Los autores reconocen Departamento de Biotecnología del Gobierno de la India para el apoyo financiero de este proyecto. Ajith Kumar GS fue apoyado con becas de investigación senior del Consejo de Investigación Científica e Industrial, Gobierno de la India y Binil Raj con beca de investigación de alto nivel de Consejo Indio de Investigación Médica, Gobierno de la India.

Los experimentos con animales se realizaron después de obtener la aprobación del Comité de Ética Animal Institucional. Ratas Wistar fueron alojados bajo una oscuridad de 12 horas para el ciclo de luz, temperatura constante (24 ± 2 ° C) con comida y agua ad libitum (según las directrices CPCSEA). 1) Cuidado Pre-operatorio y anestesia <ol><li> Mantener la rata (aproximadamente 200 g de peso corporal) en virtud de antibiótico paraguas 24 horas antes de la cirugía mediante la administración de amoxicilina por vía oral (dosis: 500 mg / L de agua). </li><li> Esterilice todos los instrumentos quirúrgicos (tales como tijeras, pinzas, aplicador de grapas, agujas de sutura, y soporte de la aguja) en autoclave a 121 ° C durante 15 min. </li><li> Utilice una almohadilla de calentamiento para mantener la temperatura corporal del animal alrededor de 37 ° C para evitar una rápida disminución en la frecuencia cardíaca. </li><li> Tenga cuidado para evitar la deshidratación del animal antes y durante la cirugía. </li><li> Se anestesia la rata en una cámara de inducción con 3% de isoflurano mezclado con0,5-1,0 L / min 100% de oxígeno; mantener la anestesia con 1,5% de isoflurano. </li><li> Compruebe el reflejo pedal para confirmar la anestesia exitosa. </li></ol> 2) Preparación del sitio quirúrgico <ol><li> Mantenga la rata en la parte superior de una almohadilla térmica de temperatura controlada en la posición supina. </li><li> Coloque una banda de goma sobre los dientes delanteros de la rata para mantener al animal en posición mientras se mantiene la anestesia con un cono de nariz. </li><li> Retire la piel del cuello y región del pecho izquierdo de la rata (preferiblemente usando una máquina de afeitar eléctrica). </li><li> Desinfectar la zona quirúrgica con solución de povidona yodada y luego con 70% de alcohol etílico. </li><li> Utilice un paño estéril para exponer sólo el sitio quirúrgico durante el procedimiento quirúrgico. Nota: Como una opción adicional para el cuidado de los animales, 0,25% bupivicaína Identificación (2,5 mg / kg) se puede incorporar antes de la incisión en cada sitio de la incisión para la anestesia local / analgesia. </li></ol> 3) Intubación traqueal en rata <ol><li> Hacer una pequeña incisión en la piel paralela a la tráquea utilizando una cuchilla quirúrgica estéril y separar cuidadosamente el tejido subyacente con el fin de exponer la tráquea. </li><li> Aplicar un empate de 4-0 seda hilo de sutura debajo de la tráquea y levante suavemente la eliminatoria hacia arriba. </li><li> Hacer una incisión a mitad de camino entre dos anillos de cartílago e insertar la cánula traqueal en la tráquea de la rata. </li><li> Conectar la cánula traqueal a un ventilador de roedor para el mantenimiento de una frecuencia respiratoria de 50 respiraciones / min, volumen de marea de 1,70 ml y el tiempo de inspiración de 0,60 seg (de rata con 200 g de peso corporal). </li></ol> 4) La constricción de la aorta ascendente <ol><li> Después de detectar la posición de las costillas con los dedos, hacer una incisión en la piel de alrededor de 2 cm en la pared torácica izquierda entre las segunda y tercera costillas. </li><li> Se separa la capa músculos intercostales por capa y hacer una incisión de aproximadamente 1,5 cm de largo entre las segunda y tercera costillas. (El cuidado debe ser toman para evitar cualquier daño a los pulmones mientras que hace la incisión entre las costillas) </li><li> Repliegue de las costillas y ubique la parte ascendente de la aorta. </li><li> Coloque un pequeño clip de titanio de tamaño alrededor de la aorta ascendente con la ayuda de un aplicador con lo que la constricción de la aorta al 50-60% del diámetro inicial. </li><li> Después de la constricción de la aorta, la aproximación de las segunda y tercera costillas con 3,0 de prolene en un patrón de sutura interrumpida. Al mismo tiempo, poner en pausa el respirador durante unos 2-4 segundos con el fin de volver a inflar los pulmones. </li><li> Aproximar las capas musculares con 3,0 puntos de sutura de prolene y la piel con 4,0 puntos de seda en un patrón de sutura interrumpida. Suturas sintéticas no absorbibles se pueden utilizar en lugar de la seda para suturar la piel. </li><li> Retire la cánula traqueal de la rata se vuelve a establecer la respiración espontánea de una vez. </li><li> Cierre la abertura de la tráquea con 3,0 puntos de sutura de prolene y la capa de la piel con 4,0 puntos de seda. </li><li> Permita que el animal se recupere en tque el calentamiento de la almohadilla mediante la reducción gradual de la anestesia y ventilación respiración asistida. </li><li> En los animales de control simulado de la misma edad, realizar la traqueotomía y la toracotomía y sin constricción de la aorta ascendente. </li></ol> 5) Cuidado post-operatorio <ol><li> Desinfectar el área quirúrgica con solución de povidona yodada. </li><li> Como analgesia postoperatoria, inyecte tramadol por vía intraperitoneal (10 mg / kg de peso corporal / día) durante 1 semana. </li><li> Inyectar estéril salina normal por vía intraperitoneal si aparecen signos de deshidratación después de la cirugía (aproximadamente 1 ml). </li><li> Administrar amoxicilina por vía oral, mezclado con el agua potable, durante siete días (dosis: 500 mg / L de agua). </li><li> Elimine cualquier resto de suturas de seda de la piel después de 10 días de la cirugía bajo anestesia por inhalación. </li></ol> 6) Confirmación de constricción con éxito de aorta ascendente <ol><li> Realice una transtorácica bidimensional ecocardiografía Doppler para determinar la intenciónsidad de la sobrecarga de presión producida por la constricción de la aorta ascendente. </li><li> Se anestesia a las ratas una semana después de la cirugía como se describe anteriormente (paso 1.5) </li><li> Coloque el transductor de ultrasonido en la posición esternal supra para registrar el gradiente de presión a través de la parte de constricción de la aorta ascendente. Nota: Las ratas con un gradiente de presión de aproximadamente 60 mm de Hg en el sitio restringido aórtica desarrollarán hipertrofia cardíaca severa por cerca de 8-10 semanas después de la cirugía. </li></ol>

<ol>
	<li>Patten, R. D., Hall-Porter, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Small+animal+models+of+heart+failure:+development+of+novel+therapies,+past+and+present.">Small animal models of heart failure: development of novel therapies, past and present.</a> Circ Heart Fail. 2, 138-144 (2009).</li><li>Weinberg, E. O., 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=Angiotensin-converting+enzyme+inhibition+prolongs+survival+and+modifies+the+transition+to+heart+failure+in+rats+with+pressure+overload+hypertrophy+due+to+ascending+aortic+stenosis.">Angiotensin-converting enzyme inhibition prolongs survival and modifies the transition to heart failure in rats with pressure overload hypertrophy due to ascending aortic stenosis.</a> Circulation. 90, 1410-1422 (1994).</li><li>Schunkert, H., 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=Increased+rat+cardiac+angiotensin+converting+enzyme+activity+and+mRNA+expression+in+pressure+overload+left+ventricular+hypertrophy.+Effects+on+coronary+resistance,+contractility,+and+relaxation.">Increased rat cardiac angiotensin converting enzyme activity and mRNA expression in pressure overload left ventricular hypertrophy. Effects on coronary resistance, contractility, and relaxation.</a> J Clin Invest. 86, 1913-1920 (1990).</li><li>Hasenfuss, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+models+of+human+cardiovascular+disease,+heart+failure+and+hypertrophy.">Animal models of human cardiovascular disease, heart failure and hypertrophy.</a> Cardiovasc Res. 39, 60-76 (1998).</li><li>Litwin, S. E., 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=Serial+echocardiographic-Doppler+assessment+of+left+ventricular+geometry+and+function+in+rats+with+pressure-overload+hypertrophy.+Chronic+angiotensin-converting+enzyme+inhibition+attenuates+the+transition+to+heart+failure.">Serial echocardiographic-Doppler assessment of left ventricular geometry and function in rats with pressure-overload hypertrophy. Chronic angiotensin-converting enzyme inhibition attenuates the transition to heart failure.</a> Circulation. 91, 2642-2654 (1995).</li><li>Miyamoto, M. 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=Adenoviral+gene+transfer+of+SERCA2a+improves+left-ventricular+function+in+aortic-banded+rats+in+transition+to+heart+failure.">Adenoviral gene transfer of SERCA2a improves left-ventricular function in aortic-banded rats in transition to heart failure.</a> Proc Natl Acad Sci U S A. 97, 793-798 (2000).</li><li>Kagaya, Y., Hajjar, R. J., Gwathmey, J. K., Barry, W. H., Lorell, B. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-term+angiotensin-converting+enzyme+inhibition+with+fosinopril+improves+depressed+responsiveness+to+Ca2++in+myocytes+from+aortic-banded+rats.">Long-term angiotensin-converting enzyme inhibition with fosinopril improves depressed responsiveness to Ca2+ in myocytes from aortic-banded rats.</a> Circulation. 94, 2915-2922 (1996).</li><li>Del Monte, F., Butler, K., Boecker, W., Gwathmey, J. K., Hajjar, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+technique+of+aortic+banding+followed+by+gene+transfer+during+hypertrophy+and+heart+failure.">Novel technique of aortic banding followed by gene transfer during hypertrophy and heart failure.</a> Physiol Genomics. 9, 49-56 (2002).</li><li>Turcani, M., Rupp, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heart+failure+development+in+rats+with+ascending+aortic+constriction+and+angiotensin-converting+enzyme+inhibition.">Heart failure development in rats with ascending aortic constriction and angiotensin-converting enzyme inhibition.</a> Br J Pharmacol. 130, 1671-1677 (2000).</li><li>Kerem, 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=Lung+endothelial+dysfunction+in+congestive+heart+failure:+role+of+impaired+Ca2++signaling+and+cytoskeletal+reorganization.">Lung endothelial dysfunction in congestive heart failure: role of impaired Ca2+ signaling and cytoskeletal reorganization.</a> Circ Res. 106, 1103-1116 (2010).</li><li>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></ol>

Los autores no tienen nada que revelar.

Hay varios modelos quirúrgicos para la inducción de la sobrecarga de presión, así como la hipertrofia cardíaca y la insuficiencia cardíaca. En pequeños animales, Lorell y sus colegas desarrollaron el modelo que hemos descrito aquí y reportaron la ocurrencia de hipertrofia cardiaca compensada 8 semanas después aórtica 5. Cambios cardíacos avancen paulatinamente hacia un estado descompensada y luego dan lugar a la insuficiencia cardíaca. La principal ventaja de este modelo es la aparición gradual d...

Pequeños modelos animales son los instrumentos preferidos para el estudio de los cambios crónicos en el desarrollo de hipertrofia cardiaca y su progresión a la insuficiencia cardíaca. Modelos de insuficiencia cardíaca por métodos quirúrgicos fueron desarrollados originalmente en ratas ya que estos animales son los más adecuados para los procedimientos quirúrgicos del pecho abierto, la ecocardiografía y la evaluación de los parámetros hemodinámicos. También proporcionan muestras post mortem adecuados para estudios de nivel 1 moleculares del tejido, celular y. La constricción de la aorta ascendente es uno de los modelos quirúrgicos más comunes y exitosos para la creación de la sobrecarga de presión insuficiencia cardíaca 2, 3. Este modelo es muy adecuado para estudiar los eventos de remodelación celular celulares y sub y las propiedades contráctiles del corazón durante la transición de hipertrofia a la insuficiencia cardiaca 4. Una ventaja importante de este modelo es la aparición gradual de la sobrecarga de presión sobre el corazón 5, &lt;/ Sup&gt; 6. Este modelo es clínicamente relevante debido a su lenta pero constante progresión de la hipertrofia cardiaca compensada a la fase descompensada y finalmente a la etapa de la insuficiencia cardíaca. La duración para la progresión de la hipertrofia cardíaca a la insuficiencia cardíaca y los cambios fisiológicos asociados están influenciados principalmente por el grado de estenosis producido 7. Ascendente constricción de la aorta se puede realizar de dos maneras, ya sea mediante el uso de suturas o por aplicación de clips metálicos 8, 9. La principal ventaja de utilizar un clip metálico para constricción de la aorta es que los procedimientos quirúrgicos son menos complicados. En este método se tiene que localizar la aorta ascendente supra valvular e inserte la pinza alrededor de la aorta para obtener el nivel deseado de constricción. Un retractor de pecho no es necesario en este procedimiento. Aórtica mediante sutura requiere manipulaciones más quirúrgicas para la colocación de la aguja de calibre al lado de la aorta ascendente y la sutura alrededor de ella paraproducir el nivel deseado de constricción de la aorta. La última técnica es más lento en comparación con el uso de clips metálicos para la constricción de la aorta. El método descrito en este video demuestra el procedimiento quirúrgico para la constricción de la aorta ascendente en ratas que permite la creación de presión modelo de hipertrofia ventricular izquierda sobrecargado.

<table border="0" cellpadding="0" cellspacing="0" width="742">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Wistar rats</td>
			<td style="width:149px;"></td>
			<td style="width:119px;"></td>
			<td style="width:220px;">Maintained at ARF, RGCB</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Inhalation anaesthesia systems&#160;</td>
			<td style="width:149px;">VetEquip</td>
			<td style="width:119px;">AB19276</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Rodent ventilator</td>
			<td style="width:149px;">CWE Inc</td>
			<td style="width:119px;">SAR- 830/AP&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Rat tracheal cannula</td>
			<td style="width:149px;">CWE Inc</td>
			<td style="width:119px;">13-21032</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Ultrasound system</td>
			<td style="width:149px;">Philips</td>
			<td style="width:119px;">HD7</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Ultrasound transducer</td>
			<td style="width:149px;">Philips</td>
			<td style="width:119px;">S 12</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Titanium clip (small)</td>
			<td style="width:149px;">Horizon</td>
			<td style="width:119px;">1204</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Clip applicator</td>
			<td style="width:149px;">Weck</td>
			<td style="width:119px;">137081</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Electric shaver</td>
			<td style="width:149px;">Vinverth</td>
			<td style="width:119px;">VBT0817</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">BP blade (size:11)</td>
			<td style="width:149px;">Surgeon</td>
			<td style="width:119px;">REF10111</td>
			<td>Preparation of surgical site</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Tramadol</td>
			<td style="width:149px;">Orchid health care</td>
			<td style="width:119px;">OCH043</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Amoxycillin Hydrochloride</td>
			<td style="width:149px;">Ranbaxy</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Isoflurane</td>
			<td style="width:149px;">Piramal health care</td>
			<td style="width:119px;">A23M10A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Syringes</td>
			<td style="width:149px;">BD</td>
			<td style="width:119px;">2015-09</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">4-0 braided silk</td>
			<td style="width:149px;">Diamond</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">3-0 prolene</td>
			<td style="width:149px;">Johnson&#38;Johnson</td>
			<td style="width:119px;">NW018</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Surgical tape</td>
			<td style="width:149px;">Romsons</td>
			<td style="width:119px;">SH 6301</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Povidone iodine</td>
			<td style="width:149px;">Win Medicare</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Temp. controlled heating pad</td>
			<td style="width:149px;">Flamingo</td>
			<td style="width:119px;">HC1003</td>
			<td></td>
		</tr>
	</tbody>
</table>

ascending aortic constriction in rats for creation of pressure overload cardiac hypertrophy model

Ascendente constricción de la aorta es el modelo quirúrgico más común y exitoso para la creación de la sobrecarga de presión inducida por la hipertrofia cardíaca y la insuficiencia cardíaca. Aquí se describe un procedimiento quirúrgico detallado para la creación de la sobrecarga de presión e hipertrofia cardiaca en ratas mediante la constricción de la aorta ascendente mediante un pequeño clip metálico. Después de la anestesia, la tráquea se intuba mediante la inserción de una cánula a través de una incisión media manera hecha entre dos anillos de cartílago de la tráquea. A continuación, una incisión en la piel se hace a nivel del segundo espacio intercostal en la pared torácica izquierda y capas musculares se borran hasta encontrar la parte ascendente de la aorta. La aorta ascendente se estrecha a 50-60% de su diámetro original mediante la aplicación de un pequeño clip de titanio de tamaño. Después de constricción de la aorta, las segunda y tercera costillas son aproximadas con suturas de prolene. Se restableció Se retira la cánula traqueal respiración espontánea una vez. Se deja que el animal pueda recuperarse On el cojín de calefacción mediante la reducción gradual de la anestesia. La intensidad de la sobrecarga de presión creada por la constricción de la aorta ascendente se determina mediante el registro de la gradiente de presión utilizando transtorácica bidimensional ecocardiografía Doppler. En general, este protocolo es útil para estudiar los eventos de remodelación y las propiedades contráctiles del corazón durante la aparición gradual y la progresión de la hipertrofia cardiaca compensada a la etapa de la insuficiencia cardíaca.

En nuestros experimentos podemos lograr más del 80% las tasas de supervivencia. La eficacia de la constricción de la aorta fue confirmada mediante la realización de ecocardiografía Doppler. Las ratas (n = 6) con un gradiente de presión de aproximadamente 60 mm de Hg en el sitio de constricción aórtica se observaron durante 8 semanas y se sacrificaron a analizar para el desarrollo de la hipertrofia cardíaca (Figura 1). Después de 8 semanas de evaluación ecocardiográfica después de la cirugía...

Watch this Scientific Journal Video about Ascending Aortic Constriction in Rats for Creation of Pressure Overload Cardiac Hypertrophy Model at JoVE.com

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

Se describe un procedimiento paso a paso para la creación de la sobrecarga de presión e hipertrofia del ventrículo izquierdo en ratas Wistar por la constricción de la aorta ascendente mediante un pequeño clip metálico. Este modelo se utiliza ampliamente para el estudio de los cambios de remodelación durante la hipertrofia cardíaca y para la identificación y evaluación de las estrategias para la regresión de dichos cambios.

Ascendente aórtica Constricción en ratas para la Creación de la sobrecarga de presión hipertrofia cardíaca Modelo

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

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17.0K vistas.  Rajiv Gandhi Centre for Biotechnology.  Se describe un procedimiento paso a paso para la creación de la sobrecarga de presión e hipertrofia del ventrículo izquierdo en ratas Wistar por la constricción de la aorta ascendente mediante un pequeño clip metálico. Este modelo se utiliza ampliamente para el estudio de los cambios de remodelación durante la hipertrofia cardíaca y para la identificación y evaluación de las estrategias para la regresión de dichos cambios. 

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

Ultrasound Based Assessment of Coronary Artery Flow and Coronary Flow Reserve Using the Pressure Overload Model in Mice

Transthoracic Doppler echocardiography (TTDE) is a clinically useful, noninvasive tool for studying coronary artery flow velocity and coronary flow reserve (CFR) in humans. Reduced CFR is accompanied by marked intramyocardial and pericoronary fibrosis and is used as an indication of the severity of dysfunction. This study explores, step-by-step, the real-time changes measured in the coronary flow velocity, CFR and systolic to diastolic peak velocity (S/D) ratio in the setting of an aortic banding model in mice. By using a Doppler transthoracic imaging technique that yields reproducible and reliable data, the method assesses changes in flow in the septal coronary artery (SCA), for a period of over two weeks in mice, that previously either underwent aortic banding or thoracotomy. 
During imaging, hyperemia in all mice was induced by isoflurane, an anesthetic that increased coronary flow velocity when compared with resting flow. All images were acquired by a single imager. Two ratios, (1) CFR, the ratio between hyperemic and baseline flow velocities, and (2) systolic (S) to diastolic (D) flow were determined, using a proprietary software and by two independent observers. Importantly, the observed changes in coronary flow preceded LV dysfunction as evidenced by normal LV mass and fractional shortening (FS). 
The method was benchmarked against the current gold standard of coronary assessment, histopathology. The latter technique showed clear pathologic changes in the coronary artery in the form of peri-coronary fibrosis that correlated to the flow changes as assessed by echocardiography. 
The study underscores the value of using a non-invasive technique to monitor coronary circulation in mouse hearts. The method minimizes redundant use of research animals and demonstrates that advanced ultrasound-based indices, such as CFR and S/D ratios, can serve as viable diagnostic tools in a variety of investigational protocols including drug studies and the study of genetically modified strains.

Coronary flow reserve (CFR) is useful for assessment of myocardial oxygen demand and evaluation of cardiovascular risk. This study establishes a step-by-step transthoracic Doppler echocardiographic (TTDE) method for longitudinal monitoring of the changes in CFR, as measured from coronary artery in mice, under the experimental pressure overload of aortic banding.

Evaluación Ultrasonido base de la arteria coronaria de flujo y la reserva coronaria Utilizando la sobrecarga Modelo Presión en ratones

Transthoracic Doppler echocardiography (TTDE) is a clinically useful, noninvasive tool for studying coronary artery flow velocity and coronary flow ...

Investigación

Medicina

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.

Evaluación de la cardíaco morfológica y funcional Los cambios en el modelo de ratón de la constricción de la aorta transversa por ecocardiográfico 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 ...

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.

Un modelo de remodelamiento cardiaco A través de la constricción de la aorta abdominal en ratas

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.

La constricción aórtica mínimamente invasiva transversal en ratones

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.

Técnica mínimamente invasiva constricción aórtica transversal en ratones para la inducción de la hipertrofia Ventricular izquierda

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.

Un modelo del cerrado-pecho para inducir constricción aórtica transversal en ratones

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

A Pulmonary Trunk Banding Model of Pressure Overload Induced Right Ventricular Hypertrophy and Failure

Right ventricular (RV) failure induced by sustained pressure overload is a major contributor to morbidity and mortality in several cardiopulmonary disorders. Reliable and reproducible animal models of RV failure are therefore warranted in order to investigate disease mechanisms and effects of potential therapeutic strategies. Banding of the pulmonary trunk is a common method to induce isolated RV hypertrophy but in general, previously described models have not succeeded in creating a stable model of RV hypertrophy and failure.
We present a rat model of pressure overload induced RV hypertrophy caused by pulmonary trunk banding (PTB) that enables different phenotypes of RV hypertrophy with and without RV failure. We use a modified ligating clip applier to compress a titanium clip around the pulmonary trunk to a pre-set inner diameter. We use different clip diameters to induce different stages of disease progression from mild RV hypertrophy to decompensated RV failure.
RV hypertrophy develops consistently in rats subjected to the PTB procedure and depending on the diameter of the applied banding clip, we can accurately reproduce different disease severities ranging from compensated hypertrophy to severe decompensated RV failure with extra-cardiac manifestations.
The presented PTB model is a valid and robust model of pressure overload induced RV hypertrophy and failure that has several advantages to other banding models including high reproducibility and the possibility of inducing severe and decompensated RV failure.

We present a surgical method to induce right ventricular hypertrophy and failure in rats.

Un tronco pulmonar las bandas modelo de sobrecarga de presión inducida por el fracaso y la hipertrofia Ventricular derecha

Right ventricular (RV) failure induced by sustained pressure overload is a major contributor to morbidity and mortality in several cardiopulmonary ...

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.

Operación de constricción aórtica transversal con sutura absorbible para obtener hipertrofia miocárdica transitoria

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

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.

Banda aórtica con junta tórica versus constricción aórtica transversal tradicional para el modelado de la hipertrofia cardíaca inducida por sobrecarga de presión

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

Modified Heterotopic Abdominal Heart Transplantation and a Novel Aortic Regurgitation Model in Rats

Over the past 50 years, many researchers have reported heterotopic abdominal heart transplantation in mice and rats, with some variations in the surgical technique. Modifying the transplantation procedure to strengthen the myocardial protection could prolong the ischemia time while preserving the donor&#39;s cardiac function. This technique&#39;s key points are as follows: transecting the donor&#39;s abdominal aorta before harvesting to unload the donor&#39;s heart; perfusing the donor&#39;s coronary arteries with a cold cardioplegic solution; and topical cooling of the donor&#39;s heart during the anastomosis procedure. Consequently, since this procedure prolongs the acceptable ischemia time, beginners can easily perform it and achieve a high success rate.
Moreover, a new aortic regurgitation (AR) model was established in this work using a technique different from the existing one,&#160;which is created by inserting a catheter from the right carotid artery and puncturing the native aortic valve under continuous echocardiographic guidance. A heterotopic abdominal heart transplantation was performed using the novel AR model. In the protocol, after the donor&#39;s heart is harvested, a stiff guidewire is inserted into the donor&#39;s brachiocephalic artery and advanced toward the aortic root. The aortic valve is punctured by pushing the guidewire further even after the resistance is felt, thus inducing AR. It is easier to damage the aortic valve using this method than with the procedure described in the conventional AR model. Additionally, this novel AR model does not contribute to the recipient&#39;s circulation; therefore, this method is expected to produce a more severe AR model than the conventional procedure.

This study demonstrates a reproducible heterotopic abdominal heart transplantation technique in rats that beginners can learn and perform. Additionally, a novel aortic regurgitation model in rats is generated by performing heterotopic abdominal heart transplantation and damaging the donor's aortic valve using a guidewire after harvesting.

Trasplante de corazón abdominal heterotópico modificado y un nuevo modelo de regurgitación aórtica en ratas

Over the past 50 years, many researchers have reported heterotopic abdominal heart transplantation in mice and rats, with some variations in the surgical ...