Name: minimally invasive transverse aortic constriction in mice
Uploaded: 2017-03-14T15:00:00
Description: Watch this Scientific Journal Video about Minimally Invasive Transverse Aortic Constriction in Mice at JoVE.com

We would like to acknowledge the University Research Facility in Life Sciences (ULS) of The Hong Kong Polytechnic University for the provision of Vevo 2100 ultrasound system. Special thanks to Dr. Chunyi Wen from the Interdisciplinary Division of Biomedical Engineering, Hong Kong Polytechnic University, for training and facilitation. This work was supported by HK government RGC Grant GRF 17127215, 764812 and HKU6/CRF/11G to Billy K C Chow.

The protocol follows the guidelines of the Committee on the Use of Live Animals in Teaching and Research (CULATR) at the University of Hong Kong.
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 for 30 min or by other appropriate ...

<ol>
	<li>Rockman, H. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Segregation+of+atrial-specific+and+inducible+expression+of+an+atrial+natriuretic+factor+transgene+in+an+in+vivo+murine+model+of+cardiac+hypertrophy.">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="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transverse+aortic+constriction+in+mice.">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/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minimally+invasive+aortic+banding+in+mice:+effects+of+altered+cardiomyocyte+insulin+signaling+during+pressure+overload.">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/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Excessive+cardiac+insulin+signaling+exacerbates+systolic+dysfunction+induced+by+pressure+overload+in+rodents.">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/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+surgical+models+in+cardiovascular+research.">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/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+modified+murine+model+for+the+study+of+reverse+cardiac+remodelling.">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/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Doppler+estimation+of+reduced+coronary+flow+reserve+in+mice+with+pressure+overload+cardiac+hypertrophy.">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/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Echocardiography+in+translational+research:+of+mice+and+men.">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/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+heart+failure+by+minimally+invasive+aortic+constriction+in+mice:+reduced+peroxisome+proliferator-activated+receptor+gamma+coactivator+levels+and+mitochondrial+dysfunction.">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/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+Cardiac+Morphological+and+Functional+Changes+in+Mouse+Model+of+Transverse+Aortic+Constriction+by+Echocardiographic+Imaging.">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>

Rockman and colleagues devised the first method for aortic banding as a method to study pressure overload in the heart. This enabled research to begin to uncover the cellular and molecular consequences of hypertension and heart failure1. An improved method, minimally invasive transverse aortic constriction (MTAC), provides an amenable, time-dependent method for the induction of left ventricular pressure overload and heart failure, without the drawbacks of the conventional transverse aortic constri...

The overall purpose of this article is to demonstrate how transverse aortic constriction (TAC) in mice can be modified to produce a simpler and more expedient surgery. TAC was first introduced in 19911 and enabled molecular biologists to study the cellular and molecular pathways that lead to hypertrophy in the left ventricle and to heart failure, particularly in small animals with manipulated genomes2,3,4,5,6. Despite its efficacy at producing the desired pressure overload, the technique is ultimately limited by the difficulty in performing the procedure and by its low survival rate. A surgeon conducting TAC must be able to perform endotracheal intubation, thoracotomy, and use artificial ventilation in order to prevent lung collapse1.
Oftentimes, a simple and less invasive method is desired. As a consequence, minimally invasive transverse aortic constriction (MTAC) was devised3. Though the outcome (specifically, left ventricular hypertrophy) is the same, the procedure involves significantly fewer apparatuses and less damage to the animal. MTAC proves to be a desirable method that has a greater survival rate, above 90%, and has an operation time of only 15 to 25 min. The infrequent cases of death after successful surgery can be attributable to too-tight constriction of the aortic arch, resulting in tremendous left ventricular overload and fatal reduction of blood supply to critical organs such as the kidneys.
After the procedure is completed, echocardiography can be used to evaluate the success of banding and the cardiac morphology and function. A high-frequency ultrasound system can be utilized to measure the diameter and flow changes in the left and right carotid arteries, to visualize the aortic arch constriction for peak flow velocity measurements, and to determine the left ventricle wall thickness and functional parameters7,8. After euthanasia, the organs can also be collected for histopathological studies with hematoxylin and eosin staining and Picrosirius collagen staining, the latter being particularly useful for the observation of fibrosis.

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			<td>1 inch 30 Gauge Needles</td>
			<td>BD, Franklin Lakes, NJ 07417, USA.&#160;</td>
			<td>305128</td>
			<td>Curved as in the procedure and Figure 1</td>
		</tr>
		<tr>
			<td>27 Gauge Needle</td>
			<td>BD, Franklin Lakes, NJ 07417, USA.&#160;</td>
			<td>301629</td>
			<td>Make blunt and smooth for spacer</td>
		</tr>
		<tr>
			<td>6/0 Dafilon</td>
			<td>B. Braun, 34212 Melsungen, Hessen, Germany.</td>
			<td>C0933066</td>
			<td></td>
		</tr>
		<tr>
			<td>6/0 Silkam</td>
			<td>B. Braun, 34212 Melsungen, Hessen, Germany.</td>
			<td>C0762067</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile gloves</td>
			<td>A.R. Medicom, Inc (Asia), Hong Kong.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Cotton Applicator</td>
			<td>Mannings, Quarry Bay, Hong Kong.</td>
			<td></td>
			<td>Local Shopping Center</td>
		</tr>
		<tr>
			<td>Delapitory Cream</td>
			<td>Veet (Hong Kong), Kwun Tong, Kowloon, Hong Kong</td>
			<td></td>
			<td>Local Shopping Center</td>
		</tr>
		<tr>
			<td>Lexer-Baby Scissor</td>
			<td>FST, British Columbia V7H 0A6, Canada.</td>
			<td>14078-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Curved Iris Forcep</td>
			<td>FST, British Columbia V7H 0A6, Canada.</td>
			<td>11065-07</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro Olsen-Hegar Needle Holder</td>
			<td>WPI, Sarasota, FL 34240, USA.&#160;</td>
			<td>501989</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereo Micrioscope</td>
			<td>WPI, Sarasota, FL 34240, USA.&#160;</td>
			<td>PZMIII-BS</td>
			<td></td>
		</tr>
		<tr>
			<td>GenTeal Gel</td>
			<td>Novartis, East Hanover, NJ 07936, USA.&#160;</td>
			<td></td>
			<td>Local Pharmacy</td>
		</tr>
		<tr>
			<td>Heating Pad</td>
			<td>Kent Scientific Corporation, Torrington, CT 06790, USA.&#160;</td>
			<td>DCT-20</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical tape</td>
			<td>Laboratory Animal Unit</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ketamine and Xylazine</td>
			<td>Laboratory Animal Unit</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Betadine</td>
			<td>Laboratory Animal Unit</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Buprenorphine</td>
			<td>Laboratory Animal Unit</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

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.

MTAC enables the induction of significant hypertension in the left ventricle in a timely manner.
As seen in Figure 1, the preparation of the primary tools for the procedure is simple and minimal, requiring only 2 - 4 30-gauge needles to be bent and held in place with a polyurethane tube. The surgical procedure itself is also less complicated, as compared to TAC, and can be performed easily. Once the thyroid has ...

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

Minimally Invasive Transverse Aortic Constriction in Mice

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.

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

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