この作品は、ドイツ学術協会（KFO 196」Signaltransduktion BEI adaptativenウントmaladaptiven kardialenかいそう-Prozessen」、FR 1638 / 1-2）でと心血管研究DZHK（ドイツ語センター、医療研究のドイツ語センターの一部でサポートされていました、BMBF（教育研究のドイツ省）構想）です。

注：単離手順の基本的なステップは、図1に示されているすべてのステップは、以下のプロトコルに詳細に記載されています。乳頭筋の分離、器官槽チャンバ内に取り付け、取得および分析は、連続し、強制タイムスケールで行われます。 全ての動物実験は、動物の保護に関するドイツの法律に従って行われ、ハイデルベルク大学の倫理審査委員会によって承認されました。 計装の調製<ol><li>収縮の測定ではmultichambered器官槽の設定を使用します。 エキソビボ収縮器官浴のセットアップの構成要素は、 図2に示されています。 注：乳頭筋の準備と実験プロトコルの開始との間の時間、セットアップ機器を最小限に抑え、実験tissue.Thisを集めるの提供しにバッファを前に準備するために組織は、実験を行うために生存し続ける時間の最大量をエス。 </li><li>コンピュータとデータ収集機器を起動します。臓器風呂熱（32°Cまでのプリセット）をオンにし、設定温度にユニットを可能にします。 </li><li>収集装置を準備します。ソフトウェアのマニュアルに記載されたように、データの記録を開始。 </li><li>チェックして、各チャンネルに（必要な場合）、キャリブレーションを実施し、認定重量により供給された2-Gの力に（そのチャネルに関連付けられている）は、それぞれの力変換器から供給される電気信号を標準化するために、すべてのチャネルをゼロに。 </li><li>器官槽室へのガス供給（95％O 2/5％CO 2）をオンにします。連続プロトコル全体の測定中に全てのチャンバをガス。 </li></ol>緩衝液および生理的溶液の調製<ol><li> 119 mMの塩化ナトリウムの最終濃度を達成するクレブス - ヘンゼライト緩衝液を調製します。 25mMの炭酸水素ナトリウム; 4.6のKCl; 11mmのグルコース; 1 mMののNa-Pyruvate; 1.5 mMのCaCl 2を、 1.64 mMのは、4硫酸マグネシウム; 1.18 mMのKH 2 PO 4、（ 表1生理溶液を参照）pHを7.4に調整します。 </li><li>追加の30mMの2,3-ブタンジオンモノオキシム（BDM）と50 IEヘパリン/ mlのステップ2.1で説明したように、分離中に使用する独立したクレブス - ヘンゼライト緩衝液を準備します。 4℃（表1調製液を参照）クールソリューション。表1に記載したように、虚血のシミュレーションでは、虚血溶液を調製。 </li><li> Ca 2+のプロトコルの場合-依存収縮、要求された最終濃度にクレブス-ヘンゼライト緩衝液にの Ca 2+ を追加します。 注：直接、その使用前に、これらの溶液を調製し、炭酸カルシウムの沈殿を避けるために、カルボゲンでGASS。使用する前に、32℃に予熱するソリューションを提供します。 </li></ol>乳頭切除手順の間に使用されるガス発生チューブと解剖皿の調製<ol><li>ソフトガスを接続します専門家の作業とガス接続（あるいは100％の酸素、カルボゲン）にチューブ（外径2〜4ミリメートル）を歌います。 </li><li>解剖皿の内側継手ガス発生管の閉じたリングを作成します。ガス発生管に連続発泡が保証されている数回穿刺。このガス放出管は、複数回使用することができます。 </li><li>ピンがそれに貼り付けることができるように、底部（0.5センチメートル厚）のシリコンエラストマーと解剖皿を準備します。この皿を数回使用することができます。 </li></ol>マウスの左前方乳頭筋の4.絶縁注：乳頭筋の分離を開始する前に、ガスラインが閉塞の明確であることを確認してください。 <ol><li>乳頭筋の準備を開始する前に、プロトコルセクション1-3で述べたように、臓器浴の設定を準備します。実験の日にすべてのソリューションを準備します。 </li><li>頸椎脱臼のaccordiによって（約8〜12週齢）のマウスを生け贄に捧げます専門家の作業と施設のガイドラインにNG。 </li><li>前足を固定して仰臥位で動物を修正し、解剖ボードに足を後肢、鋭い骨はさみで肋骨を切断することにより、両側の胸部の横を開いて、横方向のカットとダイアフラムを切りました。心膜を削除します。今心臓と大動脈をアクセス可能です。 </li><li>心臓に近い血管体幹の鈍ピンセットで心臓を修正して、肺と周囲の組織からハサミですぐに心を分離。 </li><li>酸素（ステップ2.2）にガスを供給した冷却調製液で満たされたペトリ皿に拍動している心臓を転送します。ハートビートとピンセットで心臓頂点に触れる介して、そっと心の収縮を刺激することを許可します。 </li><li>すぐに心臓が完全にexsanguinousで、冷却された調製液（ステップ2.2）を充填し、O 2ガスを供給解剖皿に移します。使用上のこのステップ実体顕微鏡から。 </li><li>ょんを修正心が背側から見られるように右心室を通って小さなピンとRT（右心室は、オペレータのビューから右側に位置しています）。 </li><li>顕微はさみを使用すると、房室レベルで両方の心房を分離心室から組織を接続切断して捨てます。任意の機械的な圧力を避ける心尖にAV-バルブレベルから心室壁を通してカットを実行します。 </li><li>心室を開き、鉗子で左側の自由壁を固定し、このように両方の左心室乳頭筋を見てみました。 </li><li>少し乳頭筋の準備の弁膜帆の一部を保存左前乳頭筋の両側の心室組織の横を離れてカットし、触れないように注意してくださいまたは、できるだけ多くの乳頭筋をストレッチ。乳頭筋からの残りの心室壁組織を解剖。 </li><li>乳頭筋の準備の両側に取り付け絹糸（7/0、メートル法0.5）aration、弁膜帆上の1つの筋肉の部分に1つ。温度32°Cが提案されているように、臓器浴溶液を充填し、カルボゲンでガスを供給した器官槽室で準備を修正。 </li></ol>乳頭筋の5平衡と刺激<ol><li>直ちに臓器浴中で固定した後、1ヘルツの刺激周波数の矩形パルス（2ミリ秒の持続時間および100 mAの電流）と乳頭筋調製物を刺激します。 </li><li>使用オーガンバスタイプの設定に応じて連続的に変化したり、頻繁に手動で変更（5分ごと）のいずれかによって、臓器浴溶液の頻繁な変更を確認してください。 </li><li>徐々に達しにおける最大単収縮力まで、プレテンションを上げます。プリテンションの増加は単収縮力のさらなる増強が続いていないときに最大単収縮力に達します。 </li><li>平衡の45〜60分後、実験プロトコルを開始します。 </li></ol>注：以下のとおり実験プロトコルは、生理学的および病態生理学的条件の下で心臓の収縮を特徴づけるために、標準的な操縦を含みます。代表的なセクションでは、詳細には、これらのプロトコルを記述し、また（表2参照）代表的な結果を示します。 <ol><li>実験プロトコルの記録と分析<ol><li>記録のために、十分な時間分解能（取得率≥1kHzの）で、適切なソフトウェアを使用しています。 </li><li>単収縮力の大きさ（高さ）、ソフトウェアプログラムで述べたようにテンション（TTP）と最大値の半分緩和時間（それぞれ、R 50 / TFallを）ピークまでの時間（ 例として図4を参照してください 、ADInstrumentsの5.5チャート）などのパラメータを分析します。 </li></ol></li></ol>

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著者は、彼らが競合する金融利害関係を有していないことを宣言します。

本稿では、我々は、マウスの心臓生理学と病理学に関連するいくつかの科学的な質問に答えるだけでなく、トランスジェニック系統の分析と新たな医薬品のアプローチの発見をサポートするために使用することができ、in vitroでマウス乳頭筋の収縮性を調査する方法を説明心臓の機能不全を治療することができます。我々は、心臓の筋肉の収縮の、生理的な病理学的および薬理学的特?...

心臓の収縮のために自分の役割を参照するイオンチャネルのようなタンパク質の調査は異なる発症機序を発見し、そのような虚血および心不全などの心臓疾患のための新しい治療戦略を確立することが不可欠です。 哺乳動物の心筋細胞の収縮機能は、種々のイオンチャネル、輸送体および他のタンパク質によって調節することが知られています。活動電位は、Ca 2+チャネルは、細胞外空間からのCa 2+流入につながる電圧依存筋細胞膜のL型の活性化を誘発し、その後のCa 2+の細胞収縮2をトリガのCa 2+放出（CICR）1を 、誘発しました。生理学的または病理学的ストレスに対する心臓の収縮と適応に中心的な役割を果たしている-signaling の Ca 2+。カテコールアミンは、このようにキャンプを合成するアデニル酸シクラーゼ（AC）を刺激する、心臓βアドレナリン受容体を活性化します。活性化され、protein個のCa 2+トランジェントと心収縮の1,3,4の変更の結果、L型Ca 2+チャネル 、ホスホランバンとリアノジン受容体のような異なる細胞内および細胞膜結合タンパク質をリン酸化する（PKA）のキナーゼ。 cAMPはホスホジエステラーゼ（PDE）によって分解されます。 βアドレナリン受容体以外のGs共役受容体の活性化はまた、cAMPの蓄積をもたらします。 孤立した心室筋ストリップで収縮測定の技術が十分に大きい哺乳動物種5-8のために確立されています。マウスにおいて、遺伝子ターゲティングの可能性に基づいて、マウス心臓の生理機能を分析するための方法を確立することが重要です。しかし、マウスでは孤立した筋肉製剤の生理学的特性に関する既存のデータは、実験条件9-12によって異なります。 記載された方法は、左心室の乳頭筋の事前の心収縮性を分析するために使用されin vitroで parations。心収縮の調査は、血圧、神経液刺激および物理的または代謝的ストレスのようなin vivoでの心臓収縮を、修正の影響の非存在下で行われます。収縮筋調製物の叩解速度が厳密に定義され、任意に変更することができます。単収縮力は周波数または温度を破って、そのようなカルシウム濃度のような特定の刺激との関連で分析することができます。また、この方法は、異なるシグナル伝達経路の成分を調査すると、上記の実験条件を制御することにより、遺伝的に改変されたマウスモデルの心臓の性能を比較するために使用することができます。

<table><tbody><tr><td>Sodium chloride</td><td>Sigma-Aldrich</td><td>S7653</td><td></td></tr><tr><td>Sodium bicarbonate</td><td>Sigma-Aldrich</td><td>S5761&amp;nbsp;</td><td></td></tr><tr><td>Potassium chloride</td><td>Sigma-Aldrich</td><td>P9333</td><td></td></tr><tr><td>Glucose</td><td>Sigma-Aldrich</td><td>D9434&amp;nbsp;</td><td></td></tr><tr><td>Sodium pyruvate</td><td>Sigma-Aldrich</td><td>P5280&amp;nbsp;</td><td></td></tr><tr><td>Calcium chloride dihydrate</td><td>Sigma-Aldrich</td><td>223506</td><td></td></tr><tr><td>Magnesium sulfate heptahydrate</td><td>Sigma-Aldrich</td><td>230391</td><td></td></tr><tr><td>Potassium phosphate monobasic</td><td>Sigma-Aldrich</td><td>P 5655</td><td></td></tr><tr><td>2,3-Butanedione monoxime</td><td>Sigma-Aldrich</td><td>B0753</td><td></td></tr><tr><td>3-Isobutyl-1-methylxanthine</td><td>Sigma-Aldrich</td><td>I5879</td><td>Hazard statement H 302, solve in DMSO</td></tr><tr><td>Dimethyl sulfoxide (DMSO)</td><td>Sigma-Aldrich</td><td>D2650</td><td></td></tr><tr><td>Isoprenaline hydrochloride</td><td>Sigma-Aldrich</td><td>I5627</td><td>Hazard statement H 315-H319-H335</td></tr><tr><td>Sodium Heparine 250.000 IE/10 ml</td><td>ratiopharm</td><td>PZN 3874685</td><td></td></tr><tr><td>Histamine dihydrochloride</td><td>Sigma-Aldrich</td><td>H7250</td><td>Hazard statement H 315-H 317-H319- H334-H335</td></tr></tbody></table>

contractility measurements on isolated papillary muscles for the investigation of cardiac inotropy in mice

成体マウスの心臓から単離された乳頭筋は異なる生理学的/病理学的状態の間の心収縮性を研究するために使用することができます。収縮特性は、独立して、血管の緊張または神経液性状態などの外部の影響を評価することができます。これは、単離された心筋細胞を持つ単一セル測定の間及び心エコー検査などのインビボ研究で科学的なアプローチを示しています。従って、乳頭筋調製物は、心臓の生理機能/病態生理学を研究するための優れたモデルとして機能し、薬剤による調節またはトランスジェニック動物モデルの探査などの調査のために使用することができます。ここでは、器官槽の設定における心収縮性を調査するために、マウスの左前方の乳頭筋を単離する方法について説明します。心室壁から単離された筋肉片の調製とは対照的に、乳頭筋は、筋TISSUに損傷を与えることなく、 全体として調製することができます。E深刻。器官槽の設定は、複数の温度制御され、毒ガスと電極を装備した器官槽室で構成されています。孤立した乳頭筋は、器官槽室に固定され、電気的に刺激されます。誘発単収縮力は、圧力変換器と、このような力の大きさをけいれんおよび動態を分析する単収縮のようなパラメータを使用して記録されています。異なる実験プロトコルは、カルシウムおよび周波数依存収縮ならびにカテコールアミンや他の医薬品などの収縮剤の用量反応曲線を調査するために行うことができます。さらに、急性虚血のような病理学的状態をシミュレートすることができます。

単離されたマウス乳頭筋調製物の収縮の測定のために、この原稿のプロトコルは、生理学的条件下で再現性のある実験の結果を達成するために最適な条件に調整されます。最適な実験条件を定義するために、我々は、器官浴温度および細胞外カルシウム濃度（12も参照）に変化するパイロット実験を行いました。ここで説明するプロトコルは、1.5mMの細胞外カルシウム濃度及?...

Watch this Scientific Journal Video about Contractility Measurements on Isolated Papillary Muscles for the Investigation of Cardiac Inotropy in Mice at JoVE.com

Contractility Measurements on Isolated Papillary Muscles for the Investigation of Cardiac Inotropy in Mice

マウスの左心室の乳頭筋は 、インビトロで心筋収縮性を調べるために使用することができます。この記事では詳細に心臓収縮特性を研究するためのアイソレーションと実験プロトコルを説明しています。

マウスの心臓変力作用の調​​査のために分離された乳頭筋の収縮の測定

Papillary muscle isolated from adult mouse hearts can be used to study cardiac contractility during different physiological/pathological conditions. The ...

contractility-measurements-on-isolated-papillary-muscles-for

Universidad de Cartagena UDEC

Research

JoVE Journal

Biology

14.9K ビュー.  Universität Heidelberg. マウスの左心室の乳頭筋は 、インビトロで心筋収縮性を調べるために使用することができます。この記事では詳細に心臓収縮特性を研究するためのアイソレーションと実験プロトコルを説明しています。 

ビデオ: Contractility Measurements on Isolated Papillary Muscles for the Investigation of Cardiac Inotropy in Mice

In vitro Measurements of Tracheal Constriction Using Mice

Transgenic and knockout mice have been powerful tools for the investigation of the physiology and pathophysiology of airways1,2. In vitro tensometry of isolated tracheal preparations has proven to be a useful assay of airway smooth muscle (ASM) contractile response in genetically modified mice. These in vitro tracheal preparations are relatively simple, provide a robust response, and retain both functional cholinergic nerve endings and muscle responses, even after long incubations.
Tracheal tensometry also provides a functional assay to study a variety of second messenger signaling pathways that affect contraction of smooth muscle. Contraction in trachea is primarily mediated by parasympathetic, cholinergic nerves that release acetylcholine onto ASM (Figure 1). The major ASM acetylcholine receptors are muscarinic M2 and M3 which are Gi/o and Gq coupled receptors, respectively3,4,5. M3 receptors evoke contraction by coupling to Gq to activate phospholipase C, increase IP3 production and IP3-mediated calcium release from the sarcoplasmic reticulum3,6,7. M2/Gi/o signaling is believed to enhance contractions by inhibition of adenylate cyclase leading to a decrease in cAMP levels5,8,9,10. These pathways constitute the so called "pharmaco-contraction coupling" of airway smooth muscle11. In addition, cholinergic signaling through M2 receptors (and modulated by M3 signaling) involves pathways that depolarize the ASM which in turn activate L-type, voltage-dependent calcium channels (Figure 1) and calcium influx (so called "excitation-contraction coupling")4,7. More detailed reviews on signaling pathways controlling airway constriction can be found4,12. The above pathways appear to be conserved between mice and other species. However, mouse tracheas differ from other species in some signaling pathways. Most prominent is their lack of contractile response to histamine and adenosine13,14, both well-known ASM modulators in humans and other species5,15.
Here we present protocols for the isolation of murine tracheal rings and the in vitro measurement of their contractile output. Included are descriptions of the equipment configuration, trachea ring isolation and contractile measurements. Examples are given for evoking contractions indirectly using high potassium stimulation of nerves and directly by depolarization of ASM muscle to activate voltage-dependent calcium influx (1. high K+, Figure 1). In addition, methods are presented for stimulations of nerves alone using electric field stimulation (2. EFS, Figure 1), or for direct stimulation of ASM muscle using exogenous neurotransmitter applied to the bath (3. exogenous ACH, Figure 1). This flexibility and ease of preparation renders the isolated trachea ring model a robust and functional assay for a number of signaling cascades involved in airway smooth muscle contraction.

In vitro Measurements of Tracheal Constriction Using Mice

Transgenic mice have been extremely useful in ascribing physiological function to genes. As such, research in general, and functional studies of airway, in particular, have undergone a remarkable shift toward murine models. Here we provide protocols for in vitro trachea constriction studies to evaluate smooth muscle function in murine airway.

マウスを用いた気管狭窄のin vitroでの測定で

Transgenic and knockout mice have been powerful tools for the investigation of the physiology and pathophysiology of airways1,2. In vitro tensometry of ...

医学

Cardiac Catheterization in Mice to Measure the Pressure Volume Relationship: Investigating the Bowditch Effect

Animal models that mimic human cardiac disorders have been created to test potential therapeutic strategies. A key component to evaluating these strategies is to examine their effects on heart function. There are several techniques to measure in vivo cardiac mechanics (e.g., echocardiography, pressure/volume relations, etc.). Compared to echocardiography, real-time left ventricular (LV) pressure/volume analysis via catheterization is more precise and insightful in assessing LV function. Additionally, LV pressure/volume analysis provides the ability to instantaneously record changes during manipulations of contractility (e.g., &#946;-adrenergic stimulation) and pathological insults (e.g., ischemia/reperfusion injury). In addition to the maximum (+dP/dt) and minimum (-dP/dt) rate of pressure change in the LV, an accurate assessment of LV function via several load-independent indexes (e.g., end systolic pressure volume relationship and preload recruitable stroke work) can be attained. Heart rate has a significant effect on LV contractility such that an increase in the heart rate is the primary mechanism to increase cardiac output (i.e., Bowditch effect). Thus, when comparing hemodynamics between experimental groups, it is necessary to have similar heart rates. Furthermore, a hallmark of many cardiomyopathy models is a decrease in contractile reserve (i.e., decreased Bowditch effect). Consequently, vital information can be obtained by determining the effects of increasing heart rate on contractility. Our and others data has demonstrated that the neuronal nitric oxide synthase (NOS1) knockout mouse has decreased contractility. Here we describe the procedure of measuring LV pressure/volume with increasing heart rates using the NOS1 knockout mouse model.

This article describes the measurement of murine left ventricular function via pressure/volume analysis at different heart rates.

ボーディッチ影響を調べる：圧力体積関係を測定するために、マウスにおける心臓カテーテル検査

Animal models that mimic human cardiac disorders have been created to test potential therapeutic strategies. A key component to evaluating these ...

Optical Imaging of Isolated Murine Ventricular Myocytes

The ability to isolate adult cardiac myocytes has permitted researchers to study a variety of cardiac pathologies at the single cell level. While advances in calcium sensitive dyes have permitted the robust optical recording of single cell calcium dynamics, recording of robust transmembrane optical voltage signals has remained difficult. Arguably, this is because of the low single to noise ratio, phototoxicity, and photobleaching of traditional potentiometric dyes. Therefore, single cell voltage measurements have long been confined to the patch clamp technique which while the gold standard, is technically demanding and low throughput. However, with the development of novel potentiometric dyes, large, fast optical responses to changes in voltage can be obtained with little to no phototoxicity and photobleaching. This protocol describes in detail how to isolate adult murine myocytes which can be used for cellular shortening, calcium, and optical voltage measurements. Specifically, the protocol describes how to use a ratiometric calcium dye, a single-excitation calcium dye, and a single excitation voltage dye. This approach can be used to assess the cardiotoxicity and arrhythmogenicity of various chemical agents. While phototoxicity is still an issue at the single cell level, methodology is discussed on how to reduce it.

We present the methodology for the isolation of murine myocytes and how to obtain voltage or calcium traces simultaneously with sarcomere shortening traces using fluorescence photometry with simultaneous digital cell geometry measurements.

単離マウス心室筋細胞の光学イメージング

The ability to isolate adult cardiac myocytes has permitted researchers to study a variety of cardiac pathologies at the single cell level. While advances ...

生物工学

Isolation, Culture, and Functional Characterization of Adult Mouse Cardiomyoctyes

The use of primary cardiomyocytes (CMs) in culture has provided a powerful complement to murine models of heart disease in advancing our understanding of heart disease. In particular, the ability to study ion homeostasis, ion channel function, cellular excitability and excitation-contraction coupling and their alterations in diseased conditions and by disease-causing mutations have led to significant insights into cardiac diseases. Furthermore, the lack of an adequate immortalized cell line to mimic adult CMs, and the limitations of neonatal CMs (which lack many of the structural and functional biomechanics characteristic of adult CMs) in culture have hampered our understanding of the complex interplay between signaling pathways, ion channels and contractile properties in the adult heart strengthening the importance of studying adult isolated cardiomyocytes. Here, we present methods for the isolation, culture, manipulation of gene expression by adenoviral-expressed proteins, and subsequent functional analysis of cardiomyocytes from the adult mouse. The use of these techniques will help to develop mechanistic insight into signaling pathways that regulate cellular excitability, Ca2+ dynamics and contractility and provide a much more physiologically relevant characterization of cardiovascular disease.

Here we describe the isolation of adult mouse cardiomyoctyes using a Langendorff perfusion system. The resulting cells are Ca2+-tolerant, electrically quiescent and can be cultured and transfected with adeno- or lentiviruses to manipulate gene expression. Their functionality can also be analyzed using the MMSYS system and patch clamp techniques.

アイソレーション、文化、および成体マウスCardiomyoctyesの機能解析

The use of primary cardiomyocytes (CMs) in culture has provided a powerful complement to murine models of heart disease in advancing our understanding of ...

生物学

Isolation and Physiological Analysis of Mouse Cardiomyocytes

Cardiomyocytes, the workhorse cell of the heart, contain exquisitely organized cytoskeletal and contractile elements that generate the contractile force used to pump blood. Individual cardiomyocytes were first isolated over 40 years ago in order to better study the physiology and structure of heart muscle. Techniques have rapidly improved to include enzymatic digestion via coronary perfusion. More recently, analyzing the contractility and calcium flux of isolated myocytes has provided a vital tool in the cellular and sub-cellular analysis of heart failure. Echocardiography and EKGs provide information about the heart at an organ level only. Cardiomyocyte cell culture systems exist, but cells lack physiologically essential structures such as organized sarcomeres and t-tubules required for myocyte function within the heart. In the protocol presented here, cardiomyocytes are isolated via Langendorff perfusion. The heart is removed from the mouse, mounted via the aorta to a cannula, perfused with digestion enzymes, and cells are introduced to increasing calcium concentrations. Edge and sarcomere detection software is used to analyze contractility, and a calcium binding fluorescent dye is used to visualize calcium transients of electrically paced cardiomyocytes; increasing understanding of the role cellular changes play in heart dysfunction. Traditionally used to test drug effects on cardiomyocytes, we employ this system to compare myocytes from WT mice and mice with a mutation that causes dilated cardiomyopathy. This protocol is unique in its comparison of live cells from mice with known heart function and known genetics. Many experimental conditions are reliably compared, including genetic or environmental manipulation, infection, drug treatment, and more. Beyond physiologic data, isolated cardiomyocytes are easily fixed and stained for cytoskeletal elements. Isolating cardiomyocytes via perfusion is an extremely versatile method, useful in studying cellular changes that accompany or lead to heart failure in a variety of experimental conditions.

Individual cardiomyocytes from wild type and mutant mice can be isolated from the heart in order to study their contractility and calcium transients. This allows characterization of the contribution of cellular dysfunction to heart dysfunction from any cause.

マウス心筋細胞の単離と生理解析

Cardiomyocytes, the workhorse cell of the heart, contain exquisitely organized cytoskeletal and contractile elements that generate the contractile force ...

Dynamic Measurement and Imaging of Capillaries, Arterioles, and Pericytes in Mouse Heart

Coronary arterial tone along with the opening or closing of the capillaries largely determine the blood flow to cardiomyocytes at constant perfusion pressure. However, it is difficult to monitor the dynamic changes of the coronary arterioles and the capillaries in the whole heart, primarily due to its motion and non-stop beating. Here we describe a method that enables monitoring of arterial perfusion rate, pressure and the diameter changes of the arterioles and capillaries in mouse right ventricular papillary muscles. The mouse septal artery is cannulated and perfused at a constant flow or pressure with the other dynamically measured. After perfusion with a fluorescently labeled lectin (e.g., Alexa Fluor-488 or -633 labeled Wheat-Germ Agglutinin, WGA), the arterioles and capillaries (and other vessels) in right ventricle papillary muscle and septum could be readily imaged. The vessel-diameter changes could then be measured in the presence or absence of heart contractions. When genetically encoded fluorescent proteins were expressed, specific features could be monitored. For examples, pericytes were visualized in mouse hearts that expressed NG2-DsRed. This method has provided a useful platform to study the physiological functions of capillary pericytes in heart. It is also suitable for studying the effect of reagents on the blood flow in heart by measuring the vascular/capillary diameter and the arterial luminal pressure simultaneously. This preparation, combined with a state-of-the-art optic imaging system, allows one to study the blood flow and its control at cellular and molecular level in the heart under near-physiological conditions.

Presented here is a protocol to study the coronary microcirculation in living murine heart tissue by ex vivo monitoring of the arterial perfusion pressure and flow that maintains the pressure, as well as vascular tree components including the capillary beds and pericytes, as the septal artery is cannulated and pressurized.

マウス心臓における毛細血管、細動脈、および周囲細胞の動的測定とイメージング

Coronary arterial tone along with the opening or closing of the capillaries largely determine the blood flow to cardiomyocytes at constant perfusion ...

Revealing Subtle Changes in Cardiac Function using Transthoracic Dobutamine Stress Echocardiography in Mice

Left ventricular (LV) dysfunction paves the final pathway for a multitude of cardiac disorders. With the non-invasive high-frequency transthoracic dobutamine stress echocardiography in humans, a reductionist investigation approach to unmask subtle changes in cardiac function has become possible. Here, we provide a protocol for using this technique in mice to facilitate expanded analysis of LV architecture and function in physiology and pathology enabling the observation of alterations in models of cardiac disease hidden in unstressed hearts. This investigation can be performed in one and the same animal and allows both, basal and pharmacologically stress-induced measurements. We outline detailed criteria for appropriate anesthesia, imaging-based LV analysis, consideration of intra- and interobserver variability, and obtaining positive inotrope response that can be attained in mice after intraperitoneal injection of dobutamine under near physiological conditions. To recapitulate the characteristics of human physiology and disease in small animal models, we highlight critical pitfalls in evaluation, e.g., a pronounced Bowditch effect in mice. To further meet translational objectives, we compare stress-induced effects in humans and mice. When used in translational studies, attention must be paid to physiological differences between mice and human. Experimental rigor dictates that some parameters assessed in patients can only be used with caution due to restrictions in spatial and temporal resolution in mouse models.

Left ventricular dysfunction constitutes the final common pathway for a host of cardiac disorders. We here provide a detailed protocol of transthoracic dobutamine stress echocardiography approach for comprehensive evaluation of the left ventricular function of mouse models of cardiac disease as well as cardiac phenotyping.

Left ventricular (LV) dysfunction paves the final pathway for a multitude of cardiac disorders. With the non-invasive high-frequency transthoracic ...

Analysis of Cardiac Contractile Dysfunction and Ca2+ Transients in Rodent Myocytes

Contractile dysfunction and Ca2+ transients are often analyzed at the cellular level as part of a comprehensive assessment of cardiac-induced injury and/or remodeling. One approach for assessing these functional alterations utilizes unloaded shortening and Ca2+ transient analyses in primary adult cardiac myocytes. For this approach, adult myocytes are isolated by collagenase digestion, made Ca2+ tolerant, and then adhered to laminin-coated coverslips, followed by electrical pacing in serum-free media. The general protocol utilizes adult rat cardiac myocytes but can be readily adjusted for primary myocytes from other species. Functional alterations in myocytes from injured hearts can be compared to sham myocytes and/or to in vitro therapeutic treatments. The methodology includes the essential elements needed for myocyte pacing, along with the cell chamber and platform components. The detailed protocol for this approach incorporates the steps for measuring unloaded shortening by sarcomere length detection and cellular Ca2+ transients measured with the ratiometric indicator Fura-2 AM, as well as for raw data analysis.

Analysis of Cardiac Contractile Dysfunction and Ca2+ Transients in Rodent Myocytes

A set of protocols are presented that describe the measurement of contractile function via sarcomere length detection along with calcium (Ca2+) transient measurement in isolated rat myocytes. The application of this approach for studies in animal models of heart failure is also included.

げっ歯類筋細胞における心収縮機能障害とCa2+ 一過性の解析

Contractile dysfunction and Ca2+ transients are often analyzed at the cellular level as part of a comprehensive assessment of cardiac-induced injury ...

Measurement of Heart Contractility in Isolated Adult Human Primary Cardiomyocytes

The evaluation of changes in heart contractility is essential during preclinical development for new cardiac- and non-cardiac-targeted compounds. This paper describes a protocol for assessing changes in contractility in adult human primary ventricular cardiomyocytes utilizing the MyoBLAZER, a non-invasive optical method that preserves the normal physiology and pharmacology of the cells. This optical recording method continuously measures contractility transients from multiple cells in parallel, providing both medium-throughput and valuable information for each individual cell in the field of view, enabling the real-time tracking of drug effects. The cardiomyocyte contractions are induced by paced electrical field stimulation, and the acquired bright field images are fed to an image-processing software that measures the sarcomere shortening across multiple cardiomyocytes. This method rapidly generates different endpoints related to the kinetics of contraction and relaxation phases, and the resulting data can then be interpreted in relation to different concentrations of a test article. This method is also employed in the late stages of preclinical development to perform follow-up mechanistic studies to support ongoing clinical studies. Thus, the adult human primary cardiomyocyte-based model combined with the optical system for continuous contractility monitoring has the potential to contribute to a new era of in vitro cardiac data translatability in preclinical medical therapy development.

This protocol describes how to measure contractility in adult human primary cardiomyocytes from donor hearts with the MyoBLAZER system, a reliable platform for assessing drug-induced changes in contractility during preclinical development.

単離された成人ヒト一次心筋細胞における心臓収縮性の測定

The evaluation of changes in heart contractility is essential during preclinical development for new cardiac- and non-cardiac-targeted compounds. This ...

Mechanical Control of Relaxation Using Intact Cardiac Trabeculae

Diastolic dysfunction is a common phenotype across cardiovascular disease presentations. In addition to elevated cardiac stiffness (elevated left ventricular end-diastolic pressure), impaired cardiac relaxation is a key diagnostic indicator of diastolic dysfunction. While relaxation requires the removal of cytosolic calcium and deactivation of sarcomeric thin filaments, targeting such mechanisms has yet to provide effective treatments. Mechanical mechanisms, such as blood pressure (i.e., afterload), have been theorized to modify relaxation. Recently, we showed that modifying the strain rate of a stretch, not afterload, was both necessary and sufficient to modify the subsequent relaxation rate of myocardial tissue. The strain rate dependence of relaxation, called the mechanical control of relaxation (MCR), can be assessed using intact cardiac trabeculae. This protocol describes the preparation of a small animal model, experimental system and chamber, isolation of the heart and subsequent isolation of a trabecula, preparation of the experimental chamber, and experimental and analysis protocols. Evidence for lengthening strains in the intact heart suggests that MCR might provide new arenas for better characterization of pharmacological treatments, along with a method to assess myofilament kinetics in intact muscles. Therefore, studying the MCR may elucidate a path to novel approaches and new frontiers in the treatment of heart failure.

Rapid myocardial and cardiac relaxation is essential for normal physiology. Mechanical relaxation mechanisms are now known to be dependent on strain rate. This protocol provides an overview of the acquisition and analysis of experiments to further study the mechanical control of relaxation.

マウスの心臓変力作用の調査のために分離された乳頭筋の収縮の測定

要約

さらに動画を探す

この動画の章

マウスを用いた気管狭窄のin vitroでの測定で

ボーディッチ影響を調べる：圧力体積関係を測定するために、マウスにおける心臓カテーテル検査

単離マウス心室筋細胞の光学イメージング

アイソレーション、文化、および成体マウスCardiomyoctyesの機能解析

マウス心筋細胞の単離と生理解析

マウス心臓における毛細血管、細動脈、および周囲細胞の動的測定とイメージング

Revealing Subtle Changes in Cardiac Function using Transthoracic Dobutamine Stress Echocardiography in Mice

げっ歯類筋細胞における心収縮機能障害と^Ca2+ 一過性の解析

単離された成人ヒト一次心筋細胞における心臓収縮性の測定

無傷の心臓小柱を用いたリラクゼーションの機械的制御

マウスの心臓変力作用の調​​査のために分離された乳頭筋の収縮の測定

要約

さらに動画を探す

この動画の章

マウスを用いた気管狭窄のin vitroでの測定で

ボーディッチ影響を調べる：圧力体積関係を測定するために、マウスにおける心臓カテーテル検査

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Revealing Subtle Changes in Cardiac Function using Transthoracic Dobutamine Stress Echocardiography in Mice

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無傷の心臓小柱を用いたリラクゼーションの機械的制御

マウスの心臓変力作用の調査のために分離された乳頭筋の収縮の測定

げっ歯類筋細胞における心収縮機能障害と^Ca2+ 一過性の解析