eoe sub articles

EoE Sub Articles

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.
1. Operation Site Preparation
<ol>
	<li>Disinfect the operation site with 75% isopropyl alcohol. Adjust the heating pad temperature to 37 &#176;C to avoid changes in heart and respiratory rates of the subject animal.</li>
	<li>Use surgical instruments sterilized in a gravity displacement sterilizer at 121 &#176;C fo...

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.

<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/20752/20752_Figure 1.jpg" /> 
Figure 1: Process of forming the desired needle hooks by bending a 1-in, 30-gauge needle tip. (A) The original 1-in, 30-gauge needle tip. (B) Grasp the needle tip with the needle holder and bend approximately halfway along its length. Bend the needle into a loop, using the needle holder and the hands, as necessary, to form the loop pictured in th...

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. Minimally Invasive Transverse Aortic Constriction in Mice. J. Vis. Exp. (2017)
In this video, we demonstrate an experimental ...

Minimally invasive transverse aortic constriction or aortic arch banding is a simplified procedure to generate a mouse model of cardiovascular disease. Begin with an anesthetized mouse in the supine position. Shave the neck and the chest region. Perform a midline incision to expose the underlying muscle layer.
Slit through the muscle layer to access the thyroid gland and sternum. Next, separate the tracheal muscles and cut the sternum to reveal the underlying thymus gland. Separate the thymus lobes from one another to reveal the transverse aortic arch and carotid arteries. Place a curved needle under the aortic arch and push it out between the vessel wall.
Pass a ligature through this perforation and place a spacer in the loop to adjust the loop diameter. Now, tighten the suture around the aorta to occlude the vessel. This increases the blood-flow velocity in the right carotid artery, causing increased blood pressure in the ascending aorta and the left ventricle.
Thereafter, remove the spacer and cut the thread. Then, reposition the organs and suture the skin. Transfer the mouse to the recovery cage and monitor its cardiac function. Aortic banding induces left ventricular overload, leading to thickening of chamber walls and diminished cardiac output.

transverse-aortic-arch-banding-mouse-model-minimally-invasive

Research

JoVE Encyclopedia of Experiments

Biology

Rodent Models

Adult

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.

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

JoVE Journal

Medicine

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.

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.

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

Transcript