografts. Using ultrasound guidance we have successfully performed percutaneous inoculation of the bladder cancer cell lines UM-UC1, UM-UC3 and UM-UC13 into 50 athymic nude. We have been able to demonstrate that this approach is time efficient, precise and safe. With this technique, initially a space is created under the bladder mucosa with PBS, and tumor cells are then injected into this space in a second step. Tumor growth is monitored at regular intervals with bioluminescence imaging and ultrasound. The average tumor volumes increased steadily in in all but one of our 50 mice over the study period.
In our institution, this novel approach, which allows bladder cancer xenograft inoculation in a minimally-invasive, rapid and highly precise way, has replaced the traditional model.

The established technique to inoculate primary invasive orthotopic bladder cancer xenografts requires laparotomy and mobilization of the bladder. This procedure inflicts significant morbidity on the mice, is technically challenging and time-consuming. We therefore developed a high-precision, percutaneous approach utilizing ultrasound guidance.

微创建立小鼠原位膀胱移植瘤的

Orthotopic bladder cancer xenografts are the gold standard to study molecular cellular manipulations and new therapeutic agents&#160;in vivo. Suitable ...

Transverse Aortic Constriction in Mice

Transverse aortic constriction (TAC) in the mouse is a commonly used experimental model for pressure overload-induced cardiac hypertrophy and heart failure.1 TAC initially leads to compensated hypertrophy of the heart, which often is associated with a temporary enhancement of cardiac contractility. Over time, however, the response to the chronic hemodynamic overload becomes maladaptive, resulting in cardiac dilatation and heart failure.2 The murine TAC model was first validated by Rockman et al.1, and has since been extensively used as a valuable tool to mimic human cardiovascular diseases and elucidate fundamental signaling processes involved in the cardiac hypertrophic response and heart failure development. When compared to other experimental models of heart failure, such as complete occlusion of the left anterior descending (LAD) coronary artery, TAC provides a more reproducible model of cardiac hypertrophy and a more gradual time course in the development of heart failure. Here, we describe a step-by-step procedure to perform surgical TAC in mice. To determine the level of pressure overload produced by the aortic ligation, a high frequency Doppler probe is used to measure the ratio between blood flow velocities in the right and left carotid arteries.3, 4 With surgical survival rates of 80-90%, transverse aortic banding is an effective technique of inducing left ventricular hypertrophy and heart failure in mice.

Transverse aortic constriction (TAC) in the mouse is a commonly used experimental model to study mechanisms underlying cardiac hypertrophy and heart failure development. Here, we describe procedures to constrict the aorta to create a reproducible degree of cardiac hypertrophy in mice.

在小鼠体内的横向主动脉缩窄

Transverse aortic constriction (TAC) in the mouse is a commonly used experimental model for pressure overload-induced cardiac hypertrophy and heart ...

生物学

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.

The goal of this protocol is to noninvasively assess cardiac structural and functional changes in a mouse model of heart disease created by transverse aortic constriction, using B- and M-mode echocardiography and color/pulse wave Doppler imaging.

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 ...

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 ...

Operating Transverse Aortic Constriction with Absorbable Suture to Obtain Transient Myocardial Hypertrophy

Based on twice transverse aortic constrictions (TACs) in mice, it is proved that myocardial hypertrophic preconditioning (MHP) could attenuate cardiomyocyte hypertrophy and slow down progression to heart failure. For novices, however, the MHP model is usually quite difficult to establish because of the technical obstacles in ventilator operation, opening the chest repeatedly, and bleeding caused by debanding. To facilitate this model, to increase the surgical success rate and to reduce the incidence of bleeding, we switched to absorbable sutures for the first TAC combing with a ventilator-free technique. Using a 2-week absorbable suture, we demonstrated that this procedure could cause significant myocardial hypertrophy in 2 weeks; and 4 weeks after surgery, myocardial hypertrophy was almost completely regressed to the baseline. Using this protocol, the operators could master the MHP model easily with a lower operation mortality.

This protocol presents an improved method to obtain transient myocardial hypertrophy with absorbable suture, simulating left ventricular hypertrophy decrease after removing pressure overload. It could be valuable for the studies on myocardial hypertrophic preconditioning.

操作横向主动脉收缩与可吸收的缝合获得瞬时心肌萎缩

Based on twice transverse aortic constrictions (TACs) in mice, it is proved that myocardial hypertrophic preconditioning (MHP) could attenuate ...

A Modified Technique for Transverse Aortic Constriction in Mice

Transverse aortic constriction (TAC) is a frequently used surgery in research regarding heart failure and cardiac hypertrophy based on the formation of pressure overload in mouse models. The main challenge of this procedure is to clearly visualize the transverse aortic arch and precisely band the target vessel. Classical approaches perform a partial thoracotomy to expose the transverse aortic arch. However, it is an open-chest model that causes a rather large surgical trauma and requires a ventilator during the surgery. To prevent unnecessary trauma and simplify the operating procedure, the aortic arch is approached via the proximal proportion of the sternum, reaching and binding the target vessel using a small self-made retractor that contains a snare. This procedure can be conducted without entering the pleura cavity and does not need a ventilator or microsurgical operation, which leaves the mice with physiological breathing patterns, simplifies the procedure, and significantly reduces operation time. Due to the less invasive approach and less operation time, mice can undergo fewer stress reactions and recover rapidly.

The present protocol describes a modified and simplified technique with a minimally invasive transverse aortic constriction (TAC) procedure using a self-made retractor. This procedure can be conducted without a ventilator or microscope and introduces pressure overload, eventually leading to cardiac hypertrophy or heart failure.

一种改良的小鼠横主动脉收缩技术

Transverse aortic constriction (TAC) is a frequently used surgery in research regarding heart failure and cardiac hypertrophy based on the formation of ...

Transverse Aortic Arch Banding in Mouse Model: A Minimally Invasive Technique in Mice for Induction of High Pressure in the Left Ventricle

Source: Zaw, A. M. et al. <a href="https://www.jove.com/video/55293" target="_blank">Minimally Invasive Transverse Aortic Constriction in Mice</a>. J. Vis. Exp. (2017)
In this video, we demonstrate an experimental protocol for minimally invasive transverse aortic constriction in mice to examine pressure overload-induced heart failure.

小鼠横主动脉弓条带模型:小鼠诱导左心室高压的微创技术

Source: Zaw, A. M. et al. Minimally Invasive Transverse Aortic Constriction in Mice. J. Vis. Exp. (2017)
In this video, we demonstrate an experimental ...