著者らは、このプロジェクトの財政支援のためのバイオテクノロジー本部、インド政府を認める。 AjithクマーGSは医学研究、インド政府のインド評議会の上級研究フェローシップと科学産業研究評議会、インド、Binilラジ政府の上級研究フェローシップでサポートされていました。

動物実験は、動物実験倫理委員会の承認を得た後に実施された。 Wistar系ラットを明サイクル、（CPCSEAガイドラインに従って）食物と水を自由に一定の室温（24±2℃）に12時間の暗闇の下で飼育した。 1）術前ケアと麻酔<ol><li> （水の500 mg / Lの用量）を経口アモキシシリンを投与することによって、手術前の抗生物質の傘の下で24時間ラット（約200gの体重）を保つ。 </li><li> 15分間121℃でオートクレーブ処理することによって（例えば、ハサミ、鉗子、クリップアプリケータ、縫合針、および針ホルダのような）すべての手術器具を滅菌する。 </li><li>心拍数の急激な低下を避けるために37°Cの周囲に動物の体温を維持するために、加熱パッドを使用する。 </li><li>手術前との間に動物の脱水を避けるために注意してください。 </li><li>と混合し、3％イソフルランで誘導チャンバー内のラットを麻酔0.5-1.0 L /分の酸素100％; 1.5％イソフルランで麻酔を維持。 </li><li>成功した麻酔を確認するために、ペダル反射を確認してください。 </li></ol>手術部位の2）の準備<ol><li>仰臥位で温度制御された加熱パッドの上にラットを保管してください。 </li><li>ノーズコーンで麻酔を維持したままの位置に動物を維持するために、ラットの前歯の上にゴムバンドを配置します。 </li><li> （好ましくは、電気シェーバーを使用する）は、ラットのネックラインと左胸領域から毛を削除します。 </li><li>ポビドンヨード溶液で手術部位を消毒した後、70％エチルアルコールで。 </li><li>手術手順の間だけ、手術部位を露出させ、滅菌ドレープを使用しています。 注意：動物のケアのための追加オプションとして、0.25％ブピバカインID（2.5 mg / kgのは）前に局所麻酔/鎮痛のため、各切開部位切開に組み込むことができる。 </li></ol>ラットにおける3）気管挿管<ol><li>無菌手術用ブレードを用いて気管に皮膚と平行に小さな切開を行い、慎重に気管を露出させるために、基礎となる組織を分離。 </li><li>気管の下に4-0絹縫合糸のネクタイをつけて軽く上向きのネクタイを上げる。 </li><li> 2軟骨輪の中間に切開を行い、ラットの気管に気管カニューレを挿入します。 </li><li> 50呼吸/分、（200グラム体重ラット用）0.60秒1.70ミリリットルと吸気時間の一回換気量の呼吸数を維持するための齧歯類の人工呼吸器に気管カニューレを接続します。 </li></ol>昇順大動脈の4）くびれ<ol><li>指でのリブの位置を感知した後、第二及び第三肋骨の間の左胸の壁に約2cmの皮膚切開を行う。 </li><li>層で肋間筋層を分離し第2及び第3肋骨の間、約1.5センチの切開を行います。 （ケア取るでなければなりません肋骨の間を切開しながら、肺への傷害を避けるために、N） </li><li>リブを撤回し、大動脈の上昇部分を探します。 </li><li>元の直径の50〜60％までの大動脈を収縮することにより、アプリケータの助けを借りて、上行大動脈の周囲に小型のチタンクリップを配置します。 </li><li>大動脈狭窄後、中断された縫合パターンで3.0プロレンと第二と第三のリブに近似している。同時に、肺を再膨張させるために、約2〜4秒間ベンチレータを一時停止する。 </li><li> 3.0プロレン縫合および結節縫合パターンの4.0絹縫合糸で皮膚と筋肉層を並置。合成非吸収性縫合糸で皮膚を縫合するための代わりのシルクを使用することができる。 </li><li>ラット一度自発呼吸から気管カニューレを取り外し再確立である。 </li><li> 3.0プロレン縫合および4.0絹縫合糸で皮膚層を気管開口部を閉じる。 </li><li>動物はTに回復することができ彼は徐々に麻酔と人工呼吸補助呼吸を低下させることにより、パッドを加熱する。 </li><li>年齢をマッチさせた偽対照動物では、上行大動脈の狭窄せずに気管切開や開胸を行う。 </li></ol> 5）術後ケア<ol><li>ポビドンヨード液で手術領域を消毒。 </li><li>術後鎮痛ように、1週間（10 mg / kg体重/日）トラマドール腹腔内注入する。 </li><li>脱水の兆候が手術（約1ミリリットル）の後に表示される場合は、無菌生理食塩水を腹腔内に注射する。 </li><li> （：水500 mg / Lの用量）7日間、経口飲料水と混合アモキシシリンを管理します。 </li><li>吸入麻酔下での手術の10日後に皮膚から残りの絹縫合糸を取り除く。 </li></ol>昇順大動脈の成功くびれ6）の確認<ol><li> INTENを決定するために、経胸腔2次元ドップラー心エコー検査を行う上行大動脈の収縮による圧力過負荷のsity。 </li><li>先に述べたように、ラットを1週間の手術後の麻酔（ステップ1.5） </li><li>上行大動脈の狭窄部を横切る圧力勾配を記録するために前出胸骨の位置に超音波振動子を配置します。 注意：大動脈くびれサイトで水銀の約60ミリメートルの圧力勾配を持つラットは約8〜10週間で重度の心臓肥大を開発する手術を投稿してください。 </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>

著者らは、開示することは何もありません。

圧負荷の誘導ならびに心肥大および心不全のためのいくつかの外科的モデルがある。小動物では、Lorellらは我々がここで説明したモデルを開発し、彼らが補償心肥大8週間後の大動脈結紮5が発生したことを報告した。心臓の変化は徐々に非代償性状態に進行した後、心不全につながる。このモデルの主な利点は、左心室圧の増加および慢性高血圧の臨床状況に類似し、従ってを徐々に...

小動物モデルは、心肥大および心不全への進行の発展における慢性変化の研究のための最も好ましい手段である。これらの動物は、開胸外科的処置、心エコー検査および血行力学パラメータの評価に最も適しているように、外科的方法による心不全のラットモデルは、もともと開発された。彼らはまた、組織、細胞および分子レベルでの研究1で十分死後サンプルを提供。上行大動脈の狭窄は、圧負荷心不全2、3を作成するための最も一般的かつ成功した外科的モデルの一つである。このモデルは、肥大から心不全への移行中4細胞の細胞リモデリングおよびサブイベントや心臓の収縮特性を研究するのに適している。 このモデルの主な利点は、心臓5上の圧負荷を徐々に発症は&lt;/ SUP&gt; 6。このモデルは、理由に補償心肥大から非代償期へ、そして最後に心不全の段階へゆっくりだが着実に進行の臨床的に関連している。心不全と関連する生理学的変化に対する心臓肥大の進行の持続時間は、主に7を生成した狭窄の程度によって影響される。上行大動脈狭窄は、縫合糸を使用することによって又は金属クリップ8,9のアプリケーションのいずれかによって、二つの方法で行うことができる。大動脈狭窄のための金属製のクリップを使用することの主な利点は、外科的処置がより複雑であることである。この方法では、1は、前出の弁膜上行大動脈を見つけて、くびれの所望のレベルを得るために、大動脈の周りにクリップを挿入しなければならない。胸のトラクターは、この手順は必要ありません。縫合による大動脈結紮は、上行大動脈の横にゲージの針を配置し、それを中心に縫合するためのより多くの外科的操作を必要とする大動脈狭窄の所望のレベルを生成する。後者の技術は、大動脈狭窄用金属クリップを用いた場合に比べ、より多くの時間がかかる。このビデオで説明した方法は、作成圧のオーバーロードされた左心室肥大モデルを可能にする、ラットにおける大動脈狭窄を昇順、外科的処置を示しています。

<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

大動脈狭窄昇順ことは心肥大および心不全を誘発した圧負荷を作成するための最も一般的で成功した外科的なモデルです。ここでは、小さな金属クリップを用いて上行大動脈の狭窄によってラットにおいて圧負荷心肥大を作成するための詳細な外科的処置を記載している。麻酔後、気管切開気管の2軟骨輪間で半分の方法を通じてカニューレを挿入することにより、挿管されている。次いで、皮膚切開は、左胸壁上の第2肋間腔のレベルで行われ、筋層を大動脈の上昇部分を見つけるためにクリアされる。上行大動脈は、小型のチタンクリップを適用することによって、元の直径の50〜60％まで収縮している。大動脈狭窄後に、第二および第三リブはプロレン縫合糸で近似される。気管カニューレが除去され、一度自発呼吸が再確立された。動物は、Oを回復させる徐々に麻酔を低下させることにより、加熱パッドをn個。上行大動脈の狭窄によって生じる圧力負荷の強度は、経胸腔二次元ドップラー心エコー検査を用いて圧力勾配を記録することによって決定される。全体的に、このプロトコルは、心不全期に補償心肥大から徐々に発症し、進行の間に改造イベントや心臓の収縮特性を研究することは有用である。

我々の実験では、80％以上の生存率を達成することができる。大動脈狭窄の有効性は、ドップラー心エコー検査を行うことによって確認された。大動脈狭窄部位でのHg約60mmの圧力勾配を有するラット（n = 6）は、8週間観察し、心臓肥大（ 図1）の開発のために分析するために屠殺した。 8週間後、手術後の心エコー評価は、偽手術と比較して、そのような大動脈狭窄を受けた動物?...

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

我々は、小さな金属クリップを用いて上行大動脈の狭窄によってWistarラットにおける圧負荷及び左心室肥大を作成するための段階的な手順を記載している。このモデルは、広範囲に心肥大中にリモデリングの変化を研究するためのそのような変更の退行ための戦略を同定および評価するために使用される。

圧負荷心肥大モデルの作成のためのラットの大動脈狭窄昇順

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

ascending-aortic-constriction-rats-for-creation-pressure-overload

Research

JoVE Journal

Medicine

17.0K ビュー.  Rajiv Gandhi Centre for Biotechnology. 我々は、小さな金属クリップを用いて上行大動脈の狭窄によってWistarラットにおける圧負荷及び左心室肥大を作成するための段階的な手順を記載している。このモデルは、広範囲に心肥大中にリモデリングの変化を研究するためのそのような変更の退行ための戦略を同定および評価するために使用される。 

ビデオ: 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.

マウスの圧負荷モデルを用いた冠動脈の流れと冠血流準備の超音波ベースのアセスメント

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

医学

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.

心臓形態学的および心エコーイメージングによって横大動脈狭窄のマウスモデルにおける機能の変更の評価

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.

ラットの腹部大動脈の収縮を通じて心臓リモデリングのモデル

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.

マウスにおける低侵襲横大動脈狭窄

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.

左室肥大の誘導マウスにおける低侵襲の横大動脈狭窄のテクニック

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.

マウスで横方向の大動脈狭窄を誘導するために閉じて胸モデル

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.

肺動脈バンディング圧負荷のモデルによる右室肥大と失敗

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.

過渡性心筋肥大を得るために吸収性縫合を用いて横方向の大動脈収縮を操作する

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.

圧力過負荷誘発心肥大をモデル化するためのOリング大動脈バンディングと従来の横大動脈狭窄の比較

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.

ラットにおける修正異所性腹部心臓移植と新規大動脈閉鎖不全症モデル

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