Name: a model of long-term ventricular fibrillation in isolated rat hearts
Uploaded: 2023-02-17T14:15:00
Description: Watch this Scientific Journal Video about A Model of Long-Term Ventricular Fibrillation in Isolated Rat Hearts at JoVE.com

이 작업은 심혈관 외과, First Medical Center, Chinese PLA General Hospital 및 Laboratory Animal Center, Chinese PLA General Hospital의 지원으로 수행되었습니다.

이 조사에 사용된 모든 실험 절차와 프로토콜은 PLA 종합병원의 동물 관리 및 사용 위원회에서 검토하고 승인했습니다.
1. Langendorff 장치 준비
<ol><li>Krebs-Henseleit(K-H) 완충액을 준비합니다. K-H 완충액을 제조하기 위해, 다음을 증류수에 첨가한다: 118.0 mM NaCl, 4.7 mM KCl, 1.2 mM MgSO4, 1.2 mM NaH2PO4, 1.8 mM CaCl2, 25.0 mM NaHCO3, 11.1 mM 글루코스</...

<ol>
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(174), e62335 (2021).</li><li>Jungen, C., 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=Impact+of+intracardiac+neurons+on+cardiac+electrophysiology+and+arrhythmogenesis+in+an+ex+vivo+Langendorff+system.">Impact of intracardiac neurons on cardiac electrophysiology and arrhythmogenesis in an ex vivo Langendorff system.</a> Journal of Visualized Experiments. 135, e57617 (2018).</li><li>Koretsune, Y., Marban, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+calcium+in+the+pathophysiology+of+ventricular+fibrillation+and+in+the+pathogenesis+of+postarrhythmic+contractile+dysfunction.">Cell calcium in the pathophysiology of ventricular fibrillation and in the pathogenesis of postarrhythmic contractile dysfunction.</a> Circulation. 80 (2), 369-379 (1989).</li><li>Brazier, J. 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Effects of temperature, time, and perfusion pressure in fibrillating hearts.</a> The Journal of Thoracic and Cardiovascular Surgery. 73 (1), 102-109 (1977).</li><li>von Planta, 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=Cardiopulmonary+resuscitation+in+the+rat.">Cardiopulmonary resuscitation in the rat.</a> Journal of Applied Physiology. 65 (6), 2641-2647 (1988).</li><li>Luo, X., 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=Ageing+increases+cardiac+electrical+remodelling+in+rats+and+mice+via+NOX4/ROS/CaMKII-mediated+calcium+signalling.">Ageing increases cardiac electrical remodelling in rats and mice via NOX4/ROS/CaMKII-mediated calcium signalling.</a> Oxidative Medicine and Cellular Longevity. 2022, 8538296 (2022).</li><li>Hohnloser, S., Weirich, J., Antoni, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+direct+current+on+the+electrical+activity+of+the+heart+and+on+its+susceptibility+to+ventricular+fibrillation.">Influence of direct current on the electrical activity of the heart and on its susceptibility to ventricular fibrillation.</a> Basic Research in Cardiology. 77 (3), 237-249 (1982).</li><li>Xie, J., 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=High-energy+defibrillation+increases+the+severity+of+postresuscitation+myocardial+dysfunction.">High-energy defibrillation increases the severity of postresuscitation myocardial dysfunction.</a> Circulation. 96 (2), 683-688 (1997).</li><li>Manoach, M., Netz, H., Erez, M., Weinstock, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ventricular+self-defibrillation+in+mammals:+Age+and+drug+dependence.">Ventricular self-defibrillation in mammals: Age and drug dependence.</a> Age and Ageing. 9 (2), 112-116 (1980).</li><li>Filippi, S., Gizzi, A., Cherubini, C., Luther, S., Fenton, F. 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이 프로토콜은 이전에 보고되지 않은 고립된 쥐 심장에서 장기 VF의 동물 모델을 설정합니다. 또한 이 연구에서는 다양한 전기 자극 조건을 비교했습니다. 본 연구는 심장 수술 중 심실세동 정지와 관련된 연구 모델을 제공한다.
모델의 성공률은 인력, 시간 및 경제적 비용과 관련된 매우 중요한 지표입니다. VF 모델에서 성공률에는 심장에서 VF를 유도할 수 있는지 여부와 제세...

심장 수술은 일반적으로 개흉술을 통해 수행되며 대동맥을 차단하고 심장을 정지시키기 위해 심정지 용액으로 관류합니다. 반복적인 심장 수술은 초기 수술보다 더 어려울 수 있으며, 합병증과 사망률이 더 높다 1,2,3. 또한, 기존의 정중 흉골 절개술 접근법은 흉골 뒤의 교량 혈관, 상행 대동맥, 우심실 및 기타 중요한 구조에 손상을 줄 수 있습니다. 결합 조직의 분리로 인한 광범위한 출혈, 흉골 상처 감염 및 흉골 절개술로 인한 흉골 골수염은 모두 가능한 합병증입니다. 광범위한 해부는 중요한 심장 구조에서 병변 및 출혈의 위험을 증가시킵니다.
최소 침습 심장 수술의 발달로 절개 부위가 작아지고 심정지가 때때로 이루어지기 어렵습니다. 심실세동(VF)4,5 하에서 반복적인 심장 수술은 안전하고 실현 가능하며 더 나은 심근 보호를 제공할 수 있습니다. 따라서 이 프로토콜은 최소 침습적 체외 순환을 통한 수술에서 VF 심정지 방법을 소개합니다. 심장은 VF 동안 효과적인 수축을 잃기 때문에 수술 중 상행 대동맥을 봉합하고 차단할 필요가 없으므로 절차가 간단 해집니다. 그러나 심장이 지속적으로 관류되더라도 장기간의 VF는 여전히 심장에 해로울 수 있습니다.
이 방법이 널리 사용됨에 따라 VF 동안 심장을 보호하는 방법에 대한 질문이 점점 더 중요해지고 있습니다. 이를 위해서는 장기 VF의 동물 모델을 사용한 광범위하고 심층적인 연구가 필요합니다. 과거에는 이 분야의 연구가 주로큰 동물을 사용했으며 6,7 외과의, 마취과 의사, 관류 의사 및 기타 연구자 간의 협력이 필요했습니다. 이러한 연구는 너무 오래 걸렸고 표본 크기가 작은 경우가 많았으며 연구는 일반적으로 기계 및 분자 평가보다는 심장 기능에 초점을 맞췄습니다. 현재까지 장기 VF 모델을 구축하기 위한 자세한 프로토콜을 보고한 연구는 없습니다.
따라서, 이 프로토콜은 Langendorff 장치를 사용하여 장기 VF 쥐 모델을 개발하는데 필요한 세부사항을 제공한다. 프로토콜은 간단하고 경제적이며 반복 가능하고 안정적입니다.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0 Non-absorbable suture</td>
			<td>Ethicon, Inc.</td>
			<td></td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>95% O2 + 5% CO2</td>
			<td>Beijing BeiYang United Gas Co., Ltd.&#160;</td>
			<td></td>
			<td>K-H buffer</td>
		</tr>
		<tr>
			<td>AcqKnowledge software</td>
			<td>BIOPAC Systems Inc.</td>
			<td>Version 4.2.1</td>
			<td>Software</td>
		</tr>
		<tr>
			<td>Automatic biochemistry analyzer</td>
			<td>Rayto Life and Analytical Sciences Co., Ltd.</td>
			<td>Chemray 800</td>
			<td>CK-MB assay</td>
		</tr>
		<tr>
			<td>BIOPAC research systems</td>
			<td>BIOPAC Systems Inc.</td>
			<td>MP150</td>
			<td>Hardware</td>
		</tr>
		<tr>
			<td>Blunt needle (20 G, TWLB)</td>
			<td>Tianjin Hanaco MEDICAL Co., Ltd.</td>
			<td>H-113AP-S</td>
			<td>Modified Langendorff perfusion system</td>
		</tr>
		<tr>
			<td>Calcium chloride</td>
			<td>Sinopharm Chemical Reagent Co.,Ltd</td>
			<td>10005861</td>
			<td>K-H buffer</td>
		</tr>
		<tr>
			<td>CK-MB assay kits&#160;</td>
			<td>Changchun Huili Biotech Co., Ltd.</td>
			<td>C060</td>
			<td>CK-MB assay</td>
		</tr>
		<tr>
			<td>Curved forcep</td>
			<td>Shanghai Medical Instrument (Group) Co., Ltd.</td>
			<td></td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>EDTA</td>
			<td>Sinopharm Chemical Reagent Co.,Ltd</td>
			<td>10009717</td>
			<td>K-H buffer</td>
		</tr>
		<tr>
			<td>Electrical stimulator</td>
			<td>BIOPAC Systems Inc.</td>
			<td>STEMISOC</td>
			<td>Hardware</td>
		</tr>
		<tr>
			<td>Filter</td>
			<td>Tianjin Hanaco MEDICAL Co., Ltd.</td>
			<td>H-113AP-S</td>
			<td></td>
		</tr>
		<tr>
			<td>Glucose</td>
			<td>Sinopharm Chemical Reagent Co.,Ltd</td>
			<td>63005518</td>
			<td>K-H buffer</td>
		</tr>
		<tr>
			<td>Heparin sodium</td>
			<td>Tianjin Biochem Pharmaceutical Co., Ltd.</td>
			<td>H120200505</td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>RWD Life Science Co.,LTD</td>
			<td>21082201</td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Magnesium sulfate</td>
			<td>Sinopharm Chemical Reagent Co.,Ltd</td>
			<td>20025118</td>
			<td>K-H buffer</td>
		</tr>
		<tr>
			<td>Needle electrodes</td>
			<td>BIOPAC Systems Inc.</td>
			<td>EL452</td>
			<td>Hardware</td>
		</tr>
		<tr>
			<td>Ophthalmic clamp</td>
			<td>Shanghai Medical Instrument (Group) Co., Ltd.</td>
			<td></td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Ophthalmic forceps</td>
			<td>Shanghai Medical Instrument (Group) Co., Ltd.</td>
			<td></td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Ophthalmic scissors</td>
			<td>Shanghai Medical Instrument (Group) Co., Ltd.</td>
			<td></td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Perfusion tube</td>
			<td>Tianjin Hanaco MEDICAL Co., Ltd.</td>
			<td>H-113AP-S</td>
			<td>Modified Langendorff perfusion system</td>
		</tr>
		<tr>
			<td>Potassium chloride</td>
			<td>Sinopharm Chemical Reagent Co.,Ltd</td>
			<td>10016318</td>
			<td>K-H buffer</td>
		</tr>
		<tr>
			<td>Sodium bicarbonate</td>
			<td>Sinopharm Chemical Reagent Co.,Ltd</td>
			<td>10018960</td>
			<td>K-H buffer</td>
		</tr>
		<tr>
			<td>Sodium chloride</td>
			<td>Sinopharm Chemical Reagent Co.,Ltd</td>
			<td>10019318</td>
			<td>K-H buffer</td>
		</tr>
		<tr>
			<td>Sodium dihydrogen phosphate dihydrate</td>
			<td>Sinopharm Chemical Reagent Co.,Ltd</td>
			<td>20040718</td>
			<td>K-H buffer</td>
		</tr>
		<tr>
			<td>Sprague-Dawley (SD) rats</td>
			<td>SPF (Beijing) biotechnology Co., Ltd.</td>
			<td>Male, 300-350g</td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Thermometer</td>
			<td>Jiangsu Jingchuang Electronics Co., Ltd.</td>
			<td>GSP-6</td>
			<td>Modified Langendorff perfusion system</td>
		</tr>
		<tr>
			<td>Tissueforceps</td>
			<td>Shanghai Medical Instrument (Group) Co., Ltd.</td>
			<td></td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Tissue scissors</td>
			<td>Shanghai Medical Instrument (Group) Co., Ltd.</td>
			<td></td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Toothed forceps</td>
			<td>Shanghai Medical Instrument (Group) Co., Ltd.</td>
			<td></td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Ventilator</td>
			<td>Chengdu Instrument Factory</td>
			<td>DKX-150</td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Water bath1</td>
			<td>Ningbo Scientz Biotechnology Co.,Ltd.</td>
			<td>SC-15</td>
			<td>Modified Langendorff perfusion system</td>
		</tr>
		<tr>
			<td>Water bath2</td>
			<td>Shanghai Yiheng Technology Instrument Co., Ltd.</td>
			<td>DK-8D</td>
			<td>Modified Langendorff perfusion system</td>
		</tr>
	</tbody>
</table>

a model of long-term ventricular fibrillation in isolated rat hearts

심실 세동 (VF)은 심장 환자에서 발생률이 높은 치명적인 부정맥이지만, 관류하에 VF 정지는 심장 수술 분야에서 수술 중 정지의 무시 된 방법입니다. 최근 심장 수술의 발전으로 관류 하에 장기간의 VF 연구에 대한 수요가 증가했습니다. 그러나 이 분야에는 만성 심실 세동의 간단하고 신뢰할 수 있으며 재현 가능한 동물 모델이 부족합니다. 이 프로토콜은 심외막의 교류(AC) 전기 자극을 통해 장기 VF를 유도합니다. VF를 유도하기 위해 장기 VF를 유도하기 위해 저전압 또는 고전압으로 연속 자극을 하고 자발적인 장기 VF를 유도하기 위해 저전압 또는 고전압으로 5분 동안 자극하는 등 다양한 조건을 사용했습니다. 다양한 조건의 성공률과 심근 손상 및 심장 기능 회복률을 비교했습니다. 그 결과 지속적인 저전압 자극이 장기 VF를 유도하고 5분의 저전압 자극이 경미한 심근 손상과 높은 심장 기능 회복률로 자발적인 장기 VF를 유도하는 것으로 나타났습니다. 그러나 저전압, 지속적으로 자극되는 장기 VF 모델은 성공률이 더 높았습니다. 고전압 자극은 VF 유도율이 높았지만 제세동 성공률이 낮고 심장 기능 회복이 불량하며 심각한 심근 손상을 보였습니다. 이러한 결과를 바탕으로 높은 성공률, 안정성, 신뢰성, 재현성, 심장 기능에 대한 낮은 영향 및 경미한 심근 손상을 위해 지속적인 저전압 심외막 AC 자극이 권장됩니다.

총 57마리의 랫트가 실험에 사용되었으며, 그 중 30마리가 포함 기준을 충족했습니다. 포함된 동물을 5개 그룹으로 나누었고, 각 그룹에 6마리의 동물이 있었습니다: 대조군(그룹 C), 저전압 연속 자극 장기 VF 그룹(그룹 LC), 고전압 연속 자극 장기 VF 그룹(그룹 HC), 저전압 유도 자발적 장기 VF 그룹(그룹 LI) 및 고전압 유도 자발적 장기 VF 그룹(그룹 HI). 각 그룹의 실험 과정은 그림 2</stron...

Watch this Scientific Journal Video about A Model of Long-Term Ventricular Fibrillation in Isolated Rat Hearts at JoVE.com

A Model of Long-Term Ventricular Fibrillation in Isolated Rat Hearts

이 프로토콜은 저전압 교류를 통한 지속적인 자극에 의해 유도된 쥐 심장의 장기 심실 세동 모델을 제시합니다. 이 모델은 성공률이 높고 안정적이고 신뢰할 수 있으며 재현 가능하며 심장 기능에 미치는 영향이 적고 경미한 심근 손상만 유발합니다.

고립 된 쥐 심장에서 장기 심실 세동의 모델

Ventricular fibrillation (VF) is a fatal arrhythmia with a high incidence in cardiac patients, but VF arrest under perfusion is a neglected method of ...

이 프로토콜은 Langendorff 장치를 사용하여 장기 심실 세동 쥐 모델을 개발하기 위한 자세한 요구 사항을 제공합니다. 그것은 작은 동물 모델에서 장기 심실 세동의 간격을 채 웁니다. 기술은 간단하고 경제적이며 반복 가능하고 안정적입니다.이 기술은 심장 수술 세션 및 수술 분야의 특정 임상 상황에서 수행되는 관류 하의 심실 세동 정지 연구에 사용될 수 있습니다. 시작하려면 증류수에 118 밀리몰 염화나트륨, 4.7 밀리몰 염화칼륨, 1.2 밀리몰 염화마그네슘, 1.2 밀리몰 인산이수소나트륨, 1.8 밀리몰 염화칼슘, 25 밀리몰 중탄산나트륨, 11.1 밀리몰 포도당 및 0.5 밀리몰 EDTA를 증류수에 첨가하여 Krebs-Henseleit 또는 KH 완충액을 준비합니다. 그런 다음 수정된 Langendorff 관류 시스템을 준비합니다.약 80mm의 수은 압력에서 95% 산소 및 5% 이산화탄소로 KH 완충액이 들어 있는 플라스크에 지속적으로 가스를 공급합니다. 관류 튜브의 한쪽 끝을 KH 버퍼에 넣고 관류 튜브의 중간을 수조에 통과시킨 다음 관류 튜브의 다른 쪽 끝에 뭉툭한 20게이지 바늘을 부착합니다. 와이어 스탠드에 바늘을 매달아 놓은 후 관류 시스템 끝에서 KH 버퍼의 온도가 섭씨 37도가되도록 수조의 온도를 조정합니다.생리학적 신호 레코더를 사용하여 모든 아날로그 신호를 디지털화하고 기록할 수 있습니다. 두 개의 스테인리스 스틸 바늘 전극을 사용하여 양극성 심전도 또는 ECG를 기록하고 전기 자극을 위해 두 개의 스테인리스 스틸 바늘 전극을 사용합니다. 4개의 전극 중 한쪽 끝을 생리적 신호 기록기에 연결하고 다른 쪽 끝을 장치에 부착한 후 심장이 위치할 영역에 가깝게 연결합니다.그런 다음 랩톱 소프트웨어를 사용하여 양극성 ECG 및 혈역학적 매개변수를 자동으로 인식, 조정 및 기록합니다. 전기 자극기 매개변수를 저전압 그룹이 30볼트를 수신하고 고전압 그룹이 2볼트를 수신하는 6Hz 교류로 설정합니다. 자궁 경부 절제술과 기관 삽관 후 인공 호흡기에 연결된 마취 된 쥐를 가지고 톱니 겸자로 xiphoid 과정에서 피부를 들어 올리고 조직 가위로 피부에 3 센티미터의 가로 절개를합니다.피부와 갈비뼈 절개 부위를 V자 모양으로 양쪽 겨드랑이까지 확장합니다. 무딘 절개를 사용하여 상완 간부 줄기를 주변 조직에서 분리하십시오. 그런 다음 심장의 제거를 용이하게하기 위해 구부러진 집게로 상완 뇌 줄기를 고정하십시오.즉시 섭씨 0도에서 4도까지 KH 완충액이 든 페트리 접시에 심장을 담그고 잔류 혈액을 씻어내고 펌핑합니다. 심장을 두 번째 페트리 접시로 옮깁니다. 중복 조직을 잘라내고 대동맥을 확인하십시오.두 개의 안과용 집게를 사용하여 대동맥을 들어 올리고 대동맥을 Langendorff 장치의 무딘 바늘에 삽입합니다. 그런 다음 조수의 도움을 받아 0 봉합사로 매듭을 묶습니다. 관류 유량 조절기를 켭니다.승모판을 통해 풍선을 좌심실로 밀어 넣습니다. 풍선을 증류수로 채워 이완기 말 수은압을 5-10mm로 만듭니다. ECG와 전기 자극 전극을 심장에 연결합니다.섭씨 37도로 유지되는 재킷 유리 챔버의 중앙에 심장을 놓습니다. 챔버 내부에서 심장이 20분 동안 평형을 이루도록 합니다. 그런 다음 수조 온도를 조정하여 재킷 유리 챔버 내의 온도를 섭씨 30도로 유지합니다.온도가 원하는 수준에 도달하면 랩톱 소프트웨어의 전기 자극 스위치를 활성화하십시오. 동물이 지속적으로 자극되는 장기 심실 세동 또는 VF 그룹의 일부인 경우 90 분 동안 전기 자극을 허용하십시오. VF 90분 후 전극을 사용하여 0.1줄의 직류 제세동을 제공합니다.동시에, 수조 온도를 조절하여 재킷 유리 챔버 내의 온도가 섭씨 37도까지 10분 동안 천천히 상승할 수 있도록 합니다. 제세동 후 심장이 60분 동안 뛰도록 한 다음 약 섭씨 37도에서 10% 염화칼륨으로 천천히 관류하여 박동을 멈춥니다. 크레아틴 키나아제 또는 CK-MB 분석 및 조직학적 분석을 위해 심장을 제거합니다.VF의 비율, 제세동의 성공률 및 VF 모델의 성공률이 여기에 표시됩니다. Group LC와 Group HC는 지속적인 전기 자극을 받아 VF가 100% 성공률로 발생했습니다. 그러나 그룹 HC는 제세동 성공률이 낮았습니다.5분 후에 전기자극을 끈 LI군과 HI군은 VF 비율이 달랐으나 LC군과 HC군에 비해 두 그룹 모두 VF 비율이 더 느렸다. 그룹 LC와 그룹 LI 모두 제세동 성공률이 더 높았습니다. 그러나 전반적으로 그룹 LC는 모델 성공률이 가장 높았고 그룹 LI는 모델 성공률이 낮았습니다. 심박수 또는 HR, 관상 동맥 흐름 또는 CF, 좌심실 압력 차이 또는 LVPD 회복률이 여기에 표시됩니다.그룹 C의 혈역학은 실험 동안 안정적으로 유지되었으며 HR, CF 및 LVPD에서 약간의 감소를 보였습니다. 저전압 유도 VF를 가진 두 그룹은 유사한 성능과 우수한 회복률을 보였습니다. HR과 LVPD는 그룹 C에 비해 이들 그룹에서 유의한 차이가 없었지만 CF의 회복률은 그룹 C.In 보다 유의하게 우수했으며, 고전압으로 유도된 두 그룹의 혈역학적 회복률은 장기 VF로 유도되지 않았고 고전압 연속 자극 장기 VF 그룹은 최악의 회복률을 보였다.관상동맥 삼출액의 분석은 CK-MB 수준이 두 고전압 그룹 모두에서 더 높은 것으로 나타났습니다. 두 저전압 그룹 사이에는 차이가 발견되지 않았으며, 그룹 C.헤마톡실린 및 에오신 염색은 그룹 HC에서 전극 연소 영역을 나타냈다. 이 프로토콜은 심실 세동 정지 및 심혈관 수술의 관류와 관련된 연구에 적합합니다.

a-model-of-long-term-ventricular-fibrillation-in-isolated-rat-hearts

Research

JoVE Journal

Medicine

Assessment of Cardiac Function and Energetics in Isolated Mouse Hearts Using 31P NMR Spectroscopy

Bioengineered mouse models have become powerful research tools in determining causal relationships between molecular alterations and models of cardiovascular disease. Although molecular biology is necessary in identifying key changes in the signaling pathway, it is not a surrogate for functional significance. While physiology can provide answers to the question of function, combining physiology with biochemical assessment of metabolites in the intact, beating heart allows for a complete picture of cardiac function and energetics. For years, our laboratory has utilized isolated heart perfusions combined with nuclear magnetic resonance (NMR) spectroscopy to accomplish this task. Left ventricular function is assessed by Langendorff-mode isolated heart perfusions while cardiac energetics is measured by performing 31P magnetic resonance spectroscopy of the perfused hearts. With these techniques, indices of cardiac function in combination with levels of phosphocreatine and ATP can be measured simultaneously in beating hearts. Furthermore, these parameters can be monitored while physiologic or pathologic stressors are instituted. For example, ischemia/reperfusion or high workload challenge protocols can be adopted. The use of aortic banding or other models of cardiac pathology are apt as well. Regardless of the variants within the protocol, the functional and energetic significance of molecular modifications of transgenic mouse models can be adequately described, leading to new insights into the associated enzymatic and metabolic pathways. Therefore, 31P NMR spectroscopy in the isolated perfused heart is a valuable research technique in animal models of cardiovascular disease.

Assessment of Cardiac Function and Energetics in Isolated Mouse Hearts Using 31P NMR Spectroscopy

Langendorff-mode isolated heart perfusion, in conjunction with 31P NMR spectroscopy, combines the fields of biochemistry and physiology into one experiment. The protocol allows for the dynamic measurement of high energy phosphate content and turnover in the heart while concurrently monitoring physiologic function. When performed correctly, this is a valuable technique in the assessment of cardiac energetics.

를 사용하여 절연 마우스 마음에 심장 기능 및 에너 지학 평가 31 P NMR 분광학

Bioengineered mouse models have become powerful research tools in determining causal relationships between molecular alterations and models of ...

연구

의학

NADH Fluorescence Imaging of Isolated Biventricular Working Rabbit Hearts

Since its inception by Langendorff1, the isolated perfused heart remains a prominent tool for studying cardiac physiology2. However, it is not well-suited for studies of cardiac metabolism, which require the heart to perform work within the context of physiologic preload and afterload pressures. Neely introduced modifications to the Langendorff technique to establish appropriate left ventricular (LV) preload and afterload pressures3. The model is known as the isolated LV working heart model and has been used extensively to study LV performance and metabolism4-6. This model, however, does not provide a properly loaded right ventricle (RV). Demmy et al. first reported a biventricular model as a modification of the LV working heart model7, 8. They found that stroke volume, cardiac output, and pressure development improved in hearts converted from working LV mode to biventricular working mode8. A properly loaded RV also diminishes abnormal pressure gradients across the septum to improve septal function. Biventricular working hearts have been shown to maintain aortic output, pulmonary flow, mean aortic pressure, heart rate, and myocardial ATP levels for up to 3 hours8.
When studying the metabolic effects of myocardial injury, such as ischemia, it is often necessary to identify the location of the affected tissue. This can be done by imaging the fluorescence of NADH (the reduced form of nicotinamide adenine dinucleotide)9-11, a coenzyme found in large quantities in the mitochondria. NADH fluorescence (fNADH) displays a near linearly inverse relationship with local oxygen concentration12 and provides a measure of mitochondrial redox state13. fNADH imaging during hypoxic and ischemic conditions has been used as a dye-free method to identify hypoxic regions14, 15 and to monitor the progression of hypoxic conditions over time10.
The objective of the method is to monitor the mitochondrial redox state of biventricular working hearts during protocols that alter the rate of myocyte metabolism or induce hypoxia or create a combination of the two. Hearts from New Zealand white rabbits were connected to a biventricular working heart system (Hugo Sachs Elektronik) and perfused with modified Krebs-Henseleit solution16 at 37 &deg;C. Aortic, LV, pulmonary artery, and left &amp; right atrial pressures were recorded. Electrical activity was measured using a monophasic action potential electrode. To image fNADH, light from a mercury lamp was filtered (350&plusmn;25 nm) and used to illuminate the epicardium. Emitted light was filtered (460&plusmn;20 nm) and imaged using a CCD camera. Changes in the epicardial fNADH of biventricular working hearts during different pacing rates are presented. The combination of the heart model and fNADH imaging provides a new and valuable experimental tool for studying acute cardiac pathologies within the context of realistic physiological conditions.

The objective is to monitor the mitochondrial redox state of isolated hearts within the context of physiologic preload and afterload pressures. A biventricular working rabbit heart model is presented. High spatiotemporal resolution fluorescence imaging of NADH is used to monitor the mitochondrial redox state of epicardial tissue.

절연 Biventricular의 NADH 형광 이미징은 토끼 하트 워킹

Since its inception by Langendorff1, the isolated perfused heart remains a prominent tool for studying cardiac physiology2. However, it is not well-suited ...

Reduction in Left Ventricular Wall Stress and Improvement in Function in Failing Hearts using Algisyl-LVR

Injection of Algisyl-LVR, a treatment under clinical development, is intended to treat patients with dilated cardiomyopathy. This treatment was recently used for the first time in patients who had symptomatic heart failure. In all patients, cardiac function of the left ventricle (LV) improved significantly, as manifested by consistent reduction of the LV volume and wall stress. Here we describe this novel treatment procedure and the methods used to quantify its effects on LV wall stress and function.
Algisyl-LVR is a biopolymer gel consisting of Na+-Alginate and Ca2+-Alginate. The treatment procedure was carried out by mixing these two components and then combining them into one syringe for intramyocardial injections. This mixture was injected at 10 to 19 locations mid-way between the base and apex of the LV free wall in patients.
Magnetic resonance imaging (MRI), together with mathematical modeling, was used to quantify the effects of this treatment in patients before treatment and at various time points during recovery. The epicardial and endocardial surfaces were first digitized from the MR images to reconstruct the LV geometry at end-systole and at end-diastole. Left ventricular cavity volumes were then measured from these reconstructed surfaces.
Mathematical models of the LV were created from these MRI-reconstructed surfaces to calculate regional myofiber stress. Each LV model was constructed so that 1) it deforms according to a previously validated stress-strain relationship of the myocardium, and 2) the predicted LV cavity volume from these models matches the corresponding MRI-measured volume at end-diastole and end-systole. Diastolic filling was simulated by loading the LV endocardial surface with a prescribed end-diastolic pressure. Systolic contraction was simulated by concurrently loading the endocardial surface with a prescribed end-systolic pressure and adding active contraction in the myofiber direction. Regional myofiber stress at end-diastole and end-systole was computed from the deformed LV based on the stress-strain relationship.

This article describes procedures for implanting a novel hydrogel in failing hearts and quantifying its effect on left ventricular wall stress and function. These procedures have been successfully applied in dogs and humans.

Algisyl-LVR을 사용하여 마음을 실패의 기능에서 왼쪽 심실 벽 스트레스와 개선의 감소

Injection of  Algisyl-LVR, a treatment under clinical development, is intended to treat  patients with dilated cardiomyopathy. This treatment was recently ...

Method of Isolated Ex Vivo Lung Perfusion in a Rat Model: Lessons Learned from Developing a Rat EVLP Program

The number of acceptable donor lungs available for lung transplantation is severely limited due to poor quality. Ex-Vivo Lung Perfusion (EVLP) has allowed lung transplantation in humans to become more readily available by enabling the ability to assess organs and expand the donor pool. As this technology expands and improves, the ability to potentially evaluate and improve the quality of substandard lungs prior to transplant is a critical need. In order to more rigorously evaluate these approaches, a reproducible animal model needs to be established that would allow for testing of improved techniques and management of the donated lungs as well as to the lung-transplant recipient. In addition, an EVLP animal model of associated pathologies, e.g., ventilation induced lung injury (VILI), would provide a novel method to evaluate treatments for these pathologies. Here, we describe the development of a rat EVLP lung program and refinements to this method that allow for a reproducible model for future expansion. We also describe the application of this EVLP system to model VILI in rat lungs. The goal is to provide the research community with key information and &#8220;pearls of wisdom&#8221;/techniques that arose from trial and error and are critical to establishing an EVLP system that is robust and reproducible.

Method of Isolated Ex Vivo Lung Perfusion in a Rat Model: Lessons Learned from Developing a Rat EVLP Program

Ex-Vivo Lung Perfusion (EVLP) has allowed lung transplantation in humans to become more readily available by enabling the ability to assess organs and expand the donor pool. Here, we describe the development of a rat EVLP program and refinements that allow for a reproducible model for future expansion.

고립의 방법<em&gt; 전의 VIVO</em쥐 모델에서&gt; 폐 관류 : 쥐 EVLP 프로그램 개발에서 교훈을

The number of acceptable donor lungs available for lung transplantation is severely limited due to poor quality. Ex-Vivo Lung Perfusion (EVLP) has allowed ...

A Rat Model of Ventricular Fibrillation and Resuscitation by Conventional Closed-chest Technique

A rat model of electrically-induced ventricular fibrillation followed by cardiac resuscitation using a closed chest technique that incorporates the basic components of cardiopulmonary resuscitation in humans is herein described. The model was developed in 1988 and has been used in approximately 70 peer-reviewed publications examining a myriad of resuscitation aspects including its physiology and pathophysiology, determinants of resuscitability, pharmacologic interventions, and even the effects of cell therapies. The model featured in this presentation includes: (1) vascular catheterization to measure aortic and right atrial pressures, to measure cardiac output by thermodilution, and to electrically induce ventricular fibrillation; and (2) tracheal intubation for positive pressure ventilation with oxygen enriched gas and assessment of the end-tidal CO2. A typical sequence of intervention entails: (1) electrical induction of ventricular fibrillation, (2) chest compression using a mechanical piston device concomitantly with positive pressure ventilation delivering oxygen-enriched gas, (3) electrical shocks to terminate ventricular fibrillation and reestablish cardiac activity, (4) assessment of post-resuscitation hemodynamic and metabolic function, and (5) assessment of survival and recovery of organ function. A robust inventory of measurements is available that includes &#8211; but is not limited to &#8211; hemodynamic, metabolic, and tissue measurements. The model has been highly effective in developing new resuscitation concepts and examining novel therapeutic interventions before their testing in larger and translationally more relevant animal models of cardiac arrest and resuscitation.

This article describes a rat model of electrically-induced ventricular fibrillation and resuscitation by chest compression, ventilation, and delivery of electrical shocks that simulates an episode of sudden cardiac arrest and conventional cardiopulmonary resuscitation. The model enables gathering insights on the pathophysiology of cardiac arrest and exploration of new resuscitation strategies.

기존의 폐쇄 가슴 기술에 의해 쥐의 심실 세동의 모델 및 소생

A rat model of electrically-induced ventricular fibrillation followed by cardiac resuscitation using a closed chest technique that incorporates the basic ...

Induction and Assessment of Ischemia-reperfusion Injury in Langendorff-perfused Rat Hearts

The biochemical events surrounding ischemia reperfusion injury in the acute setting are of great importance to furthering novel treatment options for myocardial infarction and cardiac complications of thoracic surgery. The ability of certain drugs to precondition the myocardium against ischemia reperfusion injury has led to multiple clinical trials, with little success. The isolated heart model allows acute observation of the functional effects of ischemia reperfusion injury in real time, including the effects of various pharmacological interventions administered at any time-point before or within the ischemia-reperfusion injury window. Since brief periods of ischemia can precondition the heart against ischemic injury, in situ aortic cannulation is performed to allow for functional assessment of non-preconditioned myocardium. A saline filled balloon is placed into the left ventricle to allow for real-time measurement of pressure generation. Ischemic injury is simulated by the cessation of perfusion buffer flow, followed by reperfusion. The duration of both ischemia and reperfusion can be modulated to examine biochemical events at any given time-point. Although the Langendorff isolated heart model does not allow for the consideration of systemic events affecting ischemia and reperfusion, it is an excellent model for the examination of acute functional and biochemical events within the window of ischemia reperfusion injury as well as the effect of pharmacological intervention on cardiac pre- and postconditioning. The goal of this protocol is to demonstrate how to perform in situ aortic cannulation and heart excision followed by ischemia/reperfusion injury in the Langendorff model.

The isolated rat heart is an enduring model for ischemia reperfusion injury. Here, we describe the process of harvesting the beating heart from a rat via in situ aortic cannulation, Langendorff perfusion of the heart, simulated ischemia-reperfusion injury, and infarct staining to confirm the extent of ischemic insult.

랑겐 돌프 - 관류 쥐 마음에 유도 및 허혈 - 재관류 손상의 평가

The biochemical events surrounding ischemia reperfusion injury in the acute setting are of great importance to furthering novel treatment options for ...

Surgical Placement of Catheters for Long-term Cardiovascular Exercise Testing in Swine

This protocol describes the surgical procedure to chronically instrument swine and the procedure to exercise swine on a motor-driven treadmill. Early cardiopulmonary dysfunction is difficult to diagnose, particularly in animal models, as cardiopulmonary function is often measured invasively, requiring anesthesia. As many anesthetic agents are cardiodepressive, subtle changes in cardiovascular function may be masked. In contrast, chronic instrumentation allows for measurement of cardiopulmonary function in the awake state, so that measurements can be obtained under quiet resting conditions, without the effects of anesthesia and acute surgical trauma. Furthermore, when animals are properly trained, measurements can also be obtained during graded treadmill exercise.
Flow probes are placed around the aorta or pulmonary artery for measurement of cardiac output and around the left anterior descending coronary artery for measurement of coronary blood flow. Fluid-filled catheters are implanted in the aorta, pulmonary artery, left atrium, left ventricle and right ventricle for pressure measurement and blood sampling. In addition, a 20 G&#160;catheter is positioned in the anterior interventricular vein to allow coronary venous blood sampling.
After a week of recovery, swine are placed on a motor-driven treadmill, the catheters are connected to pressure and flow meters, and swine are subjected to a five-stage progressive exercise protocol, with each stage lasting 3 min. Hemodynamic signals are continuously recorded and blood samples are taken during the last 30 sec of each exercise stage.
The major advantage of studying chronically instrumented animals is that it allows serial assessment of cardiopulmonary function, not only at rest but also during physical stress such as exercise. Moreover, cardiopulmonary function can be assessed repeatedly during disease development and during chronic treatment, thereby increasing statistical power and hence limiting the number of animals required for a study.

Here we present a protocol to assess cardiopulmonary function in awake swine, at rest and during graded treadmill exercise. Chronic instrumentation allows for repeated hemodynamic measurements uninfluenced by cardiodepressive anesthetic agents.

돼지의 장기 심장 혈관 운동 테스트를위한 카테터의 외과 배치

This protocol describes the surgical procedure to chronically instrument swine and the procedure to exercise swine on a motor-driven treadmill. Early ...

Long-term Blood Pressure Measurement in Freely Moving Mice Using Telemetry

During the development of new vasoactive agents, arterial blood pressure monitoring is crucial for evaluating the efficacy of the new proposed drugs. Indeed, research focusing on the discovery of new potential therapeutic targets using genetically altered mice requires a reliable, long-term assessment of the systemic arterial pressure variation. Currently, the gold standard for obtaining long-term measurements of blood pressure in ambulatory mice uses implantable radio-transmitters, which require&#160;artery cannulation. This technique eliminates the need for tethering, restraining, or anesthetizing the animals which introduce stress and artifacts during data sampling. However, arterial blood pressure monitoring in mice via catheterization can be rather challenging due to the small size of the arteries. Here we present a step-by-step guide to illustrate the crucial key passages for a successful subcutaneous implantation of radio-transmitters and carotid artery cannulation in mice. We also include examples of long-term blood pressure activity taken from freely moving mice after a period of post-surgery recovery. Following this procedure will allow reliable direct blood pressure recordings from multiple animals simultaneously.

The goal of this protocol is to assess systemic blood pressure in conscious freely moving mice using implantable radio-telemetry devices.

텔레 메 트리를 사용하여 자유롭게 이동 마우스의 장기 혈압 측정

During the development of new vasoactive agents, arterial blood pressure monitoring is crucial for evaluating the efficacy of the new proposed drugs. ...

The Inverted Heart Model for Interstitial Transudate Collection from the Isolated Rat Heart

The present protocol describes a unique approach that enables the collection of cardiac transudate (CT) from the isolated, saline-perfused rat heart. After isolation and retrograde perfusion of the heart according to the Langendorff technique, the heart is inverted into an upside-down position and is mechanically stabilized by a balloon catheter inserted into the left ventricle. Then, a thin latex cap &#8211; previously cast to match the average size of the rat heart &#8211; is placed over the epicardial surface. The outlet of the latex cap is connected to silicon tubing, with the distal opening 10 cm below the base level of the heart, creating slight suction. CT continuously produced on the epicardial surface is collected in ice-cooled vials for further analysis. The rate of CT formation ranged from 17 to 147 &#181;L/min (n = 14) in control and infarcted hearts, which represents 0.1-1% of the coronary venous effluent perfusate. Proteomic analysis and high performance liquid chromatography (HPLC) revealed that the collected CT contains a wide spectrum of proteins and purinergic metabolites.

This protocol describes a method to collect cardiac interstitial fluid from the isolated, perfused rat heart. To physically separate interstitial transudate from coronary venous effluent perfusate, the Langendorff perfused heart is inverted, and the transudate (interstitial fluid) formed on the cardiac surface is collected using a soft latex cap.

고립 된 랫트 심장으로부터의 간질과 투과 물 수집을위한 역전 된 심장 모델

The present protocol describes a unique approach that enables the collection of cardiac transudate (CT) from the isolated, saline-perfused rat heart. ...

Standardized Model of Ventricular Fibrillation and Advanced Cardiac Life Support in Swine

Cardiopulmonary resuscitation after cardiac arrest, independent of its origin, is a regularly encountered medical emergency in hospitals as well as preclinical settings. Prospective randomized trials in human subjects are difficult to design and ethically ambiguous, which results in a lack of evidence-based therapies. The model presented in this report represents one of the most common causes of cardiac arrests, ventricular fibrillation, in a standardized setting in a large animal model. This allows for reproducible observations and various therapeutic interventions under clinically accurate conditions, hence facilitating the generation of better evidence and eventually the potential for improved medical treatment.

Cardiopulmonary resuscitation and defibrillation are the only effective therapeutic options during cardiac arrest caused by ventricular fibrillation. This model presents a standardized regimen to induce, assess, and treat this physiological state in a porcine model, thus providing a clinical approach with various opportunities for data collection and analysis.

돼지의 심실 세동 및 고급 심장 생명 지원의 표준화 모델

Cardiopulmonary resuscitation after cardiac arrest, independent of its origin, is a regularly encountered medical emergency in hospitals as well as ...