The present protocol describes a unique technique called dosage-adjusted resistance training (DART), which can be incorporated into precision rehabilitation studies performed in small animals, such as mice.
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Method Article
Dosage-Adjusted Resistance Training in Mice with a Reduced Risk of Muscle Damage
In This Article
Summary
Abstract
Progressive resistance training (PRT), which involves performing muscle contractions against progressively greater external loads, can increase muscle mass and strength in healthy individuals and in patient populations. There is a need for precision rehabilitation tools to test the safety and effectiveness of PRT to maintain and/or restore muscle mass and strength in preclinical studies on small and large animal models. The PRT methodology and device described in this article can be used to perform dosage-adjusted resistance training (DART). The DART device can be used as a standalone dynamometer to objectively assess the concentric contractile torque generated by the ankle dorsiflexors in mice or can be added to a pre-existing isokinetic dynamometry system. The DART device can be fabricated with a standard 3D printer based on the instructions and open-source 3D print files provided in this work. The article also describes the workflow for a study to compare contraction-induced muscle damage caused by a single bout of DART to muscle damage caused by a comparable bout of isometric contractions (ISOM) in a mouse model of limb-girdle muscular dystrophy type 2B/R2 (BLAJ mice). The data from eight BLAJ mice (four animals for each condition) suggest that less than 10% of the tibialis anterior (TA) muscle was damaged from a single bout of DART or ISOM, with DART being less damaging than ISOM.
Introduction
Exercise confers numerous health benefits on skeletal muscle (reviewed in Vina et al.1). Specifically, progressive resistance training (PRT), which involves performing muscle contractions against progressively greater external loads (e.g., barbells, dumbbells, cable-pulley-weight circuits), is known to help increase muscle mass and strength in both healthy individuals and patient populations (reviewed in previous publications2,3). PRT is based on the overload principle, which states that, when the muscle contracts against progressively greater external loads, it adapts by increasing its....
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Protocol
The experiments described in this article were approved by the Institutional Animal Care and Use Committee (IACUC) at Wayne State University, Detroit, Michigan, USA, in accordance with the Guide for the Care and Use of Laboratory Animals (1996, published by National Academy Press, 2101 Constitution Ave. NW, Washington, DC 20055, USA). B6.A-Dysfprmd/GeneJ mice (a.k.a. BLAJ mice, males, ~1.5 years old) that model LGMD2B/R2 were used for the present study. The mice were obtained from a commercial source (see Table of Materials).
1. Study design
- Choose mouse strain(s) relevant to....
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Results
BLAJ male mice, which were ~1.5 years in age, were studied. BLAJ mice model the human muscle disease, LGMD2B/R2. These mice are particularly susceptible to delayed onset muscle damage from a single bout of eccentric muscle contractions22,29. BLAJ mice were, therefore, chosen for these studies to learn if DART could be performed in a non-injurious manner by precisely adjusting the resistance against which the TA muscle has to work in a concentrically biased manner.......
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Discussion
This article presents step-by-step instructions on how to construct a device to perform a type of precision rehabilitation training called dosage-adjusted resistance training (DART). The work also describes the application of the DART device and methodology in a training study to compare muscle damage 3 days after a single bout of DART (DART group) with damage 3 days after a comparable bout of isometric training (ISOM group).
The critical steps in the protocol are the proper construction of th.......
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Disclosures
The authors have no competing financial interests.
Acknowledgements
This study was funded by grants from the Jain Foundation Inc., R03HD091648 from NICHD, a Pilot Grant from AR3T under NIH P2CHD086843, a FRAP Award from EACPHS at Wayne State University, a Faculty Startup Package from Wayne State University, and a subcontract from 1R01AR079884-01 (Peter L. Jones PI) to JAR. This study was also funded by an American Physical Therapy Association - Michigan (APTA-MI) research grant to JMB, MEP, and JAR. The authors acknowledge Dr. Renuka Roche (Associate Professor, Eastern Michigan University, MI) for critically reading the manuscript and providing feedback. The authors acknowledge Mr. Anselm D. Motha for advice on 3D printing.....
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Materials
| Name | Company | Catalog Number | Comments |
|---|---|---|---|
| AnMiao Star 608 Ceramic Ball Bearing | Anmiao Star (N/A) | AMS127 | High precision, low friction wheel bearing. If make and model is not commercially available, an alternative version of a 608 low-friction wheel bearing, 8 mm bore diameter, 22 mm outside diameter, with silicon nitride ceramic balls in 420 stainless steel housing should suffice. Excess friction in the wheel bearing will adversely impact performance of the DART device and will increase overall resistance to muscle contractions. |
| Axio Scope.A1 microscope | Carl Zeiss (Peabody, MA) | Product #Axio Scope.A1 | Light and fluorescence microscope |
| B6.A-Dysfprmd/GeneJ (a.k.a. BLAJ mice) | The Jackson Laboratory (Bar Harbor, ME). Special colony maintained by The Jain Foundation Inc. for collaborators who study dysferlin. | Stock #012767 | Dysferlin deficient mice that model human limb girdle muscular dystrophy type 2B/R2. |
| Bipolar, transcutaneous, neuromuscular electrical stimulation (NMES) electrode | Harvard Apparatus, Holliston, MA | BS4 50–6824 | Electrode for NMES. If this electrode is not commercially available, please contact corresponding author for alternatives. |
| Coplin Staining Dish | ThermoFisher (Waltham, MA) | Catalog No. S17495 | Staining dish/jar for hematoxylin and eosin (H&E) staining of sections |
| Cura 4.4.1. Software | Ultimaker, Utrecht, Netherlands | Ultimaker Cura 4.4.1. | Slicing software to convert stereolithography files into G-CODE files |
| Deltaphase isothermal gel heating pad | Braintree Scientific (Braintree, MA) | Item #39DP | Heating pad to provide thermal support to animals while under anesthesia |
| Eosin Y | Millipore Sigma (Burlington, MA) | HT110132-1L | Pink cytoplasmic stain |
| Gorilla Super Glue | The Gorilla Glue Company (Cincinnati, OH) | Gorilla Super Glue Micro Precise | Cyanoacrylate adhesive to bond PLA components |
| Hematoxylin solution, Gill No.3 | Millipore Sigma (Burlington, MA) | GHS332-1L | Dark blue stain for nuclei |
| HM525NX cryostat | ThermoFisher (Waltham, MA) | Catalog #HM525NX | Cryostat to make frozen sections of muscle |
| Lab Wipes. Kimberly-Clark Professional Kimtech Science Kimwipes Delicate Task Wipers, 1-Ply | ThermoFisher (Waltham, MA) | Catalog No. 06-666. Manufacturer #34120 | Laboratory wipes to blot mineral oil from muscle tissue before snap freezing and for other purposes. |
| Labview 2014 | National Instruments, Austin, Texas, USA | Labview 2014 | Software for custom-written programs/routines that operate the dynamometer and trigger the NMES stimulator. |
| Liquid nitrogen HDPE Dewar Flasks | ThermoFisher (Waltham, MA) | S34074B. Thermo Scientific 41502000/EMD | Flask to hold liquid nitrogen for snap freezing muscle or other tissue |
| Magic depilatory cream | Softsheen Carson (New York, NY) | N/A | Razorless hair removal cream |
| Metal alligator clip | JINSHANGTOPK (web-based business) | 24Pcs 51mm Metal Alligator Clip Spring Clamps | Spring clamp to hold tibial pin |
| Micrscope slides | Globe Scientific (Mahwah, NJ) | 1354W. Diamond White Glass Slides | Charged microscope slides |
| Mineral Oil | ThermoFisher (Waltham, MA) | BP26291 | Mineral oil to cryoprotect muscle tissue before snap freezing |
| Monoprice Premium 3D Printer Filament PLA | Monoprice (Rancho Cucamonga, CA) | #11778 | Premium 3D Printer Filament PLA 1.75mm 1 kg/spool, Gray. This is the material used to 3D print device components. |
| Monoprice Select Mini V2 3D printer | Monoprice (Rancho Cucamonga, CA) | Mini V2 3D | 3D printer for computer-aided fabrication of device components. |
| NIH Image software | National Instritues of Health (NIH, Bethesda, MD) | NIH Image for Windows | Image processing and analysis software used to quantify area of muscle damage. NIH Image is also known as Image J. |
| Photoshop CS4 | Adobe (San Jose, CA) | Creative Suite (CS4). 64 bit version for Windows | Image processing and analysis software used to generate tiled/stiched images of entire muscle cross-section from images of indvidual overlapping fields |
| PSIU6 stimulation isolation unit | Grass Instruments (West Warwick, RI) | PSIU6 isolation unit | Isolation unit for NMES. Stimulators, such as Model 4100 from A-M come with a built in stimulation isoloation unit |
| Roboz 4-0 silk black braided suture material | Roboz Surgical (Gaithersburg, MD) | Roboz Surgical SUT152 | Suture material to connect DART device footplate to dynamometer footplate or resistance for resistance training |
| S48 square pulse stimulator | Grass Instruments (West Warwick, RI) | S48 Stimulator | Laboratory electrical stimulator for NMES . If this stimulator is not commercially available, Model 4100 Isolated High Power Stimulator from A-M systems could be an alternative. Please contact co-author Jones for more information. |
| Scott’s bluing reagent | Ricca Chemical Company (Arlington, TX) | 6697-32 | Bluing solution that intensifies hematoxylin nuclear staining |
| SigmaStat version 3.5 | Systat Software (San Jose, CA) | SigmaStat version 3.5 | Statistical software package for statistical analyses |
| Tabletop isoflurane vaporizer | VetEquip (Livermore, CA) | Item #901801 | Inhaled tabletop anesthesia system |
| Triple antibiotic first aid ointment | Global Health Products (wed-based business) | Globe Triple Antibiotic First Aid Ointment, 1 oz (2-Pack) First Aid Antibiotic Ointment | Antibiotic ointment applied on tibial pin as part of post-procedural care |
References
- Vina, J., Sanchis-Gomar, F., Martinez-Bello, V., Gomez-Cabrera, M. C. Exercise acts as a drug; The pharmacological benefits of exercise. British Journal of Pharmacology. 167 (1), 1-12 (2012).
- Murton, A. J., Greenhaff, P. L.
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