Name: contractility measurements on isolated papillary muscles for the investigation of cardiac inotropy in mice
Uploaded: 2015-09-17T15:00:00.000+00:00
Duration: 6 min 22 s
Description: Watch this Scientific Journal Video about Contractility Measurements on Isolated Papillary Muscles for the Investigation of Cardiac Inotropy in Mice at JoVE.com

이 작품은 독일 연구 협회 (KFO 196 &quot;Signaltransduktion BEI adaptativen 싶게 maladaptiven kardialen 리모델링-Prozessen&quot;, 1638 / 1-2 FR)에 의해 심장 혈관 연구, 건강 연구의 독일 센터의 일부에 대한 DZHK (독일 센터에 의해 지원되었다 , BMBF (교육 및 연구 독일 정부) 이니셔티브)이다.

주 : 분리 과정의 기본 단계는도 1에 도시 된 모든 단계가 다음 프로토콜에서 상세히 설명된다.. 유두근 분리, 기관 목욕 챔버에 장착, 수집 및 분석은 연속적인 의무 시간 척도에서 수행된다. 모든 동물 실험은 동물의 보호에 관한 독일 법률에 따라 수행하고, 하이델베르크 대학의 윤리 심사위원회에 의해 승인되었다. 계측 1. 준비 <ol><li> 수축력을 위해 측정은 다중 챔버 기관 목욕 설정을 사용합니다. 생체 수축력 기관 목욕 설정의 구성 요소는 그림 2에 표시됩니다. 참고 : 유두근의 준비 및 실험 프로토콜의 시작 사이의 시간 설정, 장비를 최소화하고 실험 tissue.This를 수집 제공하기로 버퍼를 사전 준비하려면조직 실험을 실시 가능한 남아있는 시간의 양을 최대 ES. </li><li> 컴퓨터와 데이터 수집 장비를 시작합니다. 장기 목욕 열 (사전에 32 ° C)의 전원을 켜고 설정 온도에 단위를 할 수 있습니다. </li><li> 수집 장비를 준비합니다. 소프트웨어 설명서에 언급 된 데이터를 기록 시작합니다. </li><li> 확인하고 각 채널 (필요한 경우) 캘리브레이션을 수행하고 인증 된 중량에 의해 공급 -2- g 력 (즉, 채널과 관련된) 각각의 힘 센서로부터 공급 된 전기 신호를 표준화하는 모든 채널을 제로. </li><li> 장기 목욕 챔버에 가스 공급 (95 %, O2 / 5 % CO 2)를 켭니다. 지속적으로 전체 프로토콜 측정하는 동안 모든 실 가스. </li></ol> 버퍼 및 생리 솔루션 2. 준비 <ol><li> 119 mM의 NaCl을 최종 농도를 달성하기-Henseleit 크렙스 완충액을 제조; 25 밀리미터의 NaHCO3; 4.6 밀리미터의 KCl; 11MM 혈당; 1 mM의 나-Pyruvate; 1.5 mM의 염화칼슘 (2); 1.64 mm의 4 황산; 1.18 mM의 KH 2 PO 4 (표 1 생리 솔루션을 참조) 7.4으로 산도를 조정합니다. </li><li> 추가 30MM 2,3- 부탄 monoxime (BDM) 50 IE 헤파린 / ml의 단계 2.1에 설명 된대로 분리시 사용하는 별도의 크렙스 - Henseleit 버퍼 ​​솔루션을 준비합니다. 4 ° C를 (표 1 제조 솔루션을 참조) 쿨 솔루션입니다. 표 1에 기재된 시뮬레이션 허혈, 허혈 용액을 제조 하였다. </li><li> 칼슘 +의 프로토콜 용 - 의존 수축력 요청 최종 농도 크렙스 - Henseleit 완충 용액에 칼슘을 추가합니다. 참고 : 직접 사용하기 전에이 솔루션을 준비하고 Calciumcarbonate의 침전을 방지하기 위해 carbogen와 GASS. 사용하기 전에 32 ° C에 Prewarm 솔루션입니다. </li></ol> 유두 절제술 절차를 수행하는 동안 사용되는 가스 처리 튜브 및 해부 접시 3. 준비 <ol><li> 부드러운 가스 연결전문가가 작동 가스와 연결 (산소 100 %, 또는 carbogen)에 튜브 (외부 직경 2-4mm)를 노래. </li><li> 해부 접시 내부 피팅 가스 처리 관의 닫힌 고리를 만듭니다. 가스 처리 튜브를 연속 기포가 보장 수회 천공. 이 관은 가스 배출은 여러 번 사용될 수있다. </li><li> 핀 그것에 결합 될 수 있도록 저부 (0.5 cm 두께)에 실리콘 엘라스토머와 해부 접시를 준비한다. 이 접시를 여러 번 사용될 수있다. </li></ol> 마우스의 왼쪽 전방 유두 근육 4. 분리 참고 : 유두근의 분리를 시작하기 전에, 가스 라인이 막힘의 명확 있는지 확인합니다. <ol><li> 유두근의 제조를 시작하기 전에 상기 프로토콜 1-3 절에서 설명한 바와 같이 기관 욕 설정을 준비한다. 실험의 날에 모든 솔루션을 준비합니다. </li><li> 자궁 경부 전위 accordi로 (약 8~12주 이전) 마우스를 희생전문적인 작업과 제도적 지침에 NG. </li><li> 앞발을 고정하여 지느러미의 위치에있는 동물을 수정하고 해부 보드에 발을 뒷다​​리, 날카로운 뼈 가위로 갈비뼈를 절단하여 양측의 흉부 측면을 연 다음 횡단 잘라 다이어프램을 잘라. 심낭을 제거합니다. 지금 심장과 대동맥 액세스 할 수 있습니다. </li><li> 심장에 가까운 혈관 truncus에 무딘 집게로 마음을 수정하고 폐에서 가위와 주변 조직에 신속하게 마음을 분리합니다. </li><li> 산소 (단계 2.2)과 가스실 냉각 준비 솔루션 가득 페트리 접시에 뛰는 심장을 전송합니다. 심장이 이길 집게로 심장 정점을 터치를 통해 부드럽게 심장의 수축을 자극 할 수 있습니다. </li><li> 즉시 마음이 완전히 exsanguinous이다, O 2로 냉각 준비 솔루션 (단계 2.2)로 가득하고 가스실 해부 접시에 전송할 수 있습니다. 사용이 단계 실체 현미경에서. </li><li> 난방 수정마음 (우심실이 운영자의보기에서 오른쪽에 위치) 지느러미에서 볼 수 있도록 우심실을 통해 작은 핀을 실온. </li><li> 사용하여 미세 수술 가위 심실에서 조직을 연결, 방실 수준 모두에서 심방을 잘라 분리하고 버린다. 기계적 압력을 피 마음의 정점에 AV-밸브 수준에서 심실 벽을 통해 상처를 수행합니다. </li><li> 뇌실을 열고, 따라서 좌심실 유두 근육 모두를 살펴 가진, 집게와 왼쪽면 무료 벽을 고정한다. </li><li> 약간 유두근 준비에 판막 항해의 일부를 보존 왼쪽 전방 유두근의 양쪽에있는 심실 조직 측면을 절단과 접촉을 피하거나 최대한 유두 근육을 스트레칭. 유두 근육에 남아있는 심실 벽의 조직을 해부하다. </li><li> 유두근 준비의 양쪽에 부착 실크 쓰레드 (7/0, 0.5 미터)aration, 판막 항해에 하나는 근육 부분에 하나. 온도 32 ° C가 제안으로, 장기 목욕 솔루션으로 가득 carbogen와 가스실 기관 목욕 실에서 준비를 수정합니다. </li></ol> 유두근 5. 평형과 자극 <ol><li> 즉시 기관 욕에 정착 후 1 Hz에서 자극의 주파수에서 직사각형 펄스 (2 MS의 기간 및 100mA의 전류) 유두근 제제를 자극한다. </li><li> 지속적인 변화 또는 사용 기관 목욕 유형의 설정에 따라 자주 사용 설명서 변경 (매 5 분)에 의해 중, 장기 목욕 솔루션의 빈번한 변화를 확인합니다. </li><li> 도달에 점차적으로 최대 트 힘까지 텐션을 증가시킨다. 겉치레의 증가가 트의 힘에 더 보강으로 따르지 않을 경우 최대 트 힘에 도달. </li><li> 평형의 45 ~ 60 분 후, 실험 프로토콜을 시작합니다. </li></ol> 참고 : 아래에 설명 된 실험 프로토콜은 생리와 병리 생리 학적 조건에서 심장 수축력의 특성을 표준 연습을 포함한다. 대표 섹션에서 우리는 또한 대표적인 결과를 보여주는 구체적으로 이러한 프로토콜을 설명 (또한 표 2 참조). <ol><li> 녹화 및 실험 프로토콜 분석 <ol><li> 기록을 위해, 적절한 시간 해상도 (취득 비율 ≥의 1kHz에서)에 적합한 소프트웨어를 사용합니다. </li><li> 트 힘의 크기 (높이), 긴장 (TTP)와 (예를 들어 그림 4 참조, ADInstruments의 5.5 도표를 포함합니다) 소프트웨어 프로그램에서 언급 한 바와 같이 반 최대한의 휴식 시간 (R 50는 각각 / TFall를) 피크 시간을 포함하여 매개 변수를 분석 할 수 있습니다. </li></ol></li></ol>

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G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Changes+in+intracellular+free+calcium+concentration+during+long+exposures+to+simulated+ischemia+in+isolated+mammalian+ventricular+muscle.">Changes in intracellular free calcium concentration during long exposures to simulated ischemia in isolated mammalian ventricular muscle.</a> Circ Res. 71 (1), 58-69 (1992).</li></ol>

저자는 그들이 더 경쟁 재정적 이익이 없다는 것을 선언합니다.

이 논문에서는 마우스에서 심장 생리학 및 병리학 관련된 여러 과학 질문에 응답뿐만 아니라 형질 전환 라인 분석 및 새로운 약학 적 접근법의 검색을 지원하는 데 사용할 수있는 시험 관내 뮤린 유두근 수축력을 조사하는 방법을 서술 심장 기능 장애를 치료한다. 우리는 심근 수축력의 생리 병리학 적 및 약리학 적 특성을 평가하기 위해,이 방법의 사용을 예시한다 (도 3 참조)...

심장 수축성 그들의 역할을 참조 이온 채널 단백질 등의 조사는 다른 pathomechanisms를 발견하고 그러한 허혈 및 심장 마비와 같은 심장 질환에 대한 새로운 치료 전략을 구축하는 것이 필수적이다. 포유류 심근 수축 기능은 다양한 이온 채널, 전송기 및 다른 단백질에 의해 조절되는 것으로 알려져있다. 활동 전위는 2 + 채널이 세포 외 공간에서 칼슘 유입에 이르게이어서 칼슘 2 +에 휴대 수축 2 트리거 칼슘 2 + 릴리스 (CICR 1), 유도 된 칼슘 전압 의존 sarcolemmal의 L 형의 활성화를 불러 일으켰다. 생리 학적 또는 병리학 적 스트레스에 심장 수축력과 적응에 중심적인 역할을 -signaling 칼슘. 카테콜아민 따라서 캠프를 합성 아데 닐 레이트 사이 클라 (AC)을 자극, 심장 β 아드레날린 수용체를 활성화합니다. 활성화되는, PROTEIN 칼슘 2 + 과도 심장 수축력의 1,3,4의 수정의 결과로 L 형 칼슘 채널, phospholamban 및 ryanodine 수용체와 같은 다른 세포와 막 관련 단백질을 인산화 (PKA)을 키나제. 캠프 포스 (PDE)에 의해 분해된다. β - 아드레날린 수용체 이외의 GS-결합 수용체의 활성화는 또한 캠프의 축적으로 이어집니다. 절연 심실 근육 스트립 수축력 측정 기술은 물론 더 큰 포유류 5-8 확립된다. 유전자의 가능성이 생쥐 대상에 기초하여, 쥐 심장 생리학을 분석하는 방법을 확립하는 것이 중요하다. 그러나 생쥐에서 고립 근육 준비의 생리적 특성에 대한 기존의 데이터는 실험 조건 9-12에 따라 다릅니다. 한 방법은 좌심실 유두근 사전의 심장 수축력을 분석하는 데 사용됩니다체외에서 parations. 심장 수축력의 조사는 혈압, neurohumoral 자극과 신체 대사 스트레스 등의 생체 내 심장 수축력을 수정 영향의 부재에서 수행된다. 계약 근육 준비의 박동 속도는 엄격하게 정의 임의로 변경 될 수 있습니다. 트 위치 력 특정 칼슘 농도로서 자극, 주파수 또는 온도를 상회의 맥락에서 분석 될 수있다. 또한,이 방법은 상이한 신호 경로 구성 요소를 조사하고, 상기 언급 된 실험 조건을 제어함으로써, 유전자 변형 마우스 모델의 심장 성능을 비교하기 위해 사용될 수있다.

<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

성인 마우스 마음에서 격리 유두근는 다른 생리 / 병리 적 조건에서 심장 수축력을 연구하는 데 사용할 수 있습니다. 수축 특성은 독립적으로 혈관 TONUS neurohumoral 또는 상태와 같은 외부의 영향을 평가할 수있다. 그것은 고립 된 심장 근육 세포와 단일 세포 측정 사이와 심 초음파 등의 생체 내 연구의 과학적인 접근 방식을 보여줍니다. 우수한 모델이 심장 생리학 / 병태를 연구하고되는 약물에 의해 변조 또는 트랜스 제닉 동물 모델의 탐색과 같은 조사를 위해 사용될 수있다, 따라서, 유두근 제제는 역할을한다. 여기, 우리는 장기 목욕 설정에서 심장 수축력을 조사하기 위해 쥐의 좌전 유두근을 분리하는 방법을 설명합니다. 심실 벽으로부터 격리 근육 스트립 제제와 대조적으로, 유두근은 근육 tissu TOTO을 손상시키지 않고 제조 할 수있다심각 전자. 장기 화장실 설치는 여러 온도 조절, 기체를 첨가 전극 장착 된 장기 목욕 챔버로 구성되어 있습니다. 격리 된 유두 근육 기관 목욕 실에서 해결 전기적 자극한다. 경련 유발 력은 그러한 힘 진폭 트 및 동력학 분석되는 트 같이 압력 변환기 및 파라미터를 이용하여 기록된다. 다른 실험 프로토콜 같은 카테콜아민 또는 다른 약제로서 수축 화제의 칼슘 및 주파수 별 수축뿐만 아니라, 용량 - 반응 곡선을 조사하기 위하여 수행 될 수있다. 또한 허혈과 같은 병리학 적 급성 조건을 시뮬레이션 할 수있다.

절연 뮤린 유두근 제제의 수축력 측정이 원고의 프로토콜은 생리 학적 조건 하에서 실험 재현성있는 결과를 달성하기 위해 최적의 상태로 조정된다. 최적의 실험 조건을 정의하기 위해 우리는 기관 욕 온도 및 세포 외 칼슘 농도 (도 12 참조) 가변 파일럿 실험을 수행 하였다. 여기에 설명 된 프로토콜은 1.5 mm의 세포 외 칼슘 농도 및 32 ° C의 온도로 수행 하였다. 기저 ...

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

뮤린 좌심실 유두근는 체외에서 심근 수축력을 조사하는데 사용될 수있다. 이 문서 자세히 분리 실험 프로토콜 심장 수축 특성을 연구에 대해 설명합니다.

마우스의 심장 수축력의 조사에 대 한 격리 유두 근육의 수축력 측정

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

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Research

JoVE Journal

Biology

14.9K 조회수.  Universität Heidelberg.  뮤린 좌심실 유두근는 체외에서 심근 수축력을 조사하는데 사용될 수있다. 이 문서 자세히 분리 실험 프로토콜 심장 수축 특성을 연구에 대해 설명합니다. 

비디오: 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.

마우스를 사용 Tracheal 수축의 체외 측정에서

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

연구

의학

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.

Bowditch 효과 조사 : 압력 볼륨 관계를 측정하기 위해 마우스의 심장 도관

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

Echocardiographic Approaches and Protocols for Comprehensive Phenotypic Characterization of Valvular Heart Disease in Mice

The aim of this manuscript and accompanying video is to provide an overview of the methods and approaches used for imaging heart valve function in rodents, with detailed descriptions of the appropriate methods for anesthesia, the echocardiographic windows used, the imaging planes and probe orientations for image acquisition, the methods for data analysis, and the limitations of emerging technologies for the evaluation of cardiac and valvular function. Importantly, we also highlight several future areas of research in cardiac and heart valve imaging that may be leveraged to gain insights into the pathogenesis of valve disease in preclinical animal models. We propose that using a systematic approach to evaluating cardiac and heart valve function in mice can result in more robust and reproducible data, as well as facilitate the discovery of previously underappreciated phenotypes in genetically-altered and/or physiologically-stressed mice.

This protocol provides a detailed description of the echocardiographic approach for comprehensive phenotyping of heart and heart valve function in mice.

마우스의 심장 판막 질환의 종합 표현형 특성에 대한 심 초음파 접근 및 프로토콜

The aim of this manuscript and accompanying video is to provide an overview of the methods and approaches used for imaging heart valve function in ...

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.

절연, 문화, 그리고 성인 마우스 된 심근의 기능적 특성

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

생물학

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.

마우스 심근의 분리 및 생리 학적 분석

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.

마우스 심장의 모세혈관, 동맥 및 페리사이클의 동적 측정 및 이미징

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 ...

Assessment of Myofilament Ca2+ Sensitivity Underlying Cardiac Excitation-contraction Coupling

Heart failure and cardiac arrhythmias are the leading causes of mortality and morbidity worldwide. However, the mechanism of pathogenesis and myocardial malfunction in the diseased heart remains to be fully clarified. Recent compelling evidence demonstrates that changes in the myofilament Ca2+ sensitivity affect intracellular Ca2+ homeostasis and ion channel activities in cardiac myocytes, the essential mechanisms responsible for the cardiac action potential and contraction in healthy and diseased hearts. Indeed, activities of ion channels and transporters underlying cardiac action potentials (e.g., Na+, Ca2+ and K+ channels and the Na+-Ca2+ exchanger) and intracellular Ca2+ handling proteins (e.g., ryanodine receptors and Ca2+-ATPase in sarcoplasmic reticulum (SERCA2a) or phospholamban and its phosphorylation) are conventionally measured to evaluate the fundamental mechanisms of cardiac excitation-contraction (E-C) coupling. Both electrical activities in the membrane and intracellular Ca2+ changes are the trigger signals of E-C coupling, whereas myofilament is the functional unit of contraction and relaxation, and myofilament Ca2+ sensitivity is imperative in the implementation of myofibril performance. Nevertheless, few studies incorporate myofilament Ca2+ sensitivity into the functional analysis of the myocardium unless it is the focus of the study. Here, we describe a protocol that measures sarcomere shortening/re-lengthening and the intracellular Ca2+ level using Fura-2 AM (ratiometric detection) and evaluate the changes of myofilament Ca2+ sensitivity in cardiac myocytes from rat hearts. The main aim is to emphasize that myofilament Ca2+ sensitivity should be taken into consideration in E-C coupling for mechanistic analysis. Comprehensive investigation of ion channels, ion transporters, intracellular Ca2+ handling, and myofilament Ca2+ sensitivity that underlie myocyte contractility in healthy and diseased hearts will provide valuable information for designing more effective strategies of translational and therapeutic value.

Assessment of Myofilament Ca2+ Sensitivity Underlying Cardiac Excitation-contraction Coupling

This paper describes a protocol that assesses the changes of myofilament Ca2+ sensitivity during contraction in isolated cardiac myocytes from rat heart. Together with cardiac electrophysiology, systolic/diastolic cytosol Ca2+ levels and contraction/relaxation, this measurement is imperative in underpinning the mechanisms mediating cardiac excitation-contraction coupling in healthy and diseased hearts.

Myofilament 칼슘의 평가<sup&gt; 2 +</sup&gt; 감도 근본적인 심장 여진 수축 커플 링

Heart failure and cardiac arrhythmias are the leading causes of mortality and morbidity worldwide. However, the mechanism of pathogenesis and myocardial ...

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.

설치류 근육 세포에서 심장 수축 기능 장애 및Ca 2+ 과도 현상 분석

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.

고립된 성인 인간 원발성 심근세포의 심장 수축성 측정

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

마우스의 심장 수축력의 조사에 대 한 격리 유두 근육의 수축력 측정

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