Este trabalho foi financiado por uma concessão do National Eye Institute (R01 EY12998) para FH Andrade.

1. Preparação de Buffers <ol><li> Ligue 5804R centrífuga e definir a 4 ° C. Ligue Isotemp banho de água 3006D e definida para 37 ° C. </li><li> Preparar as soluções seguintes antes de isolamento muscular: <ul><li> PBS: Dissolver tampão fosfato salino (PBS) comprimidos em água destilada (5 comprimidos / litro). Misture bem. </li><li> PBS acrescido de 10 mM EDTA: Para preparar uma solução de 100 ml, adicionar 2 ml de 500 mM EDTA a 98 ml de PBS. </li><li> Buffer de mitocôndrias 8X: 10,28 g de sacarose para uma concentração final de 0,6 M, 400 mg de ácido graxo livre-albumina sérica bovina (BSA) para uma concentração final de 0,8%, 2,08 g de HEPES para uma concentração final de 160 mM, pH para 7,4 e QS de 50 ml com água destilada. </li><li> Tampão de isolamento 1 (IB1): Adicione 200 mL de 500 mM EDTA para uma concentração final de 10 mM, 0,392 g de D-manitol para uma concentração final de 215 mM, 1,25 ml de 8X mitocôndrias tampão pH, para 7,4 e QS a 10 ml com água destilada. </li><li> Tampão de isolamento 2 (IB2): Adicionar 60 mL de 500 mM EGTA para uma concentração final de 3 mM, 0,392 g de D-manitol para uma concentração final de 215 mM, 1,25 ml de 8X mitocôndrias tampão pH, para 7,4 e QS a 10 ml com água destilada. </li><li> Tampão Experimental (EB): Adicionar 100 l de 500 mM MgCl 2 para uma concentração final de 5 mM, 0,392 g de D-manitol para uma concentração final de 215 mm, 25 mL de 2,5 mM KH 2 PO 4 para uma concentração final de 6,25 mM, 2 l de 100 mM EGTA para uma concentração final de 20 mM, 1,25 ml de tampão mitocondrial, pH de 7,4 e QS a 10 ml com água destilada. </li></ul></li></ol> 2. Isolamento muscular <ol><li> Em um balde de gelo, colocar três copos de 10 ml, moedores Potter-Elvehjem tecido e todos os outros instrumentos necessários / supplies no gelo. Tudo deve ficar gelada durante todo o experimento. </li><li> Lugar IB1 e IB2 em balde de gelo e EB em banho de água quente quando terminar. </li><li> Nos três copos 10 ml, as seguintes soluções devem ser adicionadas: <ul><li> Copo 1: 10 ml de PBS </li><li> Copo 2: 10 ml de PBS / EDTA </li><li> Copo de 3: 3 ml de IB1 </li></ul></li><li> Matar um rato humanamente aprovado pelo seu Animal Care locais Institucional e Comitê de uso. </li><li> Isolar rapidamente 250-500 mg de músculo esquelético, lavar em uma taça, e transferir para Beaker 2. </li></ol> 3. Homogeneização / isolamento mitocondrial <ol><li> Transferência de músculo para copo de 3 e finamente picada do músculo com uma tesoura. </li><li> Transferir a solução para o homogeneizador Potter-Elvehjem. Homogeneizar o músculo usando um pilão motorizado (uma imprensa de broca irá fazer o trabalho) 10 vezes mantendo o tubo no gelo em todos os momentos. </li><li> Transferência de homogenato de pré-refrigerados tubos de microcentrífuga 2 ml e centrifugar a 700 g por 10 minutos a 4 ° C. </li><li> Transfira o sobrenadante para um tubo de microcentrífuga novo pré-refrigerados. Descartar pellet. </li><li> Centrifugar o sobrenadante do 10.500 g por 10 minutos a 4 ° C. </li><li> Transfira o sobrenadante para um tubo de microcentrífuga novo pré-refrigerados e SN1 etiqueta (número sobrenadante 1) e tipo de músculo. </li><li> Re-suspender pellet em 500 mL de IB2. </li><li> Centrifugar a 10.500 g por 10 minutos a 4 ° C. </li><li> Transfira o sobrenadante para um tubo de microcentrífuga novo pré-refrigerados e SN2 etiqueta (número sobrenadante 2) e tipo de músculo. </li><li> Suspender finais mitocondrial pellet em 100 ml de IB2. </li><li> Re spin-finais suspensão mitocondrial em minifuge por alguns segundos. Se houver um pellet, transferir o sobrenadante para um novo tubo de microcentrífuga pré-refrigerados e descartar o pellet. </li><li> Determinar a concentração de proteína utilizando o ensaio de Bradford 8. </li></ol> 4. Calibração do eletrodo NOTA: calibração do eletrodo Completa durante o isolamento mitocondrial. <ol><li> Adicione 100 ml de água destilada para 250 ml. Mexa vigorosamente por 20 minutos para equilibrar a água com gás atmosférico. </li><li> Adicione algumas gotas de 50% KCl no eletrodo Oxygraph. </li><li> Coloque um pequeno pedaço de papel de Blue Rizla rolando em cima do eletrodo. </li><li> Coloque um pedaço de membrana PTFE em cima do papel para enrolar. </li><li> Aplicar o anel interno utilizando o aplicador de anel e, em seguida, coloque o anel externo na ranhura do eletrodo. </li><li> Conectar eletrodos e montar o resto do equipamento: base maior anel de plástico, câmara mitocondrial, e mangueiras de água. </li><li> Ligar caixas de Oxygraph e começar software Oxygraph. </li><li> Adicione a água equilibrada para a câmara mitocondrial. </li><li> Adicionar agitar bar e ligue a uma velocidade de 60. </li><li> Começar uma nova experiência. </li><li> Clique em calibrar e, em seguida, a calibração de fase líquida para Box 1. Mudança de temperatura para 37 ° C e clique em &quot;OK&quot; duas vezes. </li><li> Quando &quot;Substituir&quot; muda para &quot;OK&quot; clique nele e abrir o tanque de gás nitrogênio. </li><li> Ponta lugar conectadopara o tanque de nitrogênio na câmara e estabelecer oxigênio zero. Clique em &quot;OK&quot; quando se muda de &quot;Ignorar&quot;. </li><li> Aspirar água e adicionar 500 mL de tampão EB às câmaras mitocondrial. </li><li> Vedação de câmara com êmbolo. </li><li> Se estiver usando várias caixas, repita os passos 11-15 para calibração de Caixa 2. </li></ol> 5. A respiração mitocondrial <ol><li> Iniciar uma nova experiência; deixá-lo correr por cerca de 1 minuto para estabilizar sinal. </li><li> Adicionar o volume necessário da suspensão mitocondrial (passo 3.11) para 150 mg em cada câmara, o evento marca, e deixá-lo correr por 1 minuto. </li><li> Adicionar 10 ml de morno 250 mM/125 mM glutamato / malato para uma concentração final de 5 mM mM/2.5. Marca e deixar correr por 1 minuto. Esta é definida como estado 2. </li><li> Adicionar 7,5 mL de 10 mM ADP para uma concentração final de 150 mM, marca, e deixar correr por 30 segundos. Isto é definido como Estado 3. </li><li> Adicionar outro mL 7,5 mM ADP, de 10, marca, e deixar correr para 1,5 minutos. </li><li> Adicionar 0,5 mL de oligomicina mM frio 10 para uma concentração final de 1 mM, marca, e deixar correr por 3 minutos. Isto é definido como Estado 4. </li><li> Adicionar 1 ml de frio 0,1 mM FCCP para uma concentração final de 0,2 mM, marca, e deixar correr por 3 minutos. Isto é definido como Estado 5. </li><li> Quando terminar, final experimentar e salvar. </li><li> Adquirir taxas de respiração usando software Oxygraph. </li><li> Digite fator de normalização: se a adição de 150 mg de proteína mitocondrial, o fator de normalização será 0,15. </li><li> Calcular as taxas de respiração normalizada para os estados de respiração diferente. </li><li> Calcular a Razão de Controle Respiratório (RCR) dividindo-se 3 por Estado Estado 4. </li></ol> 6. Resultados representativos: <img src="/files/ftp_upload/2452/2452fig1.jpg" alt="Figura 1" /> Figura 1. Mostra um representante rastreamento do consumo de oxigênio pelo músculo esquelético mitocôndrias. Após o sinal de eletrodo é estabilizado, a amostra mitocôndria é adicionado à câmara Oxygraph. Estado respiração 2 começa com adição de glutamato e malato. Adição de ADP aumenta o consumo de oxigênio, que define a respiração estado 3. ATP sintase é bloqueada pela adição de oligomicina para obter a respiração estado 4. Finalmente, FCCP é adicionado ao desacoplar respiração mitocondrial (estado 5). Tabela 1 mostra as taxas de consumo de oxigênio representante para os estados 2, 3, 4 e 5. A relação de controle respiratório (RCR) é calculado para cada experimento. RCR ≥ 4 é considerado como evidência de uma preparação de mitocôndrias viáveis. <table border="1"><tbody><tr><td> Estados </td><td> Preços normalizado </td></tr><tr><td> Estado 2 </td><td> 34,74 </td></tr><tr><td> Estado 3 </td><td> 153,40 </td></tr><tr><td> Estado 4 </td><td> 16,49 </td></tr><tr><td> Estado 5 </td><td> 143,70 </td></tr><tr><td> RCR </td><td> 9,30 </td></tr></tbody></table> Tabela 1. Taxas de respiração mitocondrial. Taxas de consumo Representativeoxygen do músculo esquelético mitocôndrias. Os valores são normalizados para a quantidade de mitocôndrias adicionado à câmara. A relação de controle respiratório (RCR) é determinado pela divisão do estado 3 por estado 4. Um RCR ≥ 4 representa uma preparação viável mitocôndrias.

<ol>
	<li>Frezza, C., Cipolat, S., Scorrano, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organelle+isolation:+functional+mitochondria+from+mouse+liver,+muscle+and+cultured+fibroblasts.">Organelle isolation: functional mitochondria from mouse liver, muscle and cultured fibroblasts.</a> Nat Protoc. 2, 287-295 (2007).</li><li>Duchen, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Roles+of+mitochondria+in+health+and+disease.">Roles of mitochondria in health and disease.</a> Diabetes. 53, S96-S102 (2004).</li><li>Johannsen, D. L., Ravussin, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+mitochondria+in+health+and+disease.">The role of mitochondria in health and disease.</a> Curr Opin Pharmacol. , (2009).</li><li>Pallotti, F., Lenaz, G. <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+subfractionation+of+mitochondria+from+animal+cells+and+tissue+culture+lines.">Isolation and subfractionation of mitochondria from animal cells and tissue culture lines.</a> Methods Cell Biol. 80, 3-44 (2007).</li><li>Pallotti, F., Lenaz, G. <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+subfractionation+of+mitochondria+from+animal+cells+and+tissue+culture+lines.">Isolation and subfractionation of mitochondria from animal cells and tissue culture lines.</a> Methods Cell Biol. 65, 1-35 (2001).</li><li>Gamboa, J. L., Andrade, F. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitochondrial+content+and+distribution+changes+specific+to+mouse+diaphragm+after+chronic+normobaric+hypoxia.">Mitochondrial content and distribution changes specific to mouse diaphragm after chronic normobaric hypoxia.</a> Am J Physiol Regul Integr Comp Physiol. , (2009).</li><li>Patel, S. P., Gamboa, J. L., McMullen, C. A., Rabchevsky, A., Andrade, F. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lower+respiratory+capacity+in+extraocular+muscle+mitochondria:+evidence+for+intrinsic+differences+in+mitochondrial+composition+and+function.">Lower respiratory capacity in extraocular muscle mitochondria: evidence for intrinsic differences in mitochondrial composition and function.</a> Invest Ophthalmol Vis Sci. 50, 180-186 (2009).</li><li>Bradford, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+rapid+and+sensitive+method+for+the+quantitation+of+microgram+quantities+of+protein+utilizing+the+principle+of+protein-dye+binding.">A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding.</a> Anal Biochem. 72, 248-254 (1976).</li></ol>

Não há conflitos de interesse declarados.

Nós apresentamos um protocolo para isolar mitocôndrias viáveis ​​do músculo esquelético. Se o rendimento é um problema, o protocolo pode ser modificada, incubando o músculo isolado em 5 ml de tripsina EDTA/0.01 PBS/10mM% por 30 minutos em gelo. Para assegurar a digestão muscular completo com tripsina, o músculo precisa ser totalmente picada. Após a incubação de 30 minutos, a solução de tripsina PBS/10mM EDTA/0.01% deve ser completamente substituído com 3 ml de isolamento tampão 1 (IB1). Além disso, ...

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">	
		
		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>95% CO2 / 5% O2 mix</td>
<td>&nbsp;</td>
<td>Local gas company</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Adenosine 5&#x2032;-diphosphate sodium salt</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>A2754</td>
<td>&nbsp;</td>
<tr>
<td>Blue Rizla Paper</td>
<td>&nbsp;</td>
<td>Hansatech</td>
<td>890101</td>
<td>&nbsp;</td>
<tr>
<td>Bradford protein assay</td>
<td>&nbsp;</td>
<td>Bio-Rad</td>
<td>500-0006</td>
<td>&nbsp;</td>
<tr>
<td>Carbonylcyanide p-trifluoromethoxyphenylhydrazone (FCCP)</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>C2920</td>
<td>&nbsp;</td>
<tr>
<td>Centrifuge 5804R</td>
<td>&nbsp;</td>
<td>Eppendorf</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Compressed nitrogen</td>
<td>&nbsp;</td>
<td>Local gas company</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>D-mannitol</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>M9647</td>
<td>&nbsp;</td>
<tr>
<td>Ethlyene-glycol-bis-tetraacetic acid (EGTA)</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>E3889</td>
<td>&nbsp;</td>
<tr>
<td>Ethylenediaminetetraacetic acid (EDTA)</td>
<td>&nbsp;</td>
<td>Bio-Rad</td>
<td>161-0728</td>
<td>&nbsp;</td>
<tr>
<td>Free fatty acid bovine serum albumin</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>A8806</td>
<td>&nbsp;</td>
<tr>
<td>Glutamic acid</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>G5889</td>
<td>&nbsp;</td>
<tr>
<td>HEPES sodium salt</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>H7006</td>
<td>&nbsp;</td>
<tr>
<td>Isotemp 3006D</td>
<td>&nbsp;</td>
<td>Fisher Scientific</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Magnesium chloride</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>M8266</td>
<td>&nbsp;</td>
<tr>
<td>Male Sprague Dawley Rats</td>
<td>&nbsp;</td>
<td>Harlan</td>
<td>300-500g</td>
<td>&nbsp;</td>
<tr>
<td>Malic acid</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>M9138</td>
<td>&nbsp;</td>
<tr>
<td>Minifuge</td>
<td>&nbsp;</td>
<td>ISC Bioexpress</td>
<td>C1301P</td>
<td>&nbsp;</td>
<tr>
<td>Oligomycin</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>O4876</td>
<td>&nbsp;</td>
<tr>
<td>Oxygen electrode disc</td>
<td>&nbsp;</td>
<td>Hansatech</td>
<td>S1</td>
<td>&nbsp;</td>
<tr>
<td>Oxygraph</td>
<td>&nbsp;</td>
<td>Hansatech</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Oxygraph Plus V1.01 Software</td>
<td>&nbsp;</td>
<td>Hansatech</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>pH-meter</td>
<td>&nbsp;</td>
<td>Mettler Toledo</td>
<td>1225506149</td>
<td>&nbsp;</td>
<tr>
<td>Phosphate-buffered saline (PBS)</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>P4417</td>
<td>&nbsp;</td>
<tr>
<td>Potassium chloride</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>P3911</td>
<td>&nbsp;</td>
<tr>
<td>Potassium phosphate</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>P8416</td>
<td>&nbsp;</td>
<tr>
<td>Potter-Elvehjem homogenizers</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>08-414-14A</td>
<td>&nbsp;</td>
<tr>
<td>PTFE (0.0125mm &#215; 25mm) membrane</td>
<td>&nbsp;</td>
<td>Hansatech</td>
<td>S4</td>
<td>&nbsp;</td>
<tr>
<td>SKIL 3320 drill press</td>
<td>&nbsp;</td>
<td>Hardware store</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Sucrose</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>S5016</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

mitochondrial isolation from skeletal muscle

As mitocôndrias são organelas controlar a vida ea morte da célula. Eles participam nos principais reações metabólicas, sintetizar a maior parte do ATP, e regular uma série de cascatas de sinalização 2,3. Pesquisadores passadas e actuais, mitocôndrias isoladas de ratos e camundongos tecidos como fígado, cérebro e coração 4,5. Nos últimos anos, muitos pesquisadores se concentraram em estudar a função mitocondrial dos músculos esqueléticos. Aqui, descrevemos um método que temos utilizado com sucesso para o isolamento de mitocôndrias de músculo esquelético 6. Nosso procedimento requer que todos os tampões e reagentes são feitas fresco e precisa de cerca de 250-500 mg de músculo esquelético. Foram estudadas mitocôndrias isoladas de ratos e camundongos gastrocnêmio e diafragma e os músculos extra-oculares de ratos. Concentração de proteína mitocondrial é medido com o ensaio de Bradford. É importante que as amostras mitocondrial ser mantida gelada durante a preparação e que estudos funcionais ser realizada dentro de um prazo relativamente curto (~ 1 hr). Respiração mitocondrial é medida usando polarografia com um eletrodo do tipo Clark (sistema Oxygraph) a 37 ° C 7. Calibração do eletrodo de oxigênio é um passo fundamental neste protocolo e deve ser realizada diariamente. Mitocôndrias isoladas (150 mg) são adicionados a 0,5 ml de tampão experimental (EB). Estado respiração 2 começa com adição de glutamato (5mM) e malato (2,5 mM). Então, difosfato de adenosina (ADP) (150 mM) é adicionado para começar estado 3. Oligomicina (1 mM), um bloqueador sintase ATPase, é usado para estimar o estado 4. Por último, carbonil cianeto de p-[trifluoromethoxy]-fenil-hidrazona (FCCP, 0,2 mM) é adicionado à measurestate 5, ou não atrelados a respiração 6. A relação de controle respiratório (RCR), a relação entre o estado 3 para o estado 4, é calculado depois de cada experimento. Um RCR ≥ 4 é considerado como evidência de uma preparação de mitocôndrias viáveis. Em resumo, apresentamos um método para o isolamento de mitocôndrias viáveis ​​a partir de músculos esqueléticos que podem ser usadas em bioquímica (por exemplo, atividade enzimática, imunodetecção, proteômica) estudos e funcionais (respiração mitocondrial).

Watch this Scientific Journal Video about Mitochondrial Isolation from Skeletal Muscle at JoVE.com

Mitochondrial Isolation from Skeletal Muscle

Este protocolo descreve um procedimento para estudar a respiração das mitocôndrias isoladas dos músculos esqueléticos. Este método foi adaptado de Scorrano<em&gt; Et al.</em&gt; (2007). O procedimento de isolamento mitocondrial requer cerca de 2 horas. A respiração mitocondrial pode ser concluído em cerca de 1 hora.

Isolamento mitocondrial do músculo esquelético

Mitochondria are organelles controlling the life and death of the cell. They participate in key metabolic reactions, synthesize most of the ATP, and ...

mitochondrial-isolation-from-skeletal-muscle

Research

JoVE Journal

Biology

28.8K visualizações.  University of Kentucky. Este protocolo descreve um procedimento para estudar a respiração das mitocôndrias isoladas dos músculos esqueléticos. Este método foi adaptado de Scorrano Et al. (2007). O procedimento de isolamento mitocondrial requer cerca de 2 horas. A respiração mitocondrial pode ser concluído em cerca de 1 hora.

Vídeo: Mitochondrial Isolation from Skeletal Muscle

Adult and Embryonic Skeletal Muscle Microexplant Culture and Isolation of Skeletal Muscle Stem Cells

Cultured embryonic and adult skeletal muscle cells have a number of different uses. The micro-dissected explants technique described in this chapter is a robust and reliable method for isolating relatively large numbers of proliferative skeletal muscle cells from juvenile, adult or embryonic muscles as a source of skeletal muscle stem cells. The authors have used micro-dissected explant cultures to analyse the growth characteristics of skeletal muscle cells in wild-type and dystrophic muscles. Each of the components of tissue growth, namely cell survival, proliferation, senescence and differentiation can be analysed separately using the methods described here. The net effect of all components of growth can be established by means of measuring explant outgrowth rates. The micro-explant method can be used to establish primary cultures from a wide range of different muscle types and ages and, as described here, has been adapted by the authors to enable the isolation of embryonic skeletal muscle precursors.
Uniquely, micro-explant cultures have been used to derive clonal (single cell origin) skeletal muscle stem cell (SMSc) lines which can be expanded and used for in vivo transplantation. In vivo transplanted SMSc behave as functional, tissue-specific, satellite cells which contribute to skeletal muscle fibre regeneration but which are also retained (in the satellite cell niche) as a small pool of undifferentiated stem cells which can be re-isolated into culture using the micro-explant method.

The micro-dissected explants technique is a robust and reliable method for isolating proliferative skeletal muscle cells from juvenile, adult or embryonic muscles as a source of skeletal muscle stem cells. Uniquely, these cells have been clonally derived to produce skeletal muscle stem cell lines used for in vivo transplantation.

Adultas e embrionárias Cultura Microexplant Músculo Esquelético e isolamento de células-tronco musculares

Cultured embryonic and adult skeletal muscle cells have a number of different uses. The micro-dissected explants technique described in this chapter is a ...

Biologia

Purification of Progenitors from Skeletal Muscle

Skeletal muscle contains multiple progenitor populations of distinct embryonic origins and developmental potential. Myogenic progenitors, usually residing in a "satellite cell position" between the myofiber plasma membrane and the laminin-rich basement membrane that ensheaths it, are self-renewing cells that are solely committed to the myogenic lineage1,2. We have recently described a second class of vessel associated progenitors that can generate myofibroblasts and white adipocytes, which responds to damage by efficiently entering proliferation and provides trophic support to myogenic cells during tissue regeneration3,4. One of the most trusted assays to determine the developmental and regenerative potential of a given cell population relies on their isolation and transplantation5-7. To this end we have optimized protocols for their purification by flow cytometry from enzymatically dissociated muscle, which we will outline in this article. The populations obtained using this method will contain either myogenic or fibro/adipogenic colony forming cells: no other cell types are capable of expanding in vitro or surviving in vivo delivery. However, when these populations are used immediately after the sort for molecular analysis (e.g qRT-PCR) one must keep in mind that the freshly sorted subsets may contain other contaminant cells that lack the ability of forming colonies or engrafting recipients.

Method for the enzymatic dissociation, surface labeling and purification by flow cytometry of fibro/adipogenic and myogenic progenitors from murine skeletal muscle.

Purificação de Progenitores do músculo esquelético

Skeletal muscle contains multiple progenitor populations of distinct embryonic origins and developmental potential. Myogenic progenitors, usually residing ...

Isolation and Culture of Individual Myofibers and their Satellite Cells from Adult Skeletal Muscle

Muscle regeneration in the adult is performed by resident stem cells called satellite cells. Satellite cells are defined by their position between the basal lamina and the sarcolemma of each myofiber. Current knowledge of their behavior heavily relies on the use of the single myofiber isolation protocol. In 1985, Bischoff described a protocol to isolate single live fibers from the Flexor Digitorum Brevis (FDB) of adult rats with the goal to create an in vitro system in which the physical association between the myofiber and its stem cells is preserved 1. In 1995, Rosenblattmodified the Bischoff protocol such that myofibers are singly picked and handled separately after collagenase digestion instead of being isolated by gravity sedimentation 2, 3. The Rosenblatt or Bischoff protocol has since been adapted to different muscles, age or conditions 3-6. The single myofiber isolation technique is an indispensable tool due its unique advantages. First, in the single myofiber protocol, satellite cells are maintained beneath the basal lamina. This is a unique feature of the protocol as other techniques such as Fluorescence Activated Cell Sorting require chemical and mechanical tissue dissociation 7. Although the myofiber culture system cannot substitute for in vivo studies, it does offer an excellent platform to address relevant biological properties of muscle stem cells. Single myofibers can be cultured in standard plating conditions or in floating conditions. Satellite cells on floating myofibers are subjected to virtually no other influence than the myofiber environment. Substrate stiffness and coating have been shown to influence satellite cells' ability to regenerate muscles 8, 9 so being able to control each of these factors independently allows discrimination between niche-dependent and -independent responses. Different concentrations of serum have also been shown to have an effect on the transition from quiescence to activation. To preserve the quiescence state of its associated satellite cells, fibers should be kept in low serum medium 1-3. This is particularly useful when studying genes involved in the quiescence state. In serum rich medium, satellite cells quickly activate, proliferate, migrate and differentiate, thus mimicking the in vivo regenerative process 1-3. The system can be used to perform a variety of assays such as the testing of chemical inhibitors; ectopic expression of genes by virus delivery; oligonucleotide based gene knock-down or live imaging. This video article describes the protocol currently used in our laboratory to isolate single myofibers from the Extensor Digitorum Longus (EDL) muscle of adult mice (6-8 weeks old).

Isolation and culture of myofibers is the gold standard in vitro system to study the transition of satellite cells through quiescence, activation and differentiation. Importantly, the single myofiber culture system preserves the myofiber/stem cell association, which is an essential component of the muscle stem cell niche.

Isolamento e Cultura de miofibras individuais e suas células satélites do músculo esquelético

Muscle  regeneration in the adult is performed by resident stem cells called satellite  cells. Satellite cells are defined by  their position between the ...

Isolation of Blood-vessel-derived Multipotent Precursors from Human Skeletal Muscle

Since the discovery of mesenchymal stem/stromal cells (MSCs), the native identity and localization&#160;of MSCs have been obscured by their retrospective isolation in culture. Recently, using fluorescence-activated cell sorting (FACS), we and other researchers prospectively identified and purified three subpopulations of multipotent precursor cells associated with the vasculature of human skeletal muscle. These three cell populations: myogenic endothelial cells (MECs), pericytes (PCs), and adventitial cells (ACs), are localized respectively to the three structural layers of blood vessels: intima, media, and adventitia. All of these human blood-vessel-derived stem cell (hBVSC) populations not only express classic MSC markers but also possess mesodermal developmental potentials similar to typical MSCs. Previously, MECs, PCs, and ACs have been isolated through distinct protocols and subsequently characterized in separate studies. The current isolation protocol, through modifications to the isolation process and adjustments in the selective cell surface markers, allows us to simultaneously purify all three hBVSC subpopulations by FACS from a single human muscle biopsy. This new method will not only streamline the isolation of multiple BVSC subpopulations but also facilitate future clinical applications of hBVSCs for distinct therapeutic purposes.

Blood vessels within human skeletal muscle harbor several multi-lineage precursor populations that are ideal for regenerative applications. This isolation method allows simultaneous purification of three multipotent precursor cell populations respectively from three structural layers of blood vessels: myogenic endothelial cells from intima, pericytes from media, and adventitial cells from adventitia.

Isolamento de Blood-derivado do navio Multipotentes Precursores do músculo-esquelético humano

Since the discovery of mesenchymal stem/stromal cells (MSCs), the native identity and localization&#160;of MSCs have been obscured by their retrospective ...

Isolation of Mitochondria from Minimal Quantities of Mouse Skeletal Muscle for High Throughput Microplate Respiratory Measurements

Dysfunctional skeletal muscle mitochondria play a role in altered metabolism observed with aging, obesity and Type II diabetes. Mitochondrial respirometric assays from isolated mitochondrial preparations allow for the assessment of mitochondrial function, as well as determination of the mechanism(s) of action of drugs and proteins that modulate metabolism. Current isolation procedures often require large quantities of tissue to yield high quality mitochondria necessary for respirometric assays. The methods presented herein describe how high quality purified mitochondria (~ 450 &#181;g) can be isolated from minimal quantities (~75-100 mg) of mouse skeletal muscle for use in high throughput respiratory measurements. We determined that our isolation method yields 92.5&#177; 2.0% intact mitochondria by measuring citrate synthase activity spectrophotometrically. In addition, Western blot analysis in isolated mitochondria resulted in the faint expression of the cytosolic protein, GAPDH, and the robust expression of the mitochondrial protein, COXIV. The absence of a prominent GAPDH band in the isolated mitochondria is indicative of little contamination from non-mitochondrial sources during the isolation procedure. Most importantly, the measurement of O2 consumption rate with micro-plate based technology and determining the respiratory control ratio (RCR) for coupled respirometric assays shows highly coupled (RCR; &#62;6 for all assays) and functional mitochondria. In conclusion, the addition of a separate mincing step and significantly reducing motor driven homogenization speed of a previously reported method has allowed the isolation of high quality and purified mitochondria from smaller quantities of mouse skeletal muscle that results in highly coupled mitochondria that respire with high function during microplate based respirometirc assays.

Here, we present a modification of a previously reported method that allows for the isolation of high quality and purified mitochondria from smaller quantities of mouse skeletal muscle. This procedure results in highly coupled mitochondria that respire with high function during microplate based respirometirc assays.

Isolamento de mitocôndrias de quantidades mínimas de Rato Músculo Esquelético para medições High Throughput Microplate respiratórias

Dysfunctional skeletal muscle mitochondria play a role in altered metabolism observed with aging, obesity and Type II diabetes. Mitochondrial ...

Isolation of Intact Mitochondria from Skeletal Muscle by Differential Centrifugation for High-resolution Respirometry Measurements

Mitochondria are involved in cellular energy metabolism and use oxygen to produce energy in the form of adenosine triphosphate (ATP). Differential centrifugation at low- and high-speed is commonly used to isolate mitochondria from tissues and cultured cells. Crude mitochondrial fractions obtained by differential centrifugation are used for respirometry measurements. The differential centrifugation technique is based on the separation of organelles according to their size and sedimentation velocity. The isolation of mitochondria is performed immediately after tissue harvesting. The tissue is immersed in an ice-cold homogenization medium, minced using scissors and homogenized in a glass homogenizer with a loose-fitting pestle. The differential centrifugation technique is efficient, fast and inexpensive and the mitochondria obtained by differential centrifugation are pure enough for respirometry assays. Some of the limitations and disadvantages of isolated mitochondria, based on differential centrifugation, are that the mitochondria can be damaged during the homogenization and isolation procedure and that large amounts of the tissue biopsy or cultured cells are required for the mitochondrial isolation.

Here, a quadriceps muscle specimen is taken from an anaesthetized pig and mitochondria are isolated by differential centrifugation. Then, the respiratory rates of mitochondrial respiratory chain complexes I, II and IV are determined using high-resolution respirometry.

Isolamento de mitocôndrias intactas de Músculo Esquelético por centrifugação diferencial para medições Respirometria de alta resolução

Mitochondria are involved in cellular energy metabolism and use oxygen to produce energy in the form of adenosine triphosphate (ATP). Differential ...

Isolation and Characterization of Exosomes from Skeletal Muscle Fibroblasts

Exosomes are small extracellular vesicles released by virtually all cells and secreted in all biological fluids. Many methods have been developed for the isolation of these vesicles, including ultracentrifugation, ultrafiltration, and size exclusion chromatography. However, not all are suitable for large scale exosome purification and characterization. Outlined here is a protocol for establishing cultures of primary fibroblasts isolated from adult mouse skeletal muscles, followed by purification and characterization of exosomes from the culture media of these cells. The method is based on the use of sequential centrifugation steps followed by sucrose density gradients. Purity of the exosomal preparations is then validated by western blot analyses using a battery of canonical markers (i.e., Alix, CD9, and CD81). The protocol describes how to isolate and concentrate bioactive exosomes for electron microscopy, mass spectrometry, and uptake experiments for functional studies. It can easily be scaled up or down and adapted for exosome isolation from different cell types, tissues, and biological fluids.

This protocol illustrates the 1) the isolation and culture of primary fibroblasts from the adult mouse gastrocnemius muscle as well as 2) purification and characterization of exosomes using a differential ultracentrifugation method combined with sucrose density gradients followed by western blot analyses.

Isolamento e Caracterização de Exossomos de Fibroblastos de Músculo Esquelético

Exosomes are small extracellular vesicles released by virtually all cells and secreted in all biological fluids. Many methods have been developed for the ...

Isolation of Human Ventricular Cardiomyocytes from Vibratome-Cut Myocardial Slices

The isolation of ventricular cardiac myocytes from animal and human hearts is a fundamental method in cardiac research. Animal cardiomyocytes are commonly isolated by coronary perfusion with digestive enzymes. However, isolating human cardiomyocytes is challenging because human myocardial specimens usually do not allow for coronary perfusion, and alternative isolation protocols result in poor yields of viable cells. In addition, human myocardial specimens are rare and only regularly available at institutions with on-site cardiac surgery. This hampers the translation of findings from animal to human cardiomyocytes. Described here is a reliable protocol that enables efficient isolation of ventricular myocytes from human and animal myocardium. To increase the surface-to-volume ratio while minimizing cell damage, myocardial tissue slices 300 &#181;m thick are generated from myocardial specimens with a vibratome. Tissue slices are then digested with protease and collagenase. Rat myocardium was used to establish the protocol and quantify yields of viable, calcium-tolerant myocytes by flow-cytometric cell counting. Comparison with the commonly used tissue-chunk method showed significantly higher yields of rod-shaped cardiomyocytes (41.5 &#177; 11.9 vs. 7.89 &#177; 3.6%, p &#60; 0.05). The protocol was translated to failing and non-failing human myocardium, where yields were similar as in rat myocardium and, again, markedly higher than with the tissue-chunk method (45.0 &#177; 15.0 vs. 6.87 &#177; 5.23 cells/mg, p &#60; 0.05). Notably, with the protocol presented it is possible to isolate reasonable numbers of viable human cardiomyocytes (9&#8211;200 cells/mg) from minimal amounts of tissue (&#60;50 mg). Thus, the method is applicable to healthy and failing myocardium from both human and animal hearts. Furthermore, it is possible to isolate excitable and contractile myocytes from human tissue specimens stored for up to 36 h in cold cardioplegic solution, rendering the method particularly useful for laboratories at institutions without on-site cardiac surgery.

Presented is a protocol for the isolation of human and animal ventricular cardiomyocytes from vibratome-cut myocardial slices. High yields of calcium-tolerant cells (up to 200 cells/mg) can be obtained from small amounts of tissue (&#60;50 mg). The protocol is applicable to myocardium exposed to cold ischemia for up to 36 h.

Isolamento de Cardiomiócitos Ventriculares Humanos de fatias de miocárdio cortadas por vibratome

The isolation of ventricular cardiac myocytes from animal and human hearts is a fundamental method in cardiac research. Animal cardiomyocytes are commonly ...

Isolation of Mitochondria from Mouse Skeletal Muscle for Respirometric Assays

Most of the cell&#39;s energy is obtained through the degradation of glucose, fatty acids, and amino acids by different pathways that converge on the mitochondrial oxidative phosphorylation (OXPHOS) system, which is regulated in response to cellular demands. The lipid molecule Coenzyme Q (CoQ) is essential in this process by transferring electrons to complex III in the electron transport chain (ETC) through constant oxidation/reduction cycles. Mitochondria status and, ultimately, cellular health can be assessed by measuring ETC oxygen consumption using respirometric assays. These studies are typically performed in established or primary cell lines that have been cultured for several days. In both cases, the respiration parameters obtained may have deviated from normal physiological conditions in&#160;any given organ or tissue.
Additionally, the intrinsic characteristics of cultured single fibers isolated from skeletal muscle impede this type of analysis. This paper presents an updated and detailed protocol for the analysis of respiration in freshly isolated mitochondria from mouse skeletal muscle. We also provide solutions to potential problems that could arise at any step of the process. The method presented here could be applied to compare oxygen consumption rates in diverse transgenic mouse models and study the mitochondrial response to drug treatments or other factors such as aging or sex. This is a feasible method to respond to crucial questions about mitochondrial bioenergetics metabolism and regulation.

Here, we describe a detailed method for mitochondria isolation from mouse skeletal muscle and the subsequent analysis of respiration by Oxygen Consumption Rate (OCR) using microplate-based respirometric assays. This pipeline can be applied to study the effects of multiple environmental or genetic interventions on mitochondrial metabolism.

Isolamento das Mitocôndrias do Músculo Esquelético do Rato para Ensaios Respirométricos

Most of the cell&#39;s energy is obtained through the degradation of glucose, fatty acids, and amino acids by different pathways that converge on the ...

Análise microscópica confocal das mitocôndrias do músculo de ratos

Analysis of the Mitochondrial Density and Longitudinal Distribution in Rat Live-Skeletal Muscle Fibers by Confocal Microscopy

The mitochondrion is an organelle that can be elongated, fragmented, and renovated according to the metabolic requirements of the cells. The remodeling of the mitochondrial network allows healthy mitochondria to meet cellular demands; however, the loss of this capacity has been related to the development or progression of different pathologies. In skeletal muscle, mitochondrial density and distribution changes are observed in physiological and pathological conditions such as exercise, aging, and obesity, among others. Therefore, the study of the mitochondrial network may provide a better understanding of mechanisms related to those conditions.
Here, a protocol for mitochondria imaging of live-skeletal muscle fibers from rats is described. Fibers are manually dissected in a relaxing solution and incubated with a fluorescent live-cell imaging indicator of mitochondria (tetramethylrhodamine ethyl ester, TMRE). The mitochondria signal is recorded by confocal microscopy using the XYZ scan mode to obtain confocal images of the intermyofibrillar mitochondrial (IMF) network. After that, the confocal images are processed by thresholding and binarization. The binarized confocal image accounts for the positive pixels for mitochondria, which are then counted to obtain the mitochondrial density. The mitochondrial network in skeletal muscle is characterized by a high density of IMF population, which has a periodic longitudinal distribution similar to that of T-tubules (TT).&#160;The Fast Fourier Transform (FFT) is a standard analysis technique performed to evaluate the distribution of TT that allows finding the distribution frequency and the level of their organization. In this protocol, the implementation of the FFT algorithm is described for the analysis of the longitudinal mitochondrial distribution in skeletal muscle.

Autor em destaque: Remodelação mitocondrial no músculo esquelético 

Here, we present a protocol to analyze changes in mitochondrial density and longitudinal distribution by live-skeletal muscle imaging using confocal microscopy for mitochondrial network scanning.

Análise da densidade mitocondrial e distribuição longitudinal em fibras musculares esqueléticas vivas de ratos por microscopia confocal

The mitochondrion is an organelle that can be elongated, fragmented, and renovated according to the metabolic requirements of the cells. The remodeling of ...

Methods Article

Isolamento mitocondrial do músculo esquelético