Marc Wozniak para o uso do Departamento de celular e Developmental Biology videografia equipamento. Universidade Vanderbilt imagens de células recurso compartilhado. Este trabalho é apoiado pela AHA concessão 12PRE10950005 de ERP, AHA concessão 11GRNT7690040 a DMB, NIH concessão R01 HL037675 a DMB. DMB é o Presidente Gladys P. Stahlman no Cardiovascular Research.

Certifique-se de todos os procedimentos que envolvem animais são aprovados pelo uso de animais apropriados e cuidados com o corpo. 1 Prepare Banco Buffers em adiantado <ol><li> Prepare 2 L estoque de Ca2 + de Tyrode livre (Tabela 1). Ajustar o pH para 7,4 com NaOH. </li><li> Prepare 2 L estoque 1,2 mM de Ca2 + Tyrode (Tabela 2). Ajustar o pH para 7,4 com NaOH. </li></ol> 2 No dia do experimento, Prepare Perfusão, Transferência e Digestão Buffers <ol><li> Prepare tampão de perfusão de 150 ml em Ca 2 + de Tyrode livre (Tabela 3) e filtrar através de um filtro de 0,2 m. </li><li> Preparar 35 ml de Ca 2 + transferência livre &quot;Tampão A&quot; (Tabela 4) e 25 ml de Ca2 + contendo &quot;Tampão B&quot; (Tabela 5). Filtre através de um filtro a cada 0,2 m. </li><li> Preparar soluções de 00,06, 0,24, 0,6, e 1,2 mM de Ca 2 + por mistura de tampão A e B por Tabela 6. </li><li> Preparar um tampão de digestão de 25 ml por dissolução de enzimas de digestão em 25 ml de tampão de perfusão (Tabela 7) com base no peso corporal (BW) do rato. Filtrar através de um filtro de 0,2 m antes da utilização. </li></ol> 3. Setup Experimental <ol><li> Montar um aparelho de Langendorff o fluxo constante, disponíveis comercialmente ou através de um bomba peristáltica, tubagem, e um permutador de calor da bobina para permitir uma taxa de fluxo de 3 mL / min de perfusato aquecida a 37 ° C. Um esquema simples é fornecida na revisão de 2011 por Bell, et al 18. </li><li> Ajuste temperatura do banho de circulação de água (~ 47 ° C) do aparelho de Langendorff de modo que a partir da saída da cânula é de 37 ° C a uma taxa de fluxo de 3 ml / min. </li><li> Executar etanol a 70%, através do sistema de perfusão durante 15 min, seguido de 100 ml de tipo I de água ultrapura. Tampão de perfusão Executar através do system durante 5 minutos, enquanto a eliminação de bolhas de ar. </li><li> Esterilizar todos os instrumentos cirúrgicos com um método desejado. </li><li> Criar uma cânula, anexando uma peça curta (cerca de 3 mm) de tubagem PE-50 para a ponta de um adaptador Luer 23 L-topo. Ponta de tubo de calor para criar um rebordo ao longo da aorta que vai ser posicionado. </li></ol> 4. Cardiomyocyte Isolamento <ol><li> Injectar rato com 0,2 mL de solução de heparina (1000 IU / ml), por meio de injecção intraperitoneal. </li><li> Após 5 min, anestesiar rato com isofluorano. Quando totalmente anestesiados (sem resposta à forte pitada pé), spray peito com etanol 70%. Abra o peito, rapidamente extirpar do coração, tomando cuidado para não danificar a aorta, e coloque em 4 ° C tampão de perfusão. Use uma pinça curva para agarrar e levantar sob o coração. Isso cria espaço para cortar os anexos por trás do coração com uma tesoura fina. </li><li> Canular coração, segurando gentilmente a borda da aorta com dois pares de uma pinça fina e puxando cuidadosamente o opening da aorta ao longo da borda da cânula. Assegurar a ponta da cânula não está para além da válvula aórtica no ventrículo e, como isso vai inibir a perfusão do coração através das artérias coronárias. </li><li> Fixar a aorta à cânula por amarrar um laço de seda de sutura 5-0 em torno da aorta imediatamente acima do bordo da cânula. </li><li> Nota: Os passos 4.2 através de 4.4 deve ser concluída o mais rapidamente possível para a digestão de melhor qualidade. </li><li> Nota: O coração pode ser suspenso directamente sobre a cânula já ligado ao aparelho de Langendorff com fluir tampão de perfusão. No entanto, pendurando o coração para uma cânula ligada a uma pequena seringa de tampão de perfusão sob um microscópio de dissecção foi encontrada para ser mais bem sucedido. Isso permite que uma pequena quantidade de tampão de perfusão a ser empurrado através, prestando atenção para limpeza de artérias coronárias e garantindo coração está firmemente conectado à cânula. A cânula é então pendurado na Langendorff com tampão de corrida de perfusão. </li><li> Perfundiro coração com Ca2 + livre tampão de perfusão a um caudal de 3 ml / min durante 2-3 min. </li><li> Mudar para a enzima tampão de digestão e perfuse por 7-10 min, o coração vai se tornar mais suave e de cor mais clara. </li><li> Nota: O tempo de digestão pode ser ajustada com base na atividade enzimática e tamanho do coração. </li><li> Uma vez que o coração é palpável flácido, retire o coração da cânula e coloque em um prato p60 estéril com tampão A (Ca2 + buffer de transferência gratuita). </li><li> Remover átrios e grandes vasos. Remover ventrículo direito, se desejar. Com uma pinça, separar o ventrículo em pedaços pequenos. Pipeta várias vezes com uma pipeta esterilizada de 5 ml de transferência para dispersar ainda mais as células. </li><li> Filtra-se a suspensão de células para um tubo cónico de 50 ml através de um filtro de 250 um de malha de nylon. </li><li> Permitir que a suspensão para sedimentar durante cerca de 10 min. </li><li> Transferir a pelota na solução de Ca 2 + de 0,06 mM. Permitir que as células sedimentar durante 10 minutos. Células saudáveis ​​irá agregar, enquanto a maioria das células mortas vão flutuar. </li&gt; <li> Aspirar o sobrenadante, e transferir o sedimento para o Ca 2 + solução 0,24 mM. </li><li> Repetir 10 min de incubação, a aspiração, e transferir-se através dos restantes dois Ca 2 + soluções até que as células estão na solução 1,2 mM. Neste ponto, a maioria das células deverá ser em forma de haste miócitos. </li></ol> 5. medição na contração e cálcio Transitórios <ol><li> Nota: Tanto a contratilidade e transientes de cálcio podem ser medidos simultaneamente. </li><li> Prepare Fura-2 AM solução por ressuspensão em DMSO anidro para uma concentração de 1 ug / uL. Solução de Fura-2 AM pode ser armazenado num exsicador a -20 ° C. </li><li> Carga 1 ml de células em suspensão com 1 ml Fura-2 AM. Permitir que as células se sentar no escuro 10 min, em seguida, aspirar o sobrenadante. Lavar duas vezes com uma solução de Ca2 + de Tyrode, permitindo que as células de granulação no escuro durante 10 min entre as lavagens. </li><li> Coloque uma lamela de vidro em uma inserção de estágio que permite pe aquecidarfusion / aspiração e eletrodo de andar com um estimulador campo miócitos. Coloque inserção fase em microscópio invertido configurado para medição de fluorescência, adicionando uma gota de óleo de lente se utilizando uma objectiva de imersão em óleo. </li><li> Configure perfusão gravidade aquecida com solução 1,2 mM de Ca2 + de Tyrode tão solução no palco atinge 37 ° C. Anexar aspiração a vácuo. Anexar eletrodos. </li><li> Ligue o sistema de microscópio, e abrir a fluorescência e aquisição de dados dimensionamento celular software ratiometric. </li><li> Adicione algumas gotas de células carregadas Fura-02:00 à inserção fase, bloqueando momentaneamente perfusão permitir que as células saudáveis ​​para resolver. </li><li> Use objectiva de 40x de localizar celular desejado. Uma célula saudável deve ser em forma de haste e não contrair espontaneamente. É visível e uniformemente contrato deve quando a célula é estimulada em 5-20 V. </li><li> Nota: a análise fisiológica requer uma digestão de alta qualidade. É possível ter células que parecem saudáveis, mas não fazer pa<html> ce bem para análise fisiológica. Protocolo de digestão pode exigir refinamento para obter alta qualidade, os miócitos saudáveis. Além disso, corações mutantes ou doentes podem necessitar de modificações no protocolo. </li><li> Ajustar a rotação da lente e abertura mudança tão célula desejada está alinhada horizontalmente na tela e no fundo não é visível. </li><li> Alinhe bares detecção de bordas a cada final de miócitos e ajustar limite. Alinhar detecção sarcómero sobre uma porção de célula com sarcómeros uniformes. Quanto mais tempo você pode fazer este bar, mais preciso será o modelo matemático de comprimento do sarcômero será, desde que ele não esteja em duas populações de sarcômeros. </li><li> Células ritmo em 2 Hz e 5-20 V para 10-15 segundos antes de gravar. </li><li> Rastreamento Record. A luz ambiente deve ser minimizado para a melhor gravação de cálcio transiente. </li></ol> 6 Análise <ol><li> Analisar os traços usando fluorescência ratiometric e dimensionamento de células software de aquisição de dados. </li></ol>título &quot;&gt; 7. Estudos Futuros <ol><li> Este protocolo prevê excesso de células que podem ser usados ​​para uma variedade de outras experiências, incluindo: fixação e imunomarcação, avaliando os efeitos diretos da droga, a cultura de curto prazo, e microscopia de força atômica. </li></ol>

<ol>
	<li>Babick, A. P., Dhalla, N. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+Subcellular+Remodeling+in+Cardiac+Dysfunction+due+to+Congestive+Heart+Failure.">Role of Subcellular Remodeling in Cardiac Dysfunction due to Congestive Heart Failure.</a> Medical Principles and Practice. 16, 81-89 (2007).</li><li>Nogami, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purkinje-Related+Arrhythmias+Part+I:+Monomorphic+Ventricular+Tachycardias.">Purkinje-Related Arrhythmias Part I: Monomorphic Ventricular Tachycardias.</a> Pacing and Clinical Electrophysiology. 34, 624-650 (2011).</li><li>Clancy, R. M., Kapur, R. P., Molad, Y., Askanase, A. D., Buyon, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunohitologic+Evidence+Supports+Apoptosis,+IgG+Deposition,+and+Novel+Macrophage/Fibroblast+Crosstalk+in+the+Pathologic+Cascade+Leading+to+Congenital+Heart+Block.">Immunohitologic Evidence Supports Apoptosis, IgG Deposition, and Novel Macrophage/Fibroblast Crosstalk in the Pathologic Cascade Leading to Congenital Heart Block.</a> Arthritis and Rheumatism. 50, 173-182 (2004).</li><li>Splawski, 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=CaV1.2+Calcium+Channel+Dysfunction+Causes+a+Multisystem+Disorder+Including+Arrhythmia+and+Autism.">CaV1.2 Calcium Channel Dysfunction Causes a Multisystem Disorder Including Arrhythmia and Autism.</a> Cell. 119, 19-31 (2004).</li><li>Berry, M. N., Friend, D. S., Scheuer, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morphology+and+Metabolism+of+Intact+Muscle+Cells+Isolated+from+Adult+Rat+Heart.">Morphology and Metabolism of Intact Muscle Cells Isolated from Adult Rat Heart.</a> Circulation Research. 26, 679-687 (1970).</li><li>Fang, F., 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=Luteolin+Inhibits+Apoptosis+and+Improves+Cardiomyocyte+Contractile+Function+through+the+PI3K/Akt+pathway+in+Simulated+Ischemia/Reperfusion.">Luteolin Inhibits Apoptosis and Improves Cardiomyocyte Contractile Function through the PI3K/Akt pathway in Simulated Ischemia/Reperfusion.</a> Pharmacology. 88, 149-158 (2011).</li><li>Feng, W., 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=Coordinated+Regulation+of+Murin+Cardiomyocyte+Contractility+by+Nanomolar+(-)-Epigallocatechin-3-Gallate+the+Major+Green+Tea+Catechin.">Coordinated Regulation of Murin Cardiomyocyte Contractility by Nanomolar (-)-Epigallocatechin-3-Gallate the Major Green Tea Catechin.</a> Molecular Pharmacology. 82, 993-1000 (2012).</li><li>Claycomb, W. 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=HL-1+cells:+A+cardiac+muscle+cell+line+that+contracts+and+retains+phenotypic+characteristics+of+the+adult+cardiomyocyte.">HL-1 cells: A cardiac muscle cell line that contracts and retains phenotypic characteristics of the adult cardiomyocyte.</a> Proceedings of the National Academy of Science. 95, 2979-2984 (1998).</li><li>Kaestner, L., 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=Isolation+and+Genetic+Manipulation+of+Adult+Cardiac+Myocytes+for+Confocal+Imaging.">Isolation and Genetic Manipulation of Adult Cardiac Myocytes for Confocal Imaging.</a> J Vis Exp. (31), e1433 (2009).</li><li>Vainio, L., 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=Neronostatin,+a+Novel+Peptide+Encoded+by+Somatostatin+Gene,+Regulates+Cardiac+Contractile+Function+and+Cardiomyocytes+Survival.">Neronostatin, a Novel Peptide Encoded by Somatostatin Gene, Regulates Cardiac Contractile Function and Cardiomyocytes Survival.</a> The Journal of Biological Chemistry. 287, 4572-4580 (2012).</li><li>Park, M., 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=Novel+mechanisms+for+caspase+inhibition+protecting+cardiac+function+wth+chronic+pressure+overload.">Novel mechanisms for caspase inhibition protecting cardiac function wth chronic pressure overload.</a> Basic Research in Cardiology. , 108 (2013).</li><li>Novaes, R. D., 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=Effects+of+Trypanosoma+cruzi+infection+on+myocardial+morphology,+single+cardiomyocyte+contractile+function+and+exercise+tolerance+in+rats.">Effects of Trypanosoma cruzi infection on myocardial morphology, single cardiomyocyte contractile function and exercise tolerance in rats.</a> International Journal of Experimental Pathology. 92, 299-307 (2011).</li><li>Weltman, N. Y., Wang, D., Redetzke, R. A., Gerdes, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Longstanding+Hyperthyroidism+is+Associated+with+Normal+or+Enhanced+Intrinsic+Cardiomyocyte+Function+despite+Decline+in+Global+Cardiac+Function.">Longstanding Hyperthyroidism is Associated with Normal or Enhanced Intrinsic Cardiomyocyte Function despite Decline in Global Cardiac Function.</a> PLoS One. 7, e46655 (2012).</li><li>Papanicolaou, K. N., 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=Preserved+heart+function+and+maintained+response+to+cardiac+stresses+in+a+genetic+model+of+cardiomyocyte-targeted+deficiency+of+cyclooxygenase-2.">Preserved heart function and maintained response to cardiac stresses in a genetic model of cardiomyocyte-targeted deficiency of cyclooxygenase-2.</a> Journal of Molecular and Cellular Cardiology. 49, 196-209 (2010).</li><li>Despa, S., Lingrel, J. B., Bers, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Na+/K+-ATPase+a2-isoform+preferntially+modulates+Ca2++transients+and+sarcoplasmic+reticulum+Ca2++release+in+cardiac+myocytes.">Na+/K+-ATPase a2-isoform preferntially modulates Ca2+ transients and sarcoplasmic reticulum Ca2+ release in cardiac myocytes.</a> Cardiovascular Research. 95, 480-486 (2012).</li><li>Touchberry, C. D., 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=FGF23+is+a+novel+regulator+of+intracellular+calcium+and+cardiac+contractility+in+addition+to+cardiac+hypertophy.">FGF23 is a novel regulator of intracellular calcium and cardiac contractility in addition to cardiac hypertophy.</a> American Journal of Physiology - Endocrinology and Metabolism. , (2013).</li><li>Helmes, M., 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=Titin+Determines+the+Frank-Starling+Relation+in+Early+Diastole.">Titin Determines the Frank-Starling Relation in Early Diastole.</a> The Journal of General Physiology. 121, 97-110 (2003).</li><li>Bell, R. M., Mocanu, M. M., Yellon, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retrograde+heart+perfusion:+The+Langendorff+technique+of+isolated+heart+perfusion.">Retrograde heart perfusion: The Langendorff technique of isolated heart perfusion.</a> Journal of Molecular and Cellular Cardiology. 50, 940-950 (2011).</li><li>Flynn, J. M., Santana, L. F., Melov, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single+Cell+Transcriptional+Profiling+of+Adult+Mouse+Cardiomyocytes.">Single Cell Transcriptional Profiling of Adult Mouse Cardiomyocytes.</a> J Vis Exp. (58), e3302 (2011).</li></ol>

Não temos nada a divulgar.

Isolamento de cardiomiócitos de qualidade requer um certo nível de prática e de otimização. Este protocolo contém passos-chave que podem afetar significativamente o resultado da digestão. Estes devem ser considerados com cuidado na realização e solução de problemas do protocolo. O tempo de remoção do coração de canulação e perfusão deve ser minimizado, de preferência menos do que cinco minutos. Lavar o coração imediatamente em tampão de perfusão gelada após a remoção a partir do rato e dissecan...

Cardiomyocytes provide the contractile force for the heart. Each myocyte contains organized cytoskeletal and contractile elements essential to contraction. The heart not only contains cardiomyocytes but also fibroblasts, connective tissue, and modified myocytes such as Purkinje fibers. Changes in any or all of these cell types can be seen in heart failure, making determination of the ultimate cause of heart dysfunction difficult. Decreased ventricular contractility of a failing heart is preceded by varying degrees of fibrous tissue build-up and hypertrophy and dysfunction of the cardiomyocytes1. Arrhythmias can be caused by dysfunction in the conducting cells2, fibrosis interrupting cardiac conduction3, or changes in the expression of ion channels in cardiomyocytes1,4. Indeed, these problems often co-exist in a complicated fashion.
Isolating and studying cardiomyocytes allows one to examine contractile and electrical dysfunction of individual myocytes in the context of overall heart function. Techniques to isolate individual cardiac myocytes were developed over 40 years ago in an effort to better study physiology of this &#8216;workhorse&#8217; cell of the heart. Isolation techniques have been improved to increase yield and quality of cells, with the vital development of coronary perfusion via cannulation of the aorta, first performed in 19705. This article describes cardiomyocyte isolation followed by measurement of contractility and calcium transients using ratiometric fluorescence and cell dimensioning data acquisition software. In both genetic and environmental models of heart disease, utilizing this protocol provides key information about cell contractility, sarcomeric contractility and relaxation, calcium transients, and cytoskeletal disruption. This system is often used to test the effect of drugs on isolated cardiomyocytes6,7. We employ the system to compare contractility and calcium transients of cardiomyocytes between wild type mice and mice with a mutation leading to dilated cardiomyopathy.
Studying individual cardiac myocytes has numerous advantages over other commonly used methods to study cardiac anatomy and physiology. Echocardiography and electrocardiography provide information about the contractile function and electrical conduction of the heart overall. Neither of these methods explains the cause or nature of the dysfunction below the level of the whole organ. Measuring contractility of individual cardiomyocytes using edge-detection and sarcomere length algorithms can demonstrate that changes within the contractile cell of the heart are present within global heart dysfunction. Measuring calcium transients demonstrates the influence of changes in ion flux at a cellular level to contractile dysfunction or arrhythmias.
In addition to complementing whole organ studies, this protocol provides cells easily stained for sub-cellular components. It is possible to see cytoskeletal changes by staining tissue sections of the whole heart; however, one is only able to visualize a cross section of cells. A whole cardiomyocyte is thicker than the typical tissue section, and given the arrangement and length of the cardiomyocytes, it is difficult to see whole cells in a single section. Isolated cardiomyocytes can be fixed immediately and stained for a variety of cytoskeletal elements and ion channels. Confocal images can be compiled into full thickness z-stacks of the cell. Additionally, staining isolated cardiac myocytes allows for staining of components that are impossible to visualize in sections, such as the membrane invaginations known as t-tubules.
Cultured cell lines of cardiac myocytes do exist, some of which have similar transcriptional profiles and phenotypic features to cardiac myocytes. Some, such as the HL-1 cell line, even retain some sarcomeric organization and rudimentary contractile ability8. Despite these qualities, cultured cells lack the &#8220;box car&#8221; shape and t-tubule structure of cardiomyocytes and have less sarcomeric organization. These components are essential to the function of cardiomyocytes in vivo. In addition, using cultured cells allows genetic manipulation but not in vivo physiologic manipulation. Isolated cardiomyocytes retain their cellular organization long enough to study but are still easily imaged and even transduced9. 
Isolated cardiomyocytes are extremely versatile, providing a substrate to identically analyze cells from varied experimental conditions. Isolation and physiological analysis of myocytes have been used by countless labs for a variety of experiments including studying the effect of drugs6,7 or small molecules10, environmental stressors11, infection12, illness13, or genetic mutation14,15 on contractility and/or calcium transients and studying the regulation of contractility and calcium release within a cardiomyocyte15-17. With the application of any of these stressors, changes in heart function could be due to any combination of changes in the cardiomyocytes themselves and changes in the surrounding environment of the heart, such as scarring, changes in conductivity, or changes to the extracellular matrix. This is an ideal protocol for answering research questions regarding individual myocyte structure and function in the context of heart failure from any cause.
Although it has countless advantages over other techniques, physiological analysis of isolated cardiomyocytes is not ideal for every research question. Isolation is a terminal procedure, thus cardiomyocytes can only be assessed at one time in the mouse&#8217;s life. This can be partially overcome using cohorts and sacrificing individual mice along the course of illness development or by monitoring the mouse to determine whether it has clinically significant heart failure before isolation. Although this protocol can determine whether cardiomyocyte dysfunction has occurred, one cannot draw the conclusion that this dysfunction is the root cause of heart failure without additional experimental information. It is possible that cardiomyocyte dysfunction itself is secondary to other changes in the heart. Despite these challenges, studying cardiomyocytes offers valuable information in determining the nature of dysfunction in the heart, especially when combined with other experiments. 
The following protocol is adapted from one provided by Dr. Chee Lim, Vanderbilt University. Although contractility and calcium flux data are highly reproducible and useful in comparing hearts with genetic or environmental manipulation, isolation itself remains a technique dependent protocol, requiring optimization. Minimizing the time between removing the heart from the mouse and perfusing the heart via aortic cannulation is essential for a quality digestion. In addition, digestion time and enzyme concentration can be optimized for the highest quality myocytes. Steps likely requiring optimization, along with suggestions for optimization, are noted below.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr height="22">
			<td height="22" style="height:22px;width:253px;">NaCl</td>
			<td style="width:221px;">RPI</td>
			<td style="width:159px;">S23020</td>
			<td style="width:88px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:253px;">KCl</td>
			<td style="width:221px;">Sigma</td>
			<td style="width:159px;">P-3911</td>
			<td></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:253px;">MgCl2</td>
			<td style="width:221px;">Sigma</td>
			<td style="width:159px;">M-8266</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:253px;">HEPES</td>
			<td style="width:221px;">EM Science</td>
			<td style="width:159px;">S320</td>
			<td></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:253px;">NaH2PO4</td>
			<td style="width:221px;">Sigma</td>
			<td style="width:159px;">S5011</td>
			<td></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:253px;">CaCl2 &#376; 2H2O</td>
			<td style="width:221px;">Fisher</td>
			<td style="width:159px;">C79</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:253px;">D-(+)-Glucose</td>
			<td style="width:221px;">Sigma</td>
			<td style="width:159px;">G7528</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:253px;">2,3-Butanedione-monoxime (BDM)</td>
			<td style="width:221px;">Sigma</td>
			<td style="width:159px;">B-0753</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:253px;">Taurine</td>
			<td style="width:221px;">Sigma</td>
			<td style="width:159px;">T-0625</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:253px;">Bovine Serum Albumin (BSA)</td>
			<td style="width:221px;">Sigma</td>
			<td style="width:159px;">A-7030</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:253px;">Collagenase B</td>
			<td style="width:221px;">Roche Diagnostics</td>
			<td style="width:159px;">1-088-823</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:253px;">Collagenase D</td>
			<td style="width:221px;">Roche Diagnostics</td>
			<td style="width:159px;">1-088-882</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:253px;">Protease XIV</td>
			<td style="width:221px;">Sigma</td>
			<td style="width:159px;">P-5147</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:253px;">Heparin</td>
			<td style="width:221px;">APP Pharmaceuticals, LLC</td>
			<td style="width:159px;">401586D</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:253px;">Isofluorane</td>
			<td style="width:221px;">Butler Schein</td>
			<td style="width:159px;">11695-6776-2</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:253px;">Fura-2 AM</td>
			<td style="width:221px;">Teflabs</td>
			<td style="width:159px;">103</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:253px;">DMSO &#8211; anhydrous</td>
			<td style="width:221px;">Sigma</td>
			<td style="width:159px;">276855</td>
			<td></td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:253px;">IonOptix cell pacing and fluorescent analysis system</td>
			<td style="width:221px;">IonOptix</td>
			<td style="width:159px;"></td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:253px;">250 um nylon mesh filter</td>
			<td style="width:221px;">Sefar America</td>
			<td style="width:159px;">Lab Pak 03-250/50</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:253px;">23G leur-stub adaptor</td>
			<td style="width:221px;">Becton Dickinson</td>
			<td style="width:159px;">1482619E</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:253px;">PE-50 tubing</td>
			<td style="width:221px;">Becton Dickinson</td>
			<td style="width:159px;">427410</td>
			<td></td>
		</tr>
	</tbody>
</table>

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.

Uma vez que a contratilidade e traçados transitórios são coletados (Figura 2), os dados são facilmente analisadas com o software apropriado. Toda a rastreio, ou respectivas porções, pode ser calculada a média (Figura 3). Contractilidade pode ser analisado de uma variedade de maneiras. Para a função sistólica, pode-se avaliar a magnitude da contração com fração de encurtamento, ou a velocidade de contração com o tempo para atingir o encurtamento, e velocidade de contraç?...

Watch this Scientific Journal Video about Isolation and Physiological Analysis of Mouse Cardiomyocytes at JoVE.com

Isolation and Physiological Analysis of Mouse Cardiomyocytes

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.

Isolamento e Fisiológica Análise de rato Cardiomyocytes

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

isolation-and-physiological-analysis-of-mouse-cardiomyocytes

Research

JoVE Journal

Biology

22.9K visualizações.  Vanderbilt University.  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. 

Vídeo: Isolation and Physiological Analysis of Mouse Cardiomyocytes

Dissection of Hippocampal Dentate Gyrus from Adult Mouse

The hippocampus is one of the most widely studied areas in the brain because of its important functional role in memory processing and learning, its remarkable neuronal cell plasticity, and its involvement in epilepsy, neurodegenerative diseases, and psychiatric disorders. The hippocampus is composed of distinct regions; the dentate gyrus, which comprises mainly granule neurons, and Ammon's horn, which comprises mainly pyramidal neurons, and the two regions are connected by both anatomic and functional circuits. Many different mRNAs and proteins are selectively expressed in the dentate gyrus, and the dentate gyrus is a site of adult neurogenesis; that is, new neurons are continually generated in the adult dentate gyrus. To investigate mRNA and protein expression specific to the dentate gyrus, laser capture microdissection is often used. This method has some limitations, however, such as the need for special apparatuses and complicated handling procedures. In this video-recorded protocol, we demonstrate a dissection technique for removing the dentate gyrus from adult mouse under a stereomicroscope. Dentate gyrus samples prepared using this technique are suitable for any assay, including transcriptomic, proteomic, and cell biology analyses. We confirmed that the dissected tissue is dentate gyrus by conducting real-time PCR of dentate gyrus-specific genes, tryptophan 2,3-dioxygenase (TDO2) and desmoplakin (Dsp), and Ammon's horn enriched genes, Meis-related gene 1b (Mrg1b) and TYRO3 protein tyrosine kinase 3 (Tyro3). The mRNA expressions of TDO2 and Dsp in the dentate gyrus samples were detected at obviously higher levels, whereas Mrg1b and Tyro3 were lower levels, than those in the Ammon's horn samples. To demonstrate the advantage of this method, we performed DNA microarray analysis using samples of whole hippocampus and dentate gyrus. The mRNA expression of TDO2 and Dsp, which are expressed selectively in the dentate gyrus, in the whole hippocampus of alpha-CaMKII+/- mice, exhibited 0.037 and 0.10-fold changes compared to that of wild-type mice, respectively. In the isolated dentate gyrus, however, these expressions exhibited 0.011 and 0.021-fold changes compared to that of wild-type mice, demonstrating that gene expression changes in dentate gyrus can be detected with greater sensitivity. Taken together, this convenient and accurate dissection technique can be reliably used for studies focused on the dentate gyrus.

A dissection technique for removal of the dentate gyrus from adult mouse under a stereomicroscope was demonstrated in this video-recorded protocol.

Dissecção do giro denteado do hipocampo de rato adulto

The hippocampus is one of the most widely studied areas in the brain because of its important functional role in memory processing and learning, its ...

Biologia

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Human cancer and response to therapy is better represented in orthotopic animal models. This paper describes the development of an orthotopic mouse model of ovarian cancer, treatment of cancer via oral delivery of drugs, and monitoring of tumor cell behavior in response to drug treatment in real time using in vivo imaging system. In this orthotopic model, ovarian tumor cells expressing luciferase are applied topically by injecting them directly into the mouse bursa where each ovary is enclosed. Upon injection of D-luciferin, a substrate of firefly luciferase, luciferase-expressing cells generate bioluminescence signals. This signal is detected by the in vivo imaging system and allows for a non-invasive means of monitoring tumor growth, distribution, and regression in individual animals. Drug administration via oral gavage allows for a maximum dosing volume of 10 mL/kg body weight to be delivered directly to the stomach and closely resembles delivery of drugs in clinical treatments. Therefore, techniques described here, development of an orthotopic mouse model of ovarian cancer, oral delivery of drugs, and in vivo imaging, are useful for better understanding of human ovarian cancer and treatment and will improve targeting this disease.

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Orthotopic animal models of ovarian cancer replicate better human disease and therefore enhance our understanding of cancer progression and tumor response to therapy. A mouse model receives an intrabursal injection of luciferase-expressing ovarian tumor cells. Treatment is administered via oral gavage. Tumor growth is monitored by in vivo imaging system.

In vivo de imagens e tratamentos terapêuticos em um modelo de camundongo ortotópico de câncer de ovário

Human cancer and response to therapy is better represented in orthotopic animal models.  This paper describes the development of an orthotopic mouse model ...

Single Cell Transcriptional Profiling of Adult Mouse Cardiomyocytes

While numerous studies have examined gene expression changes from homogenates of heart tissue, this prevents studying the inherent stochastic variation between cells within a tissue. Isolation of pure cardiomyocyte populations through a collagenase perfusion of mouse hearts facilitates the generation of single cell microarrays for whole transcriptome gene expression, or qPCR of specific targets using nanofluidic arrays. We describe here a procedure to examine single cell gene expression profiles of cardiomyocytes isolated from the heart. This paradigm allows for the evaluation of metrics of interest which are not reliant on the mean (for example variance between cells within a tissue) which is not possible when using conventional whole tissue workflows for the evaluation of gene expression (Figure 1). We have achieved robust amplification of the single cell transcriptome yielding micrograms of double stranded cDNA that facilitates the use of microarrays on individual cells. In the procedure we describe the use of NimbleGen arrays which were selected for their ease of use and ability to customize their design. Alternatively, a reverse transcriptase - specific target amplification (RT-STA) reaction, allows for qPCR of hundreds of targets by nanofluidic PCR. Using either of these approaches, it is possible to examine the variability of expression between cells, as well as examining expression profiles of rare cell types from within a tissue. Overall, the single cell gene expression approach allows for the generation of data that can potentially identify idiosyncratic expression profiles that are typically averaged out when examining expression of millions of cells from typical homogenates generated from whole tissues.

Single cell expression profiling allows the detailed gene expression analysis of individual cells. We describe methods for the isolation of cardiomyocytes, and preparing the resulting lysates for either whole transcriptome microarray or qPCR of specific targets.

Profiling única célula transcricional dos cardiomiócitos de rato adulto

While numerous studies have examined gene expression changes from homogenates of heart tissue, this prevents studying the inherent stochastic variation ...

Isolation and Kv Channel Recordings in Murine Atrial and Ventricular Cardiomyocytes

KCNE genes encode for a small family of Kv channel ancillary subunits that form heteromeric complexes with Kv channel alpha subunits to modify their functional properties. Mutations in KCNE genes have been found in patients with cardiac arrhythmias such as the long QT syndrome and/or atrial fibrillation. However, the precise molecular pathophysiology that leads to these diseases remains elusive. In previous studies the electrophysiological properties of the disease causing mutations in these genes have mostly been studied in heterologous expression systems and we cannot be sure if the reported effects can directly be translated into native cardiomyocytes. In our laboratory we therefore use a different approach. We directly study the effects of KCNE gene deletion in isolated cardiomyocytes from knockout mice by cellular electrophysiology - a unique technique that we describe in this issue of the Journal of Visualized Experiments. The hearts from genetically engineered KCNE mice are rapidly excised and mounted onto a Langendorff apparatus by aortic cannulation. Free Ca2+ in the myocardium is bound by EGTA, and dissociation of cardiac myocytes is then achieved by retrograde perfusion of the coronary arteries with a specialized low Ca2+ buffer containing collagenase. Atria, free right ventricular wall and the left ventricle can then be separated by microsurgical techniques. Calcium is then slowly added back to isolated cardiomyocytes in a multiple step comprising washing procedure. Atrial and ventricular cardiomyocytes of healthy appearance with no spontaneous contractions are then immediately subjected to electrophysiological analyses by patch clamp technique or other biochemical analyses within the first 6 hours following isolation.

Kv channel dysfunction is associated with cardiac arrhythmias. In order to study the molecular mechanisms that lead to such arrhythmias we utilize a systematic protocol for isolation of atrial and ventricular cardiomyocytes from Kv channel ancillary subunit knockout mice. Isolated cardiomyocytes can then immediately be used for cellular electrophysiological studies, biochemical or immunofluorescence (IF) assays.

Isolamento e gravações de canais Kv em Murino cardiomiócitos atriais e ventriculares

KCNE genes encode for a small family of Kv channel ancillary subunits that form heteromeric complexes with Kv channel alpha subunits to modify their ...

Isolation and Culture of Neonatal Mouse Cardiomyocytes

Cultured neonatal cardiomyocytes have long been used to study myofibrillogenesis and myofibrillar functions. Cultured cardiomyocytes allow for easy investigation and manipulation of biochemical pathways, and their effect on the biomechanical properties of spontaneously beating cardiomyocytes.	
The following 2-day protocol describes the isolation and culture of neonatal mouse cardiomyocytes. We show how to easily dissect hearts from neonates, dissociate the cardiac tissue and enrich cardiomyocytes from the cardiac cell-population. We discuss the usage of different enzyme mixes for cell-dissociation, and their effects on cell-viability. The isolated cardiomyocytes can be subsequently used for a variety of morphological, electrophysiological, biochemical, cell-biological or biomechanical assays. We optimized the protocol for robustness and reproducibility, by using only commercially available solutions and enzyme mixes that show little lot-to-lot variability. We also address common problems associated with the isolation and culture of cardiomyocytes, and offer a variety of options for the optimization of isolation and culture conditions.

Primary mouse cardiomyocyte cultures are one of the pivotal tools for the investigation of myofibrillar organization and function. The following protocol describes the isolation and culture of primary cardiomyocytes from neonatal mouse hearts. The resulting cardiomyocyte cultures may be subsequently used for a variety of biomechanical, biochemical and cell-biological assays.

Isolamento e Cultura de Neonatais rato Cardiomyocytes

Cultured neonatal cardiomyocytes have long been used to study  myofibrillogenesis and myofibrillar functions. Cultured cardiomyocytes allow  for easy ...

Isolation and Culture of Adult Mouse Cardiomyocytes for Cell Signaling and in vitro Cardiac Hypertrophy

Technological advances have made genetically modified mice, including transgenic and gene knockout mice, an essential tool in many research fields. Adult cardiomyocytes are widely accepted as a good model for cardiac cellular physiology and pathophysiology, as well as for pharmaceutical intervention. Genetically modified mice preclude the need for complicated cardiomyocyte infection processes to generate the desired genotype, which are inefficient due to cardiomyocytes&#8217; terminal differentiation. Isolation and culture of high quantity and quality functional cardiomyocytes will dramatically benefit cardiovascular research and provide an important tool for cell signaling transduction research and drug development. Here, we describe a well-established method for isolation of adult mouse cardiomyocytes that can be implemented with little training. The mouse heart is excised and cannulated to an isolated heart system, then perfused with a calcium-free and high potassium buffer followed by type II collagenase digestion in Langendorff retrograde perfusion mode. This protocol yields a consistent result for the collection of functional adult mouse cardiomyocytes from a variety of genetically modified mice.

Isolation and Culture of Adult Mouse Cardiomyocytes for Cell Signaling and in vitro Cardiac Hypertrophy

We describe a reliable method for isolation of adult mouse cardiomyocytes. This protocol yields a consistent result for the culture of functional adult cardiomyocytes from a variety of genetically modified mice.

Isolamento e Cultura de rato adulto Cardiomyocytes de sinalização celular e<em&gt; In vitro</em&gt; A hipertrofia cardíaca

Technological advances have made genetically modified mice, including transgenic and gene knockout mice, an essential tool in many research fields. Adult ...

Isolation and Functional Analysis of Mitochondria from Cultured Cells and Mouse Tissue

Comparison between two or more distinct groups, such as healthy vs. disease, is necessary to determine cellular status. Mitochondria are at the nexus of cell heath due to their role in both cell metabolism and energy production as well as control of apoptosis. Therefore, direct evaluation of isolated mitochondria and mitochondrial perturbation offers the ability to determine if organelle-specific (dys)function is occurring. The methods described in this protocol include isolation of intact, functional mitochondria from HEK cultured cells and mouse liver and spinal cord, but can be easily adapted for use with other cultured cells or animal tissues. Mitochondrial function assessed by TMRE and the use of common mitochondrial uncouplers and inhibitors in conjunction with a fluorescent plate reader allow this protocol not only to be versatile and accessible to most research laboratories, but also offers high throughput.

Comparison of mitochondrial membrane potential between samples yields valuable information about cellular status. Detailed steps for isolating mitochondria and assessing response to inhibitors and uncouplers using fluorescence are described. The method and utility of this protocol are illustrated by use of a cell culture and animal model of cellular stress.

Isolamento e Análise Funcional de mitocôndrias de células cultivadas e mouse Tissue

Comparison between two or more distinct groups, such as healthy vs. disease, is necessary to determine cellular status. Mitochondria are at the nexus of ...

Isolation, Culture and Transduction of Adult Mouse Cardiomyocytes

Cultured cardiomyocytes can be used to study cardiomyocyte biology using techniques that are complementary to in vivo systems. For example, the purity and accessibility of in vitro culture enables fine control over biochemical analyses, live imaging, and electrophysiology. Long-term culture of cardiomyocytes offers access to additional experimental approaches that cannot be completed in short term cultures. For example, the in vitro investigation of dedifferentiation, cell cycle re-entry, and cell division has thus far largely been restricted to rat cardiomyocytes, which appear to be more robust in long-term culture. However, the availability of a rich toolset of transgenic mouse lines and well-developed disease models make mouse systems attractive for cardiac research. Although several reports exist of adult mouse cardiomyocyte isolation, few studies demonstrate their long-term culture. Presented here, is a step-by-step method for the isolation and long-term culture of adult mouse cardiomyocytes. First, retrograde Langendorff perfusion is used to efficiently digest the heart with proteases, followed by gravity sedimentation purification. After a period of dedifferentiation following isolation, the cells gradually attach to the culture and can be cultured for weeks. Adenovirus cell lysate is used to efficiently transduce the isolated cardiomyocytes. These methods provide a simple, yet powerful model system to study cardiac biology.

This protocol describes a step-by-step method for the reproducible isolation and long-term culture of adult mouse cardiomyocytes with high yield, purity, and viability.

Isolamento, cultura e Transdução de rato adulto Cardiomyocytes

Cultured cardiomyocytes can be used to study cardiomyocyte biology using techniques that are complementary to in vivo systems. For example, the purity and ...

Simultaneous Isolation of High Quality Cardiomyocytes, Endothelial Cells, and Fibroblasts from an Adult Rat Heart

The rat is an important animal model used in cardiovascular research, and rat cardiac cells are used routinely for in vitro analysis of the molecular mechanisms of cardiovascular disease progression such as cardiac hypertrophy, fibrosis, and atherosclerosis. Although several attempts with variable success have been made to develop immortalized cell lines from the cardiovascular system to understand these cellular mechanisms, primary cells offer a more natural and close to in vivo environment for such studies. Therefore, different laboratories working on a particular cell type have developed protocols to isolate individual types of rat cardiac cells of interest. A protocol that allows the isolation of more than one cell type, however, is missing. Here an optimized protocol is described that allows the isolation of high-quality major cardiac cell types (cardiomyocytes, endothelial cells, and fibroblasts) from a single preparation and enables their use for cellular analyses. This permits the most efficient use of available resources, which may save time and reduce research costs.

Several protocols have been developed and described for the isolation of different cardiac cell types from a rat heart. Here, an optimized protocol is described that allows the isolation of high-quality major cardiac cell types (cardiomyocytes, endothelial cells, and fibroblasts) from a single preparation, reducing the experimental costs.

Isolamento Simultâneo de Cardiomiócitos de Alta Qualidade, Células Endoteliais e Fibroblastos de um Coração de Rato Adulto

The rat is an important animal model used in cardiovascular research, and rat cardiac cells are used routinely for in vitro analysis of the molecular ...

Isolation of Cardiomyocytes from Fixed Hearts for Immunocytochemistry and Ploidy Analysis

The adult mammalian heart is composed of various cell types including cardiomyocytes, endothelial cells and fibroblasts. Since it is difficult to reliably identify nuclei of cardiomyocytes on histological sections, many groups rely on isolating viable cardiomyocytes prior to fixation to perform immunostaining. However, these live cardiomyocyte isolation techniques require optimization to maximize the yield, viability and quality of the samples, with inherent fluctuations from sample to sample despite maximum optimization. Here, we report a reproducible protocol, involving fixation prior to enzymatic digestion of the heart, which leads to maximum yield while preserving the in vivo morphology of individual cardiomyocytes. We further developed an automated analysis platform to determine the number of nuclei and DNA content per nucleus for individual cardiomyocytes. After exposing the chest cavity, the heart was arrested in diastole by perfusion with 60 mM KCl in PBS. Next, the heart was fixed in 4% paraformaldehyde (PFA) solution, and then digested with 60 mg/mL collagenase solution. After digestions, cells were singularized by trituration, and the cardiomyocyte fraction was enriched via differential centrifugation. Isolated cardiomyocytes were stained for Troponin T and &#945;-actinin to assess purity of the obtained population. Furthermore, we developed an image analysis platform to determine cardiomyocyte nucleation and ploidy status following DAPI staining. Image based ploidy assessments led to consistent and reproducible results. Thus, with this protocol, it is possible to preserve native morphology of individual cardiomyocytes to allow immunocytochemistry and DNA content analysis while achieving maximum yield.

The goal of this work is to develop a method to reproducibly isolate cardiomyocytes from the adult heart and measure DNA content and nucleation.

Isolamento de Cardiomiócitos de Corações Fixos para Imunocitoquímica e Análise ploidy

The adult mammalian heart is composed of various cell types including cardiomyocytes, endothelial cells and fibroblasts. Since it is difficult to reliably ...