Name: operating transverse aortic constriction with absorbable suture to obtain transient myocardial hypertrophy
Uploaded: 2020-09-09T14:45:00.000+00:00
Duration: 7 min 2 s
Description: Watch this Scientific Journal Video about Operating Transverse Aortic Constriction with Absorbable Suture to Obtain Transient Myocardial Hypertrophy at JoVE.com

这项工作得到了中国国家自然科学基金委员会（81770271:给Y，廖），中国国家自然科学基金联合基金（U1908205:给Y，廖）和广州市科技规划项目（201804020083:廖博士）的资助。

所有程序都是按照美国国家卫生研究院出版的《 实验室动物的护理和使用 指南》进行的（NIH出版物第85-23号，1996年修订）。C57BL/6J雄性小鼠（8~10周，20~25克）由南方医科大学动物中心提供。
1. 术前准备
<ol><li>用针架捏掉 25 G 针的尖端，用像支架这样的硬物将其钝化。</li>
	<li>通过针头传递一个5+0可吸收的缝合线，然后弯曲到90°与持有人13。 注:根据不同的研究目的，研究者可以选择吸收时间不同的可吸收线。在此协议中，我们使用 2 周的可吸收缝合收缩主动脉拱门。</li>
	<li>将另一根 25 G 针弯曲至 120°，并用支架平滑尖端，用作配扎步骤中的垫片。 注:25 G 针头用作体重 （BW） + 25 g 的小鼠的垫片。使用 26 G 针对小鼠与 19–24 g BW.</li>
	<li>用75%的酒精对手术现场进行消毒。</li>
	<li>将加热垫温度调整为 37 °C。</li>
	<li>准备消毒手术器械（包括1把眼科剪刀、1把微剪刀、2把微手术肘钳、1个针架和1个微型针架）。</li>
</ol>2. 麻醉和剃须的感应
<ol><li>通过在盐溶液中稀释的西拉津（5毫克/千克）和氯胺酮（100毫克/千克）的混合物（0.9%NaCl）进行腹膜注射，使小鼠麻醉。用负踏板戒断反射确认完全麻醉。</li>
	<li>通过用缝合针固定切口和用胶带固定四肢，使鼠标保持超细位置。</li>
	<li>涂抹脱毛霜，去除颈部和西福的头发。用碘对该地区进行消毒，然后用75%的酒精消毒。</li>
</ol>3. 手术
<ol><li>用手术刀在超胸缺口和胸部之间的中线位置切口超过 10 毫米。然后，将皮肤和表面筋膜分开。</li>
	<li>通过从骨部角度计算肋骨来识别第一个间距空间。在第一个间歇空间中执行切口，并尽可能靠近胸骨。用肘部钳子模糊地穿透它， 打开这个空间。</li>
	<li>轻轻地将帕奇马和胸腺分开，直到可以看到横向主动脉拱门。 注意:不要损坏胸膜，以避免肺气管。</li>
	<li>通过主动脉之间的主动脉拱门下的5–0可吸收缝合，用闩锁针14。请确保手术场内可见胸动脉、左侧普通胡萝卜动脉和左下腹动脉。</li>
	<li>将垫片放在第 1.3 步准备的隔横主动脉上，并在垫片上执行双结，并在第 3.4 步中用缝合线进行。 注意:垫片的尖端必须钝，以避免在取出横向主动脉时损坏它。</li>
	<li>快速但轻轻地拆下垫片，然后切开缝合线的末端。</li>
	<li>使用 5–0 尼龙缝合线关闭第一个间歇空间和皮肤。用75%的酒精再次消毒皮肤。</li>
	<li>将鼠标放在加热垫上，以促进恢复。手术后头3天静脉注射丁丙诺啡（0.1毫克/千克，q12h）。</li>
	<li>当老鼠恢复知觉时，将鼠标放回笼子，在12小时光/暗循环室中。</li>
	<li>执行与上述所有步骤相同的虚假手术，但没有收缩（步骤 3.5）。</li>
	<li>为丝绸缝合组执行手术，与上述所有步骤相同，但在第 1.2 步使用 5–0 丝缝合。</li>
</ol>4. 成功配对和测量的回声心电图评估
<ol><li>手术后在日（D）7进行心电图评估。</li>
	<li>麻醉小鼠3%通过吸入吸入感应，1.5%保持麻醉深度，0.5+1 L/分钟氧气流速。</li>
	<li>将鼠标置于平台上的超平位置，保持在 37 °C，并将四肢贴在电极上。</li>
	<li>用脱毛霜去除胸毛，在鼠标的胸部涂抹超声波耦合剂。</li>
	<li>使用 30 MHz 探头评估横向主动脉收缩。<ol>
<li>将平台向最左边倾斜。将探针保持垂直位置，并沿着右侧栏杆线将其放在胸部。然后，在 B 模式下操纵 X 轴和 Y 轴，直到主动脉拱门清晰可见。</li>
		<li>通过B模式定位收缩以获得主动脉拱视图11。使用彩色多普勒模式和脉冲波测量峰值流速，并选择速度超过 3，000 mm/s 的小鼠作为 TAC 组（值基于初步实验）。</li>
		<li>根据伯努利方程11的修改版本计算压力梯度: 压力梯度 =4 x V最大2。 注:横向主动脉收缩模型的理想压力梯度范围为40-80 mmHg11。</li>
		<li>使用 Cine 商店和帧存储保存数据和图像。</li>
	</ol>
</li>
	<li>使用 30 MHz 探头评估左心室 （LV） 的尺寸和收缩度。<ol>
<li>将平台重置为水平位置。相对于左侧的抛物线，将探头保持在 30° 逆时针。</li>
		<li>使用 B 模式并操纵 X 和 Y 以获得清晰而完整的心轴视图。</li>
		<li>按 M 模式显示指示线。使用 Cine 商店和框架存储获取图像，以以后测量 LV 腔室尺寸、部分缩短和 LV 壁厚度。</li>
	</ol>
</li>
	<li>一旦完成，停止异氟烷吸入，让小鼠从麻醉中恢复过来。然后，将动物送回笼子，在12小时光/暗循环室。</li>
	<li>在手术后的D14和D28上，重复上述步骤测量心脏参数，然后收获心脏进行组虫学研究。</li>
</ol>

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作者没有什么可透露的。

在心脏非缺血预科中，仍然存在着一个大大不足的区域。根据我们以前的研究，我们改用可吸收的缝合线来改善心肌肥大预后模式。
在先前的报告中，许多调查人员使用丝绸缝合来收缩主动脉拱门8号、14号、15号。丝绸缝合很容易获得，经常用于手术伤口缝合，组织结块和组织固定。在此协议中，我们用可吸收的缝合替换了第一个 TAC 的丝绸缝合线。我们发现收缩中的血流速度仍然达到3000毫米/s或更多，持续了2周，这足以作为一种长期的肥大刺激。然后，它将返回到 D28 的基线。然而，很难控制可吸收缝合物的吸收时间。吸收时间与材料和一批可吸收的缝合、组织的适应性和收缩时的紧绷性有关。我们之前发现收缩越紧，吸收时间越少，但与此同时，老鼠的死亡率也会增加。因此，我们选择峰值速度在3000毫米/s左右作为标准，以便吸收时间可以在2周内得到控制，小鼠的存活率也可以提高。更重要的是，使用可吸收的缝合可以将开胸时间缩短到两次，从而降低手术难度，提高模型的成功率。
手术期间，小鼠的生命支持通常需要呼吸机。据报道，大鼠主动脉拱门可以收缩没有呼吸机使用超强的fossa方法15。然而，这需要削减小鼠的胸骨，这可能延长手术恢复时间。在这项研究中，我们选择了这种方法:收缩第一个靠近胸骨的间歇空间，进行手术。这是一个微创的方法，通过横向胸腔切除术14。令人惊讶的是，如果切口离胸骨尽可能近，我们可以在没有呼吸机的情况下执行 TAC。这种方法还可以有效地避免呼吸机相关的技术操作和伤害12。此外，通过切口进入小鼠的中间，主动脉拱门被清楚地暴露出来，因为手术领域几乎没有对胸腺组织和其他血管的干扰。
虽然在整个操作过程中不使用呼吸机是很方便的，但改进后的方法仍然具有因胸膜损伤引起的肺气管损伤的风险。有一些建议，这可能是有用的，以避免损害胸花。尽可能把针尖打钝。进入介质后，在整个操作过程中尽可能保持肘部钳尖的垂直。在连体过程中，将垫片沿前中线放入介质中。
总之，我们改进了使用可吸收缝合物进行心肌肥大和回归的小鼠模型，在建立心肌肥大先决条件模型、探索肥大退行机制、研究左心室可逆改造时间等方面具有许多潜在的应用。

缺血性先导是一种现象，诱发短暂的非致命性缺血发作和对心脏的再灌注，并有能力显著减少心肌损伤1。鉴于缺血性先决条件的明显临床意义，如限制心肌梗塞大小2和抑制心室心肌梗塞后心肌复明3，已经有很多研究来解剖机制潜在的心防作用诱导的先决条件4，5。相比之下，其他非缺血的先决条件却很少受到关注。心脏肥大可能钝化在主动脉狭窄患者进行主动脉瓣更换6。在存在病理心肌萎缩状态的地方，很少报告先决条件原理。
1991年，罗克曼等人首次建立了通过横向主动脉收缩（TAC）7导致左心室肥大的小鼠模型。通过在小鼠中两次操作TAC，我们先前已经证明心肌肥大预后（MHP）会导致心脏短暂性肥大刺激，从而使心脏在未来8月对持续的肥大压力更具抵抗力。MHP模型的特点已通过超声波生物显微镜和血动力学评估9得到验证。构建模型的要点是执行胸腔切除术三次，TAC 一周，解散一周，二级 TAC 6 周。然而，去组织可能导致出血，这使得新手难以掌握，也难以推广。此外，给小鼠进行管网也是一项技术挑战。不当的受管可能导致气管损伤、肺气管损伤，甚至导致小鼠死亡。因此，在构建MHP模型的同时，改进一些程序是必要和有价值的。
为了降低模型的难度并增加其成功率，我们切换到可吸收的缝合线为第一个TAC，并通过测量压力梯度通过回声心动图10下主动脉收缩监测模型的成功。根据我们的初步实验，在压力梯度过低的小鼠中很难诱发足够的心肌肥大，而压力梯度过高的小鼠会发展成急性心力衰竭甚至死亡。模型的理想压力梯度范围为 40–80 mmHg11。此外，这个实验没有依靠呼吸机，它可以有效地避免呼吸机相关的技术操作和伤害12。

<table><tbody><tr><td>Absorbable suture (5-0)</td><td>Shandong Kang Lida Medical Products Co., Ltd</td><td>5-0</td><td>Ligation</td></tr><tr><td>Animal ultrasound system VEVO2100</td><td>Visual Sonic</td><td>VEVO2100</td><td>Echocardiography</td></tr><tr><td>Cold light illuminator</td><td>Olympus</td><td>ILD-2</td><td>Light</td></tr><tr><td>Heat pad- thermostatic surgical system (ALC-HTP-S1)</td><td>SHANGHAI ALCOTT BIOTECH CO</td><td>ALC-HTP-S1</td><td>Heating</td></tr><tr><td>Isoflurane</td><td>RWD life science</td><td>R510-22</td><td>Inhalant anaesthesia</td></tr><tr><td>Matrx VIP 3000 Isofurane Vaporizer</td><td>Midmark Corporation</td><td>VIP 3000</td><td>Anesthetization</td></tr><tr><td>Medical nylon suture (5-0)</td><td>Ningbo Medical Needle Co.</td><td>5-0</td><td>Close the skin</td></tr><tr><td>Pentobarbital sodium salt</td><td>Merck</td><td>25MG</td><td>Anesthetization</td></tr><tr><td>Precision electronic balance</td><td>Denver Instrument</td><td>TB-114</td><td>Weighing sensor</td></tr><tr><td>Self-made spacer</td><td></td><td></td><td>25-gauge needle</td></tr><tr><td>Silk suture (5-0)</td><td>Yangzhou Yuankang Medical Devices Co., Ltd.</td><td>5-0</td><td>Ligation</td></tr><tr><td>Small animal microsurgery equipment</td><td>Napox</td><td>MA-65</td><td>Surgical instruments</td></tr><tr><td>Transmission Gel</td><td>Guang Gong pai</td><td>250ML</td><td>Echocardiography</td></tr><tr><td>Veet hair removal cream</td><td>Reckitt Benchiser</td><td>RQ/B 33 Type 2</td><td>Remove hair of mice</td></tr><tr><td>Vertical automatic electrothermal pressure steam sterilizer</td><td>Hefei Huatai Medical Equipment Co.</td><td>LX-B50L</td><td>Auto clean the surgical instruments</td></tr></tbody></table>

operating transverse aortic constriction with absorbable suture to obtain transient myocardial hypertrophy

基于小鼠两次横向主动脉收缩（TACs），证明心肌肥大预后（MHP）可以减轻心肌细胞肥大，减缓心力衰竭的进展。然而，对于新手来说，MHP模型通常很难建立，因为呼吸机操作的技术障碍，反复打开胸部，以及脱体引起的出血。为了促进这种模式，提高手术成功率和减少出血的发生率，我们改用可吸收的缝合线进行第一次TAC梳理，采用无呼吸机技术。使用2周的可吸收缝合，我们证明这个程序可能会导致严重的心肌萎缩在2周:手术后4周，心肌萎缩几乎完全退回到基线。使用此协议，操作员可以轻松掌握 MHP 模型，降低操作死亡率。

在这项研究中，我们随机将45只小鼠分成三组，分别是假象组、丝缝组和可吸收缝合组（TAC之后D0（基线）、D14和D28上每组的数量分别为15、10和5）。手术后的D7、D14、D21和D28，收缩的峰值速度由心电图确定。我们发现，在TAC之后的第二周，收缩处的血流速度仍然大于3，000毫米/秒，即使使用可吸收的缝合线收缩主动脉拱门（图1A）。此外，可吸收缝合组收缩时的压力梯度在2周内维持在40 mmHg以上（图1B）。有趣的是，手术后的第四周没有收缩，这表明可吸收的缝合线已被完全吸收。
我们还发现，末端硅胶的左心室后壁厚度增加，末端隔膜左心室内部直径在TAC（图2A-C）之后的D14上略有下降。有趣的是，可吸收缝合组末端硅胶的左心室后壁厚度在 TAC 之后的 D28 上大幅倒退，与基线水平没有显著差异。此外，使用可吸收的缝合线制作模型不会影响左心室的弹出部分（图2D）。
与假丝缝合组相比，丝绸缝合组和可吸收缝合组的硬件/BW比率增加了30%。在TAC之后的D28上，心肌肥大退步，比例回落到可吸收缝合组的基线水平（图3A），而丝缝组的比例增加了64%。H&E染色的结果也支持心脏肥大（图3B）。总之，可吸收缝合适合引起瞬态病理肥大刺激，符合心肌肥大预制模型的要求。
定量数据被作为平均± SD 呈现。假缝、丝缝和可吸收缝合之间的比较是使用单向 ANOVA 进行的， 然后是邦费罗尼的事后比较。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/61686/61686fig01.jpg"> 图1:脉冲波多普勒成像和收缩的峰值速度和压力梯度的结果。在 D0 （基线）， D7， D14， D21 和 D28 后 TAC 使用丝绸缝合或可吸收的缝合， 主动脉拱门或收缩由脉冲波多普勒测量.（A） 丝绸缝合组和可吸收缝合组手术后D0（基线）、D14和D28峰值速度的代表成像。可吸收缝合组的血流速度恢复到基线，而手术后D28的丝缝组的血流速度仍大于3，000毫米/s。（B） 压力梯度是根据修改后的 Bernoulli 方程计算的:压力梯度 = 4 x V最大2 （V= 最大峰值速度）。*:p&0.05与假。#:p&0.05与丝绸缝合组（D0（基线）、D14和D28上每个组的数量分别为15、10和5）。作为平均± SD 呈现的数据。 <a href="https://www.jove.com/files/ftp_upload/61686/61686fig01large.jpg" target="_blank">请单击此处查看此图的更大版本。</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/61686/61686fig02.jpg"> 图2:结构和收缩功能的左心室参数。（A） 从丝绸缝合组的左心室 （LV） 和 TAC 后 D0 （基线）、 D14 和 D28 上的可吸收缝合组进行 M 模式成像。在丝缝合组中，LV壁厚度在末端焦油的代表性图像约为 0.70 mm （D0） 至 1.089 mm （D28）。至于可吸收的缝合组，壁厚约为0.658毫米（D28），几乎返回基线。（B） 左心室后壁厚度在末端硅胶 （LVPWd）。（C） 左心室内部直径在末端硅胶 （LVIDD）。（D） 左心室弹出分数 （EF）。*:p&0.05与假同时（D0（基线）、D14和D28上每个组的数量分别为15、10和5）。作为平均± SD 呈现的数据。 <a href="https://www.jove.com/files/ftp_upload/61686/61686fig02large.jpg" target="_blank">请单击此处查看此图的更大版本。</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/61686/61686fig03.jpg"> 图3:心肌肥大预后模型中的可逆心脏肥大。（A） 心脏重量 （HW） 与体重 （BW） 比率。（B） 带有 H&E 染色的心脏组织切片（比例杆 = 50μm）。丝缝合组的心肌细胞从D14显著扩大至D28，而可吸收缝合组的细胞大小大多在D28上退步。*:p&0.05与假同时（D0（基线）、D14和D28上每个组的数量分别为15、10和5）。作为平均± SD 呈现的数据。 <a href="https://www.jove.com/files/ftp_upload/61686/61686fig03large.jpg" target="_blank">请单击此处查看此图的更大版本。</a>

Watch this Scientific Journal Video about Operating Transverse Aortic Constriction with Absorbable Suture to Obtain Transient Myocardial Hypertrophy at JoVE.com

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

该协议提出了一个改进的方法，以获得可吸收的缝合的瞬时心肌肥大，模拟左心室肥大减少后，消除压力过载。它可能对心肌肥大先天性研究很有价值。

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 ...

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Nanyang Technological University

Research

JoVE Journal

Medicine

6.2K 次观看.  Southern Medical University. 该协议提出了一个改进的方法，以获得可吸收的缝合的瞬时心肌肥大，模拟左心室肥大减少后，消除压力过载。它可能对心肌肥大先天性研究很有价值。

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

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 ...

科研

医学

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 ...

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 ...

Studying Left Ventricular Reverse Remodeling by Aortic Debanding in Rodents

To better understand the left ventricular (LV) reverse remodeling (RR), we describe a rodent model wherein, after aortic banding-induced LV remodeling, mice undergo RR upon removal of the aortic constriction. In this paper, we describe a step-by-step procedure to perform a minimally invasive surgical aortic debanding in mice. Echocardiography was subsequently used to assess the degree of cardiac hypertrophy and dysfunction during LV remodeling and RR and to determine the best timing for aortic debanding. At the end of the protocol, terminal hemodynamic evaluation of the cardiac function was conducted, and samples were collected for histological studies. We showed that debanding is associated with surgical survival rates of 70-80%. Moreover, two weeks after debanding, the significant reduction of ventricular afterload triggers the regression of ventricular hypertrophy (~20%) and fibrosis (~26%), recovery of diastolic dysfunction as assessed by the normalization of left ventricular filling and end-diastolic pressures (E/e&#39;&#160;and LVEDP). Aortic debanding is a useful experimental model to study LV RR in rodents. The extent of myocardial recovery is variable between subjects, therefore, mimicking the diversity of RR that occurs in the clinical context, such as aortic valve replacement. We conclude that the aortic banding/debanding model represents a valuable tool to unravel novel insights into the mechanisms of RR, namely the regression of cardiac hypertrophy and the recovery of diastolic dysfunction.

Here we describe a step-by-step protocol of surgical aorta debanding in the well-established mice model of aortic-constriction. This procedure not only allows studying the mechanisms underlying the left ventricular reverse remodeling and regression of hypertrophy but also to test novel therapeutic options that might accelerate myocardial recovery.

研究左心室反向改造由主动脉脱体在啮齿动物

To better understand the left ventricular (LV) reverse remodeling (RR), we describe a rodent model wherein, after aortic banding-induced LV remodeling, ...

O-Ring Aortic Banding Versus Traditional Transverse Aortic Constriction for Modeling Pressure Overload-Induced Cardiac Hypertrophy

Aortic banding in mice is one of the most commonly used experimental models for cardiac pressure overload-induced cardiac hypertrophy and the induction of heart failure. The previously used technique is based on a threaded suture around the aortic arch tied over a blunted 27 G needle to create stenosis. This method depends on the surgeon manually tightening the thread and, thus, leads to high variance in the diameter size. A newly refined method described by Melleby et al. promises less variance and more reproducibility after surgery. The new technique, o-ring- aortic banding (ORAB), uses a non-slip rubber ring instead of a suture with a thread, resulting in reduced variation in pressure overload and reproducible phenotypes of cardiac hypertrophy. During surgery, the o-ring is placed between the brachiocephalic and left carotid arteries. Successful constriction is confirmed by echocardiography. After 1 day, correct placement of the ring results in an increased flow velocity in the transverse aorta over the o-ring-induced stenosis. After 2 weeks, impaired cardiac function is proven by decreased ejection fraction and increased wall thickness. Importantly, besides less variance in the diameter size, ORAB is associated with lower intra- and post-operative mortality rates compared with transverse aortic constriction (TAC). Thus, ORAB represents a superior method to the commonly used TAC surgery, resulting in more reproducible results and a possible reduction in the number of animals needed.

The present protocol describes a new technique of aortic banding in mice to induce pressure overload cardiac hypertrophy. For banding, a rubber ring with a fixed inner diameter is used. This new technique promises less variance and more reproducible data for future experiments.

O形环主动脉束带与传统横主动脉收缩在压力超负荷引起的心脏肥大建模中的比较

Aortic banding in mice is one of the most commonly used experimental models for cardiac pressure overload-induced cardiac hypertrophy and the induction of ...

用于研究压力超负荷诱发的心力衰竭的升主动脉束带

A Minimally Invasive Model of Aortic Stenosis in Swine

Large animal models of heart failure play an essential role in the development of new therapeutic interventions due to their size and physiological similarities to humans. Efforts have been dedicated to creating a model of pressure-overload induced heart failure, and ascending aortic banding while still supra-coronary and not a perfect mimic of aortic stenosis in humans, closely resembling the human condition.
The purpose of this study is to demonstrate a minimally invasive approach to induce left ventricular pressure overload by placing an aortic band, precisely calibrated with percutaneously introduced high-fidelity pressure sensors. This method represents a refinement of the surgical procedure (3Rs), resulting in homogenous trans-stenotic gradients and reduced intragroup variability. Additionally, it enables swift and uneventful animal recovery, leading to minimal mortality rates. Throughout the study, animals were followed for up to 2 months after surgery, employing transthoracic echocardiography and pressure-volume loop analysis. However, longer follow-up periods can be achieved if desired. This large animal model proves valuable for testing new drugs, particularly those targeting hypertrophy and the structural and functional alterations associated with left ventricular pressure overload.

作者聚焦:开发用于可靠且可重复的心血管研究的微创大型动物模型 

This protocol describes a minimally invasive surgical procedure for ascending aortic banding in swine.

猪主动脉瓣狭窄的微创模型

Large animal models of heart failure play an essential role in the development of new therapeutic interventions due to their size and physiological ...

操作横向主动脉收缩与可吸收的缝合获得瞬时心肌萎缩

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此视频中的章节

大鼠建立压力超负荷心肌肥厚模型在升主动脉缩窄

心脏重构通过大鼠腹主动脉缩窄的模型

微创横向主动脉缩窄小鼠

小鼠横主动脉狭窄诱导左心室肥厚的技术研究

诱导小鼠横向主动脉狭窄的闭合胸模型

研究左心室反向改造由主动脉脱体在啮齿动物

O形环主动脉束带与传统横主动脉收缩在压力超负荷引起的心脏肥大建模中的比较

猪主动脉瓣狭窄的微创模型

猪主动脉瓣狭窄的微创模型

猪主动脉瓣狭窄的微创模型