This work was supported by funding from the Department of Pathology and Laboratory Medicine, University of Cincinnati, College of Medicine, to Dr. Onur Kanisicak; a grant from the National Institutes of Health (R01HL148598) to Dr. Onur Kanisicak.&#160;Dr. Onur Kanisicak is supported by the American Heart Association Career Development Award (18CDA34110117). Dr. Perwez Alam is supported by the American Heart Association postdoctoral grant (AHA_20POST35200267). Dr Malina J. Ivey is supported by an NIH T32 grant (HL 125204-06A1).

All experiments should be performed in accordance with the guidelines of the Guide for the Care and Use of Laboratory Animals published by the U.S. National Institute of Health (NIH). All protocols displayed in the video were approved by the Institutional Animal Care and Use Committee (IACUC) of the University of Cincinnati, College of Medicine.
1. Preparation before heart extraction from adult mice (and rats)
<ol>
	<li>Prepare the corresponding perfusion, enzyme, and stop solutions, accordi...

<ol>
	<li>van Amerongen, M. J., Engel, F. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Features+of+cardiomyocyte+proliferation+and+its+potential+for+cardiac+regeneration.">Features of cardiomyocyte proliferation and its potential for cardiac regeneration.</a> Journal of Cellular and Molecular Medicine. 12, 2233-2244 (2008).</li><li>Parente, V., 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=Hypoxia/reoxygenation+cardiac+injury+and+regeneration+in+zebrafish+adult+heart.">Hypoxia/reoxygenation cardiac injury and regeneration in zebrafish adult heart.</a> PLoS One. 8, 53748 (2013).</li><li>Wang, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+regenerative+capacity+of+zebrafish+reverses+cardiac+failure+caused+by+genetic+cardiomyocyte+depletion.">The regenerative capacity of zebrafish reverses cardiac failure caused by genetic cardiomyocyte depletion.</a> Development. 138, 3421-3430 (2011).</li><li>Gonzalez-Rosa, J. M., Martin, V., Peralta, M., Torres, M., Mercader, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extensive+scar+formation+and+regression+during+heart+regeneration+after+cryoinjury+in+zebrafish.">Extensive scar formation and regression during heart regeneration after cryoinjury in zebrafish.</a> Development. 138, 1663-1674 (2011).</li><li>Graham, E. 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,+culture,+and+functional+characterization+of+adult+mouse+cardiomyoctyes.">Isolation, culture, and functional characterization of adult mouse cardiomyoctyes.</a> Journal of Visualized Experiments. , e50289 (2013).</li><li>Brette, F., Orchard, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=T-tubule+function+in+mammalian+cardiac+myocytes.">T-tubule function in mammalian cardiac myocytes.</a> Circulation Research. 92, 1182-1192 (2003).</li><li>M&#252;ller, J. G., 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=Differential+regulation+of+the+cardiac+sodium+calcium+exchanger+promoter+in+adult+and+neonatal+cardiomyocytes+by+Nkx2.5+and+serum+response+factor.">Differential regulation of the cardiac sodium calcium exchanger promoter in adult and neonatal cardiomyocytes by Nkx2.5 and serum response factor.</a> Journal of Molecular and Cellular Cardiology. 34, 807-821 (2002).</li><li>Zhou, H., 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=Exosomes+in+ischemic+heart+disease:+novel+carriers+for+bioinformation.">Exosomes in ischemic heart disease: novel carriers for bioinformation.</a> Biomedicine &amp; Pharmacotherapy. 120, 109451 (2019).</li><li>Wu, Y. S., Zhu, B., Luo, A. L., Yang, L., Yang, C. <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+Cardiokines+in+Heart+Diseases:+Beneficial+or+Detrimental.">The Role of Cardiokines in Heart Diseases: Beneficial or Detrimental.</a> BioMed Research International. 2018, 8207058 (2018).</li><li>Eppenberger, H. M., Hertig, C., Eppenberger-Eberhardt, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adult+rat+cardiomyocytes+in+culture+A+model+system+to+study+the+plasticity+of+the+differentiated+cardiac+phenotype+at+the+molecular+and+cellular+levels.">Adult rat cardiomyocytes in culture A model system to study the plasticity of the differentiated cardiac phenotype at the molecular and cellular levels.</a> Trends in Cardiovascular Medicine. 4, 187-193 (1994).</li><li>Alam, P., 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=Inhibition+of+Senescence-Associated+Genes+Rb1+and+Meis2+in+Adult+Cardiomyocytes+Results+in+Cell+Cycle+Reentry+and+Cardiac+Repair+Post-Myocardial+Infarction.">Inhibition of Senescence-Associated Genes Rb1 and Meis2 in Adult Cardiomyocytes Results in Cell Cycle Reentry and Cardiac Repair Post-Myocardial Infarction.</a> Journal of the American Heart Association. 8, 012089 (2019).</li><li>Arif, 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=MicroRNA-210-mediated+proliferation,+survival,+and+angiogenesis+promote+cardiac+repair+post+myocardial+infarction+in+rodents.">MicroRNA-210-mediated proliferation, survival, and angiogenesis promote cardiac repair post myocardial infarction in rodents.</a> Journal of Molecular Medicine. 95, 1369-1385 (2017).</li><li>Rosenthal, N., Brown, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+mouse+ascending:+perspectives+for+human-disease+models.">The mouse ascending: perspectives for human-disease models.</a> Nature Cell Biology. 9, 993-999 (2007).</li><li>Nippert, F., Schreckenberg, R., Schl&#252;ter, K. D. <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+Cultivation+of+Adult+Rat+Cardiomyocytes.">Isolation and Cultivation of Adult Rat Cardiomyocytes.</a> Journal of Visualized Experiments. , e56634 (2017).</li><li>Judd, J., Lovas, J., Huang, G. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation,+Culture+and+Transduction+of+Adult+Mouse+Cardiomyocytes.">Isolation, Culture and Transduction of Adult Mouse Cardiomyocytes.</a> Journal of Visualized Experiments. , e54012 (2016).</li><li>Ackers-Johnson, 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=A+Simplified,+Langendorff-Free+Method+for+Concomitant+Isolation+of+Viable+Cardiac+Myocytes+and+Nonmyocytes+From+the+Adult+Mouse+Heart.">A Simplified, Langendorff-Free Method for Concomitant Isolation of Viable Cardiac Myocytes and Nonmyocytes From the Adult Mouse Heart.</a> Circulation Research. 119, 909-920 (2016).</li><li>Li, D., Wu, J., Bai, Y., Zhao, X., Liu, L. <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+culture+of+adult+mouse+cardiomyocytes+for+cell+signaling+and+in+vitro+cardiac+hypertrophy.">Isolation and culture of adult mouse cardiomyocytes for cell signaling and in vitro cardiac hypertrophy.</a> Journal of Visualized Experiments. , e51357 (2014).</li><li>Pinz, I., Zhu, M., Mende, U., Ingwall, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+improved+isolation+procedure+for+adult+mouse+cardiomyocytes.">An improved isolation procedure for adult mouse cardiomyocytes.</a> Cell Biochemistry and Biophysics. 61, 93-101 (2011).</li><li>O'Connell, T. D., Rodrigo, M. C., Simpson, P. C. <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+culture+of+adult+mouse+cardiac+myocytes.">Isolation and culture of adult mouse cardiac myocytes.</a> Methods in Molecular Biology. 357, 271-296 (2007).</li><li>Dou, Y., Arlock, P., Arner, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blebbistatin+specifically+inhibits+actin-myosin+interaction+in+mouse+cardiac+muscle.">Blebbistatin specifically inhibits actin-myosin interaction in mouse cardiac muscle.</a> American Journal of Physiology: Cell Physiology. 293, 1148-1153 (2007).</li><li>Kabaeva, Z., Zhao, M., Michele, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blebbistatin+extends+culture+life+of+adult+mouse+cardiac+myocytes+and+allows+efficient+and+stable+transgene+expression.">Blebbistatin extends culture life of adult mouse cardiac myocytes and allows efficient and stable transgene expression.</a> American Journal of Physiology: Heart and Circulatory Physiology. 294, 1667-1674 (2008).</li><li>Sellin, L. C., McArdle, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiple+effects+of+2,3-butanedione+monoxime.">Multiple effects of 2,3-butanedione monoxime.</a> Pharmacology &amp; Toxicology. 74, 305-313 (1994).</li></ol>

There is a critical need to establish a protocol for adult cardiomyocyte isolation and long-term culture to perform cell-specific mechanistic studies. There are only a few reports discussing adult CM isolation protocols, and even fewer of them are used for long-term culture of adult mice CM15,16,17. It is been shown that the adult rat CM has a higher tolerance to in vitro culture than the adult mice CM10<...

Cardiac diseases are one of the leading causes of death worldwide. Almost all types of cardiac injury result in a significant loss of adult cardiomyocytes (CMs). Adult mammalian hearts are unable to repair their cardiac injury due to the senescent nature of the adult CM1. Thus, any insult to the adult mammalian heart results in a permanent loss of CMs, leading to reduced cardiac function and heart failure. Unlike adult mammals, small animals like zebrafish and newt hearts can regenerate their cardiac injury through existing CM proliferation2,3,4. A worldwide effort is ongoing to find a novel therapeutic intervention for cardiac injury via both proliferative and non-proliferative approaches. In past decades, various types of genetic mouse models have been developed to study cardiac injury and repair. However, using in vivo animal models continues to be an expensive approach with the additional complexity to decipher a cell-autonomous mechanism from secondary effects. Besides, in vivo systems are challenging to analyze CM specific effects of a pharmacological intervention that induces cardioprotective signaling from the CM.
Moreover, the long-term culture of adult CMs is necessary to perform CM proliferation analyses. CM proliferation assays require a minimum of 4-5 days for cells to be induced into the cell cycle and to obtain accurate data after that. Additionally, studies that utilize isolated CMs for electrophysiological studies, drug screening, toxicity studies, and Ca++ homeostasis studies are all in need of an improved culture system5,6,7. Furthermore, recent studies show the cardioprotective significance of cytokines secreted from CMs (cardiokines)8,9. In order to investigate the therapeutic role and molecular mechanism of these cardiokines during heart repair and regeneration, a prolonged culture is required.
Adult rat CMs are robust enough for single-cell isolation and long-term culture in an in vitro system10,11,12. However, adult mouse CMs are of great interest for in vitro assays, due to the availability of a variety of genetically modified mouse models, which allows for the design and execution of various innovative analyses that are not possible with rat CM13. In contrast to adult rat CM isolation, it is quite challenging to obtain a single-cell suspension from adult mouse hearts, and the long-term culture of adult mouse CMs in culture is even more challenging.
Adult CM isolation from mouse and rat hearts using a Langendorff system has previously been established to study CM function5,14,15. Here, we have described in detail the protocols for adult CM isolation from both rats and mice, as well as a modified long-term culture, transfection, and CM proliferation of isolated cells.

<table>
	<tbody>
		<tr>
			<td>2,3-Butane Dione monoxime</td>
			<td>Sigma-Aldrich</td>
			<td>B-0753</td>
			<td></td>
		</tr>
		<tr>
			<td>Blebbistatin</td>
			<td>APExBIO</td>
			<td>B1387</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine serum albumin</td>
			<td>Sigma-Aldrich</td>
			<td>A3059</td>
			<td></td>
		</tr>
		<tr>
			<td>CaCl2</td>
			<td>Sigma-Aldrich</td>
			<td>449709</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell culture plate</td>
			<td>Corning Costar</td>
			<td>3526</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell strainer</td>
			<td>BD Biosciences</td>
			<td>352360</td>
			<td></td>
		</tr>
		<tr>
			<td>Cel-miR-67</td>
			<td>Dharmacon</td>
			<td>CN-001000-01-50</td>
			<td></td>
		</tr>
		<tr>
			<td>Collagenase type2</td>
			<td>Worthington</td>
			<td>LS004177</td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable Graduated Transfer Pipettes</td>
			<td>Fisherbrand</td>
			<td>13-711-20</td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable polystyrene weighing dishes</td>
			<td>Sigma-Aldrich</td>
			<td>Z154881-500EA</td>
			<td></td>
		</tr>
		<tr>
			<td>Dulbecco&#39;s Modified Eagle&#39;s medium</td>
			<td>Thermo Scientific</td>
			<td>SH30022.01</td>
			<td></td>
		</tr>
		<tr>
			<td>EdU</td>
			<td>Life Technologies</td>
			<td>C10337</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal bovine serum</td>
			<td>Corning</td>
			<td>35-015-CV</td>
			<td></td>
		</tr>
		<tr>
			<td>Fine Point High Precision Forceps</td>
			<td>Fisherbrand</td>
			<td>22-327379</td>
			<td></td>
		</tr>
		<tr>
			<td>Glucose</td>
			<td>Sigma-Aldrich</td>
			<td>G-5400</td>
			<td></td>
		</tr>
		<tr>
			<td>Hemocytometer</td>
			<td>Hausser Scientific</td>
			<td>1483</td>
			<td></td>
		</tr>
		<tr>
			<td>Heparin</td>
			<td>Sagent Pharmaceuticals</td>
			<td>PSLAB-018285-02</td>
			<td></td>
		</tr>
		<tr>
			<td>HEPES</td>
			<td>Sigma-Aldrich</td>
			<td>H3375</td>
			<td></td>
		</tr>
		<tr>
			<td>High Precision Straight Broad Strong Point Tweezers/Forceps</td>
			<td>Fisherbrand</td>
			<td>12-000-128</td>
			<td></td>
		</tr>
		<tr>
			<td>Hyaluronidase</td>
			<td>Sigma</td>
			<td>H3506</td>
			<td></td>
		</tr>
		<tr>
			<td>Insulin</td>
			<td>Sigma-Aldrich</td>
			<td>I0516-5ML</td>
			<td></td>
		</tr>
		<tr>
			<td>K2HPO4</td>
			<td>Sigma-Aldrich</td>
			<td>P-8281</td>
			<td></td>
		</tr>
		<tr>
			<td>KCl</td>
			<td>Sigma-Aldrich</td>
			<td>746436</td>
			<td></td>
		</tr>
		<tr>
			<td>Light Microscope</td>
			<td>Nikon</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Lipofectamine RNAiMAX</td>
			<td>Life Technologies</td>
			<td>13778-150</td>
			<td></td>
		</tr>
		<tr>
			<td>MgSO4</td>
			<td>Sigma-Aldrich</td>
			<td>M-2643</td>
			<td></td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Sigma-Aldrich</td>
			<td>S9888</td>
			<td></td>
		</tr>
		<tr>
			<td>NaOH</td>
			<td>Fisher Scientific</td>
			<td>S318-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Natural Mouse Laminin</td>
			<td>Invitrogen</td>
			<td>23017-015</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin/Streptomycin</td>
			<td>Corning</td>
			<td>30-002-CI</td>
			<td></td>
		</tr>
		<tr>
			<td>Pentobarbital</td>
			<td>Henry Schein</td>
			<td>24352</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate buffered saline</td>
			<td>Life Technologies</td>
			<td>20012-027</td>
			<td></td>
		</tr>
		<tr>
			<td>Protease XIV</td>
			<td>Sigma-Aldrich</td>
			<td>P5147-1G</td>
			<td></td>
		</tr>
		<tr>
			<td>Selenium</td>
			<td>Sigma-Aldrich</td>
			<td>229865+5G</td>
			<td></td>
		</tr>
		<tr>
			<td>siMeis2</td>
			<td>Dharmacon</td>
			<td>s161030</td>
			<td></td>
		</tr>
		<tr>
			<td>siRb1</td>
			<td>Dharmacon</td>
			<td>s128325</td>
			<td></td>
		</tr>
		<tr>
			<td>Straight Blunt/SharpDissecting Scissors</td>
			<td>Fisher Scientific</td>
			<td>28252</td>
			<td></td>
		</tr>
		<tr>
			<td>Straight Very Fine Precision Tip Forceps</td>
			<td>Fisherbrand</td>
			<td>16-100-120</td>
			<td></td>
		</tr>
		<tr>
			<td>Taurine</td>
			<td>Sigma-Aldrich</td>
			<td>T0625</td>
			<td></td>
		</tr>
		<tr>
			<td>Transferrin</td>
			<td>Sigma-Aldrich</td>
			<td>T8158-100MG</td>
			<td></td>
		</tr>
		<tr>
			<td>Ultra-smooth, beveled-edge finish scissor</td>
			<td>Fisherbrand</td>
			<td>22-079-747</td>
			<td></td>
		</tr>
		<tr>
			<td>Water Bath</td>
			<td>Fisher Scientific</td>
			<td>3006S</td>
			<td></td>
		</tr>
	</tbody>
</table>

isolation, transfection, and long-term culture of adult mouse and rat cardiomyocytes

Ex vivo culture of the adult mammalian cardiomyocytes (CMs) presents the most relevant experimental system for the in vitro study of cardiac biology. Adult mammalian CMs are terminally differentiated cells with minimal proliferative capacity. The post-mitotic state of adult CMs not only restricts cardiomyocyte cell cycle progression but also limits the efficient culture of CMs. Moreover, the long-term culture of adult CMs is necessary for many studies, such as CM proliferation and analysis of gene expression.
The mouse and the rat are the two most preferred laboratory animals to be used for cardiomyocyte isolation. While the long-term culture of rat CMs is possible, adult mouse CMs are susceptible to death and cannot be cultured more than five days under normal conditions. Therefore, there is a critical need to optimize the cell isolation and long-term culture protocol for adult murine CMs. With this modified protocol, it is possible to successfully isolate and culture both adult mouse and rat CMs for more than 20 days. Moreover, the siRNA transfection efficiency of isolated CM is significantly increased compared to previous reports. For adult mouse CM isolation, the Langendorff perfusion method is utilized with an optimal enzyme solution and sufficient time for complete extracellular matrix dissociation. In order to obtain pure ventricular CMs, both atria were dissected and discarded before proceeding with the disassociation and plating. Cells were dispersed on a laminin coated plate, which allowed for efficient and rapid attachment. CMs were allowed to settle for 4-6 h before siRNA transfection. Culture media was refreshed every 24 h for 20 days, and subsequently, CMs were fixed and stained for cardiac-specific markers such as Troponin and markers of cell cycle such as KI67.

The current modified protocol allows efficient isolation and culture of rat and mice CMs in vitro. For rat CM isolation, a total of 3 adult (12-week-old) male Fischer 344 rats were used in the procedure. Figure 1 shows the surgical apparatus and isolation setups that are required in the procedure; each part has been marked and described in the figure legend. Collagenase type 2 was used for digestion, which yields a high quantity of high quality CMs from successful isolation (<strong class="x...

Watch this Scientific Journal Video about Isolation, Transfection, and Long-Term Culture of Adult Mouse and Rat Cardiomyocytes at JoVE.com

Isolation, Transfection, and Long-Term Culture of Adult Mouse and Rat Cardiomyocytes

Here, we present a protocol for the isolation, transfection, and long-term culture of adult mouse and rat cardiomyocytes.

Ex vivo culture of the adult mammalian cardiomyocytes (CMs) presents the most relevant experimental system for the in vitro study of cardiac biology. ...

The objective of this video is to demonstrate a standardized protocol for adult cardiomyocytes isolation, long-term culture and transfection. Isolating and culturing cardiomyocytes from mouse or rat continue to be an essential method to investigate the cell autonomous biology of cardiomyocytes within the healthy and disease heart. There's several questions we can answer using isolated cardiomyocytes.Such as the proliferative potential. There are gene expression changes or specific cytokine expressions upon injury response. Unfortunately, mouse cardiomyocytes do not survive past one week in normal culture conditions.Therefore, in this video, we describe an optimized method to isolate adult mouse cardiomyocytes, transfixed them and cultured them well beyond 21 days, this technique is initially hard to master. But with practice one can achieve about 80 to 90%survive in cardiomyocytes after isolation and about a 100 percent transfection efficiency. And most of these cardiomyocytes in correct conditions can survive past 20 days.Clean and sterilize your surgical instruments by soaking them in 70%alcohol for 15 minutes and subsequently washing them with double distilled water. After the water, leave the tools in the air to dry next, clean the profusion apparatus by running 70%alcohol twice for five minutes each. Increasing the flow rate will help to clean the tubing after alcohol rinse out any remaining alcohol by running double distilled water for 10 minutes.set up three dishes to clean the heart after excision. Fill each of the dishes with 20 milliliters of myocyte buffer. Add two to three drops of heparin to each dish with the Pasteur pipette and mix Well by pipetting up and down multiple times.Take a 10 milliliter syringe and fill it with myocyte buffer. Remove any of the air bubbles from the syringe and place it in the third dish in an angled position, securing it with tape. Prepare a loose Knot with surgical suture and place it around the needle.Inject the mouse with heparin through IP injection 20 minutes prior to anesthesia. Circulate the myocyte profusion buffer through the profusion apparatus at a flow rate of three milliliters per minute. After five minutes, replace the profusion buffer with enzyme solution, saturate the enzyme solution with oxygen during the process, again, set the enzyme solution to a flow rate of three mLs per minute.Confirm anesthesia by toe pinching and place the mouse on the surgical platform. Sterilize the skin with 70%alcohol. Carefully open the chest, exercise the heart and put the heart in the first dish.Clear the blood from the heart by gentle squeezing, then transfer the heart to the second dish to further clean the blood from the heart and to remove any non-cardiac tissues. Subsequently transfer the heart to the third dish. Find the aorta and use your forceps to keep it Peyton more placing it around the cannulating needle.Secure it by pulling down your pre tight knot tightening and then making a second knot. For additional stability fix the order and place with the help of a clip. Trim any excess suture thread, and finally start the heart profusion using the myocyte buffer in the syringe to clear any of the blood remaining in the heart.Carefully remove the calculating needle from the syringe and hook it to the profusion apparatus. Attempt to prevent any air bubbles from going into the heart. As this may affect the flow of the enzyme solution and digestion.Move the water jacket up, to provide a homogeneous environment to the heart during profusion. Allow the enzyme solution to flow through the heart with a speed of two to three mLs per minute. Let the enzyme solution flow through the heart for two minutes.At two minutes, mix in 40 microliters of a hundred micromolar calcium chloride solution to the enzyme solution. Let the enzyme solution pass through the heart for another 10 to 15 minutes. Once the flow becomes smooth and the heart starts to look brown and soft, you know that you have an even distribution of the collagenase enzyme to achieve proper digestion of the heart.When you think your digestion is complete, take the heart down from the Langendorff perfusion system and put it into a 16 millimeter Petri dish filled with five milliliters of enzyme solution and take it to a biosafety foot. Carefully remove the atria and extra fat tissue. Mince the heart in defined pieces with the help of forceps.Take a sterile Pasteur pipette and cut its tip at 45 degrees. Use the Pasteur pipette to break up the heart tissue by gentle pipetting up and down. Optimal digestion provides a suspension of single cell cardiomyocytes after that add five milliliters of stop solution to stop the enzyme activity to avoid over digestion, Take a first 50 milliliter conical tube and place a sterile a hundred micron cell strainer on it.Pass the cardiomyocyte suspension through the cell strainer to remove any large chunks of tissue. Finally wash the strainer with stop solution to collect any attached cardiomyocyte remains. Centrifuge the cell suspension at 20 GS for three minutes and discard the supernatant.Re suspend the cardiomyocytes and 10 milliliters of stop solution, at three minute intervals at 10 microliters of 100 millimolar calcium chloride solution four times and mix. After the fourth edition centrifuge the cardiomyocytes suspension at 20 GS for three minutes and discard the supernatant. Re suspend the cardiomyocytes into culture media Pre plate the cells into a 60 millimeter dish and put into CO2 incubator for two to three hours.In two to three hours. The main contaminant cell types like fiber blasts will be adhered to the service of the dish, allowing for pure isolation of cardiomyocytes. After that, take the dish out of the incubator and collect the floating cardiomyocytes in a conical tube and replayed the cardiomyocytes in a laminin coated 24 well culture plate.Four to six hours is sufficient for the cardiomyocytes to adhere to the surface. So transfection could be performed at six hours after plating. RNA IMAX transfection reagent was used to transplant cardiomyocytes with siRNAs.The culture media contains 25 micromolar blood Staten supplemented with 10%FBS, which we have found is better suited to perform longterm cardiomyocyte culture and induce proliferation analysis. After transfection, you can view the cardiomyocytes by microscopy utilizing a micro incubator to how's the cells for time-lapse imaging. These are brightfield images of transfected rod shaped cardiomyocytes at low and high magnification.Here, you can see day by day imaging, which showcases changes in adult mouse cardiomyocyte morphology. We confirm that the cardiomyocytes are healthy and contractile at early time points, as well as after D differentiation and longterm culture. Here's an example of Ki67 immunofluorescent staining demonstrating induced proliferation of adult cardiomyocytes in culture after siRNAs, a transfection.As you can see from the results using this technique, one can obtain healthy adult cardiomyocytes from mouse and rat and culture them for longterm study. In conclusion, once mastered this technique will allow us to study cardiomyocytes well beyond the current culturing protocols.

isolation-transfection-long-term-culture-adult-mouse-rat

Research

JoVE Journal

Biology

8.8K Views.  University of Cincinnati. The objective of this video is to demonstrate a standardized protocol for adult cardiomyocytes isolation, long-term culture and transfection. Isolating and culturing cardiomyocytes from mouse or rat continue to be an essential method to investigate the cell autonomous biology of cardiomyocytes within the healthy and disease heart. There's several questions we can answer using isolated cardiomyocytes.Such as the proliferative potential. There are gene expression changes or specific cyto...