Les auteurs reconnaissent Département de biotechnologie, gouvernement de l&#39;Inde pour le soutien financier de ce projet. Ajith Kumar GS a été pris en charge avec bourse de recherche principal du Conseil de recherche scientifique et industrielle, gouvernement de l&#39;Inde et Binil Raj avec bourse de recherche principal du Conseil indien de la recherche médicale, gouvernement de l&#39;Inde.

Les expérimentations animales ont été effectuées après l&#39;obtention de l&#39;approbation du Comité d&#39;éthique animale institutionnel. Des rats Wistar ont été logés dans une obscurité de 12 h à cycle de lumière, température ambiante constante (24 ± 2 ° C) avec de la nourriture et de l&#39;eau ad libitum (selon les lignes directrices de CPCSEA). 1) Soins pré-opératoire et anesthésie <ol><li> Gardez rat (environ 200 g de poids corporel) sous antibiotique parapluie 24 heures avant une intervention chirurgicale par l&#39;administration d&#39;amoxicilline par voie orale (dose: 500 mg / L d&#39;eau). </li><li> Stériliser tous les instruments chirurgicaux (tels que ciseaux, pinces, d&#39;agrafes, aiguilles de suture, et porte-aiguille) par autoclavage à 121 ° C pendant 15 min. </li><li> Utiliser un coussin chauffant pour maintenir la température du corps de l&#39;animal autour de 37 ° C pour éviter une rapide diminution de la fréquence cardiaque. </li><li> Prenez soin d&#39;éviter la déshydratation de l&#39;animal avant et pendant la chirurgie. </li><li> Anesthésier le rat dans une chambre d&#39;induction avec 3% d&#39;isoflurane mélangé avec0,5-1,0 L / min de 100% d&#39;oxygène; maintenir l&#39;anesthésie avec 1,5% d&#39;isoflurane. </li><li> Vérifiez le réflexe de pédale pour confirmer l&#39;anesthésie réussie. </li></ol> 2) Préparation du site opératoire <ol><li> Maintenir le rat sur le dessus d&#39;un coussin chauffant à température contrôlée dans la position couchée sur le dos. </li><li> Positionner une bande de caoutchouc sur les dents de devant du rat afin de maintenir l&#39;animal en position, tout en maintenant une anesthésie avec un cône de nez. </li><li> Enlever la fourrure de l&#39;encolure et à gauche la région thoracique du rat (de préférence en utilisant un rasoir électrique). </li><li> Désinfecter site chirurgical avec une solution de povidone-iode et ensuite avec de l&#39;alcool éthylique à 70%. </li><li> Utilisez un champ stérile pour exposer que le site chirurgical lors de l&#39;intervention. Remarque: Comme une option supplémentaire pour le soin des animaux, 0,25% bupivicaïne ID (2,5 mg / kg) peut être incorporé avant l&#39;incision à chaque site de l&#39;incision à l&#39;anesthésie locale / analgésie. </li></ol> 3) Intubation trachéale chez le rat <ol><li> Faire une petite incision sur la peau parallèlement à la trachée en utilisant une lame chirurgicale stérile et on sépare soigneusement le tissu sous-jacent afin d&#39;exposer la trachée. </li><li> Appliquer une cravate de soie 4-0 fil de suture sous la trachée et soulevez doucement le lien vers le haut. </li><li> Faire une incision en demi-chemin entre deux anneaux de cartilage et insérer la canule trachéale dans la trachée du rat. </li><li> Connectez la canule trachéale à un ventilateur de rongeur pour maintenir une fréquence respiratoire de 50 respirations / min, le volume de marée de 1,70 ml et temps de l&#39;inspiration de 0,60 s (rat avec 200 g de poids corporel). </li></ol> 4) La constriction de l&#39;aorte ascendante <ol><li> Après détection de la position des nervures avec les doigts, faire une incision de la peau d&#39;environ 2 cm sur la paroi gauche de la poitrine entre les deuxième et troisième nervures. </li><li> Séparer la couche de muscles intercostaux par couche et faire une incision d&#39;environ 1,5 cm de long entre les deuxième et troisième côtes. (Il faut être prendren d&#39;éviter toute blessure aux poumons tout en faisant une incision entre les côtes) </li><li> Rentrez les côtes et de localiser la partie ascendante de l&#39;aorte. </li><li> Placer une petite pince de titane de taille autour de l&#39;aorte ascendante avec l&#39;aide d&#39;un applicateur par lequel la constriction de l&#39;aorte 50 à 60% du diamètre d&#39;origine. </li><li> Suite à la constriction aortique, rapprochant les deuxième et troisième nervures avec 3,0 prolène dans un motif de fil de suture interrompue. En même temps, mettre en pause le ventilateur pendant environ 2-4 secondes pour regonfler les poumons. </li><li> Apposer les couches musculaires avec 3,0 sutures prolène et la peau avec 4,0 points de suture de soie dans un modèle de suture interrompue. Sutures absorbables synthétiques non peuvent être utilisés à la place de la soie pour suturer la peau. </li><li> Retirer canule trachéale chez le rat de la respiration spontanée, une fois est rétablie. </li><li> Fermez l&#39;ouverture de la trachée avec 3,0 sutures prolène et la couche de peau avec 4,0 points de suture de soie. </li><li> Laisser l&#39;animal à récupérer sur til coussin chauffant en abaissant progressivement l&#39;anesthésie et respirateur respiration assistée. </li><li> Chez les animaux témoins simulacre appariés pour l&#39;âge, effectuer une trachéotomie et une thoracotomie sans constriction de l&#39;aorte ascendante. </li></ol> 5) Soins post-opératoires <ol><li> Désinfecter zone chirurgicale avec une solution de povidone-iode. </li><li> Comme l&#39;analgésie post-opératoire, injecter tramadol intra-péritonéale (10 mg / kg de poids corporel / jour) pendant 1 semaine. </li><li> Injecter une solution saline normale stérile intra-péritonéale si des signes de déshydratation apparaissent après la chirurgie (environ 1 ml). </li><li> Administrer amoxicilline par voie orale, mélangé avec de l&#39;eau potable, pendant sept jours (dose: 500 mg / L d&#39;eau). </li><li> Retirez toutes les sutures de soie restants de la peau après 10 jours de la chirurgie sous anesthésie par inhalation. </li></ol> 6) Confirmation de constriction réussie de l&#39;aorte ascendante <ol><li> Effectuez une trans-thoracique en deux dimensions Doppler échocardiographie pour déterminer la intentionsité de la surcharge de pression produite par la constriction de l&#39;aorte ascendante. </li><li> Anesthésier les rats une semaine après la chirurgie, comme décrit précédemment (étape 1.5) </li><li> Placer le transducteur à ultrasons à la position sternale précité pour enregistrer le gradient de pression à travers la partie rétrécie de l&#39;aorte ascendante. Remarque: Les rats avec un gradient de pression d&#39;environ 60 mm de Hg sur le site rétrécie aortique vont développer une hypertrophie cardiaque sévère par environ 8-10 semaines après la chirurgie. </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>

Les auteurs n&#39;ont rien à révéler.

Il existe plusieurs modèles chirurgicales pour l&#39;induction d&#39;une surcharge de pression, ainsi que l&#39;hypertrophie cardiaque et l&#39;insuffisance cardiaque. Chez les petits animaux, Lorell et ses collègues ont développé le modèle que nous avons décrit ici et ils ont signalé l&#39;apparition de l&#39;hypertrophie cardiaque compensée 8 semaines après de baguage aortique 5. Modifications cardiaques passent progressivement à un état décompensée et aboutissent à l&#39;insuffisance cardiaqu...

Petits modèles animaux sont les outils les plus privilégiées pour l&#39;étude des changements chroniques dans le développement de l&#39;hypertrophie cardiaque et sa progression vers l&#39;insuffisance cardiaque. modèles d&#39;insuffisance cardiaque par des méthodes chirurgicales ont été initialement développées chez le rat que ces animaux sont les plus appropriés pour les interventions chirurgicales thoraciques ouverte, l&#39;échocardiographie et l&#39;évaluation des paramètres hémodynamiques. Ils fournissent également des échantillons adéquats post mortem des tissus, cellulaire et des études au niveau moléculaire 1. Rétrécissement de l&#39;aorte ascendante est l&#39;un des modèles chirurgicales les plus courantes et efficaces pour la création d&#39;insuffisance cardiaque de surcharge de pression 2, 3. Ce modèle est bien adapté pour étudier les événements de remodelage cellulaire cellulaires et sous et les propriétés contractiles du coeur pendant la transition de l&#39;hypertrophie de l&#39;insuffisance cardiaque 4. Un avantage important de ce modèle est l&#39;apparition progressive d&#39;une surcharge de pression sur le coeur 5, &lt;/ Sup&gt; 6. Ce modèle est cliniquement pertinente en raison de sa progression lente mais constante de l&#39;hypertrophie cardiaque compensée à la phase décompensée et enfin au stade de l&#39;insuffisance cardiaque. La durée de la progression de l&#39;hypertrophie cardiaque de l&#39;insuffisance cardiaque et les changements physiologiques associés sont principalement influencés par le degré de sténose produit 7. Croissant constriction aortique peut être réalisé de deux manières, soit en utilisant des sutures ou par application d&#39;agrafes métalliques 8, 9. Le principal avantage de l&#39;utilisation d&#39;un clip métallique pour une constriction aortique est que les procédures chirurgicales sont moins compliqués. Dans cette méthode, il faut localiser le supra valvulaire de l&#39;aorte ascendante et insérer le clip autour de l&#39;aorte pour obtenir un niveau désiré de constriction. Enrouleur de poitrine n&#39;est pas nécessaire dans ce mode opératoire. Cerclage aortique par suture nécessite plusieurs manipulations chirurgicales pour placer l&#39;aiguille de l&#39;indicateur à côté de l&#39;aorte ascendante et de la suture autour d&#39;elle pourproduire le niveau de constriction aortique souhaitée. Cette dernière technique est plus longue en comparaison avec l&#39;utilisation de clips métalliques pour une constriction aortique. La méthode décrite dans cette vidéo montre la procédure chirurgicale pour ascendant constriction aortique chez les rats qui permet la création d&#39;une pression modèle de l&#39;hypertrophie ventriculaire gauche surchargé.

<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

Croissant rétrécissement aortique est le modèle chirurgicale la plus courante et efficace pour créer une surcharge de pression induite par l&#39;hypertrophie cardiaque et l&#39;insuffisance cardiaque. Ici, nous décrivons un procédé chirurgical détaillée pour créer une surcharge de pression et de l&#39;hypertrophie cardiaque chez les rats par constriction de l&#39;aorte ascendante en utilisant une petite pince métallique. Après l&#39;anesthésie, la trachée est intubée par l&#39;insertion d&#39;une canule à travers une incision à mi-chemin entre deux anneaux faits de cartilage de la trachée. Puis une incision de la peau est effectuée au niveau du deuxième espace intercostal sur la paroi de la poitrine gauche et les couches musculaires sont effacées pour localiser la partie ascendante de l&#39;aorte. L&#39;aorte ascendante est resserré à 50-60% de son diamètre initial par l&#39;application d&#39;un petit clip de titane de taille. Suite à une constriction aortique, les deuxième et troisième nervures sont estimés à l&#39;aide de sutures de prolène. La canule trachéale est retiré une fois que la respiration spontanée a été rétablie. L&#39;animal est autorisé à récupérer on le coussin chauffant en abaissant progressivement l&#39;anesthésie. L&#39;intensité de la surcharge de pression créée par constriction de l&#39;aorte ascendante est déterminé par l&#39;enregistrement du gradient de pression en utilisant transthoracique bidimensionnelle Doppler échocardiographie. Globalement, ce protocole est utile d&#39;étudier les événements de remodelage et les propriétés contractiles du coeur au cours de l&#39;installation progressive et de la progression de l&#39;hypertrophie cardiaque compensée à l&#39;étape de l&#39;insuffisance cardiaque.

Dans nos expériences, nous sommes en mesure d&#39;atteindre plus de 80% des taux de survie. L&#39;efficacité de constriction aortique a été confirmée par une échocardiographie Doppler. Les rats (n = 6) avec un gradient de pression d&#39;environ 60 mm de Hg à l&#39;endroit étranglé aortique ont été observés pendant 8 semaines et sacrifiés à analyser pour le développement de l&#39;hypertrophie cardiaque (figure 1). Après 8 semaines évaluation échocardiographique post-chirurgicale a rév?...

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

Nous décrivons un procédé par étapes pour la création d&#39;une surcharge de pression et de l&#39;hypertrophie ventriculaire gauche chez des rats Wistar par constriction de l&#39;aorte ascendante en utilisant une petite pince métallique. Ce modèle est largement utilisé pour étudier les changements de remodelage pendant l&#39;hypertrophie cardiaque et pour identifier et évaluer les stratégies pour la régression de ces changements.

Aortique ascendant constriction chez les rats pour la création de la surcharge de pression hypertrophie cardiaque Modèle

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 vues.  Rajiv Gandhi Centre for Biotechnology.  Nous décrivons un procédé par étapes pour la création d'une surcharge de pression et de l'hypertrophie ventriculaire gauche chez des rats Wistar par constriction de l'aorte ascendante en utilisant une petite pince métallique. Ce modèle est largement utilisé pour étudier les changements de remodelage pendant l'hypertrophie cardiaque et pour identifier et évaluer les stratégies pour la régression de ces changements. 

Vidéo: 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.

Évaluation Basé échographie de l&#39;artère coronaire de débit et de Flow Reserve coronaire Utilisation de la surcharge de pression modèle chez la souris

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

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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.

Évaluation des cardiaques morphologiques et fonctionnelles changements dans le modèle de souris de Transverse Aortic Constriction par échocardiographie 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 modèle de Cardiac Remodeling Grâce à constriction de l&#39;aorte abdominale chez les rats

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.

Minimalement invasive Transverse Aortic constriction chez la souris

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.

Technique mini-Invasive transversal constriction aortique chez les souris pour l’Induction de l’hypertrophie ventriculaire gauche

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 modèle à thorax fermé pour induire la Constriction de l’aorte transversale chez les souris

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.

Tronc pulmonaire des bandes modèle d’une surcharge de pression induit échec et hypertrophie ventriculaire droite

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.

Exploitation de la constriction aortique transversale avec suture absorbable pour obtenir une hypertrophie myocardique transitoire

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.

Anneaux toriques par rapport à la constriction aortique transversale traditionnelle pour la modélisation de l’hypertrophie cardiaque induite par surcharge de pression

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.

Transplantation cardiaque abdominale hétérotopique modifiée et nouveau modèle de régurgitation aortique chez le rat

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