A subscription to JoVE is required to view this content. Sign in or start your free trial.
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. 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.
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.
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)
2. Extraction of heart from adult mice (and rats)
3. Digestion of the heart
4. Preparation of CM single-cell suspension
5. Removal of non-CMs
6. Adult CM plating
7. Transfection
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 (
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<...
None.
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. 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).
Name | Company | Catalog Number | Comments |
2,3-Butane Dione monoxime | Sigma-Aldrich | B-0753 | |
Blebbistatin | APExBIO | B1387 | |
Bovine serum albumin | Sigma-Aldrich | A3059 | |
CaCl2 | Sigma-Aldrich | 449709 | |
Cell culture plate | Corning Costar | 3526 | |
Cell strainer | BD Biosciences | 352360 | |
Cel-miR-67 | Dharmacon | CN-001000-01-50 | |
Collagenase type2 | Worthington | LS004177 | |
Disposable Graduated Transfer Pipettes | Fisherbrand | 13-711-20 | |
Disposable polystyrene weighing dishes | Sigma-Aldrich | Z154881-500EA | |
Dulbecco's Modified Eagle's medium | Thermo Scientific | SH30022.01 | |
EdU | Life Technologies | C10337 | |
Fetal bovine serum | Corning | 35-015-CV | |
Fine Point High Precision Forceps | Fisherbrand | 22-327379 | |
Glucose | Sigma-Aldrich | G-5400 | |
Hemocytometer | Hausser Scientific | 1483 | |
Heparin | Sagent Pharmaceuticals | PSLAB-018285-02 | |
HEPES | Sigma-Aldrich | H3375 | |
High Precision Straight Broad Strong Point Tweezers/Forceps | Fisherbrand | 12-000-128 | |
Hyaluronidase | Sigma | H3506 | |
Insulin | Sigma-Aldrich | I0516-5ML | |
K2HPO4 | Sigma-Aldrich | P-8281 | |
KCl | Sigma-Aldrich | 746436 | |
Light Microscope | Nikon | ||
Lipofectamine RNAiMAX | Life Technologies | 13778-150 | |
MgSO4 | Sigma-Aldrich | M-2643 | |
NaCl | Sigma-Aldrich | S9888 | |
NaOH | Fisher Scientific | S318-500 | |
Natural Mouse Laminin | Invitrogen | 23017-015 | |
Penicillin/Streptomycin | Corning | 30-002-CI | |
Pentobarbital | Henry Schein | 24352 | |
Phosphate buffered saline | Life Technologies | 20012-027 | |
Protease XIV | Sigma-Aldrich | P5147-1G | |
Selenium | Sigma-Aldrich | 229865+5G | |
siMeis2 | Dharmacon | s161030 | |
siRb1 | Dharmacon | s128325 | |
Straight Blunt/SharpDissecting Scissors | Fisher Scientific | 28252 | |
Straight Very Fine Precision Tip Forceps | Fisherbrand | 16-100-120 | |
Taurine | Sigma-Aldrich | T0625 | |
Transferrin | Sigma-Aldrich | T8158-100MG | |
Ultra-smooth, beveled-edge finish scissor | Fisherbrand | 22-079-747 | |
Water Bath | Fisher Scientific | 3006S |
Request permission to reuse the text or figures of this JoVE article
Request PermissionExplore More Articles
This article has been published
Video Coming Soon
Copyright © 2025 MyJoVE Corporation. All rights reserved
We use cookies to enhance your experience on our website.
By continuing to use our website or clicking “Continue”, you are agreeing to accept our cookies.