Name: measuring the strength of mice
Uploaded: 2013-06-02T14:00:00
Duration: 6 min 17 s
Description: Watch this Scientific Journal Video about Measuring the Strength of Mice at JoVE.com

The Wellcome Trust for providing Open Access funding to Oxford University. Robert Deacon is a member of Oxford OXION group, funded by Wellcome Trust grant WT084655MA.

1. Apparatus
1.1 Kondziela's inverted screen test
The inverted screen is a 43 cm square of wire mesh consisting of 12 mm squares of 1 mm diameter wire (Figure 1). It is surrounded by a 4 cm deep wooden beading (which prevents the occasional mouse which attempts to from climbing on to the other side) (Figure 2).
1.2 Weights test
Seven weights constitute the apparatus. Each consists of a ball of tangled fine gauge stainless steel wire, a "scale collector" as used to prevent limestone scale formation in domestic kettles. The weight of this is small (7 g) but each scale collector is attached to a series of steel chain links, each weighing approximately 13 g. The number of links ranges from one to seven. Their weights are therefore: 20, 33, 46, 59, 72, 85 and 98 g (Figures 3 and 4).
2. Procedure
For all tests, bring the mice to the experimental room 5-20 min before testing to ensure they are properly awake. As a general rule, to allow recovery of muscular strength and a return to normal levels of arousal, rest the mice by a return to the home cage after each motor test.
<ol>
	<li>Kondziela's inverted screen test</li>
	<li>Procedure: Place the mouse in the center of the wire mesh screen, start a stopclock, rotate the screen to an inverted position over 2 sec, with the mouse's head declining first. Hold the screen steadily 40-50 cm above a padded surface. Note the time when the mouse falls off, or remove it when the criterion time of 60 sec is reached. Longer criterion times may be useful for some experiments.</li>
	<li>Scoring the inverted screen:</li>
</ol>
Falling between 1-10 sec = 1 
Falling between 11-25 sec = 2 
Falling between 26-60 sec = 3 
Falling after 60 sec = 4
Or, e.g. for 2 min: 
Falling between 1-10 sec = 1 
Falling between 11-25 sec = 2 
Falling between 26-60 sec = 3 
Falling between 61-90 sec = 4 
Falling after 90 sec = 5
3. Weights Test
Hold a mouse by the middle/base of the tail and lower it to allow it to grasp the first weight (20 g) which is lying on the laboratory bench. As it grasps the wire scale collector with its forepaws, start a stop clock and raise the mouse until the link is clear of the bench. A hold of three seconds is the criterion. If the mouse drops the weight in less than 3 sec, note the time it held the weight. Rest the mouse for about 10 sec and try it on the weight once again. If it fails three times, that terminates the trial, and the mouse is assigned the maximum time/weight achieved. If it holds it for 3 sec then try it on the next heaviest weight. If it lifts this for 3 sec, test it on the next heavier weight, after you have tested all its cagemates on the first weight. Again, it is given three chances to hold the weight for 3 sec. A final total score is calculated as the product of the number of links in the heaviest chain held for the full 3 sec, multiplied by the time (sec) it is held. If the heaviest weight is dropped before 3 sec an appropriate intermediate value is calculated. Thus a mouse holding a 5-link weight for 3 seconds, but unable to lift a 6-link weight, is assigned a score of (5 x 3) = 15. If it holds the 6-link weight for 1 second, it scores (5 x 3) + (1) =16.
Sometimes mice may not be adequately motivated to grip the apparatus. This generally occurs in older animals. This problem can be minimized by holding the mice by the tail for a longer time before bringing it within gripping distance of the wire ball.

<ol>
	<li>Bulfield, G., Siller, W. G., Wight, P. A., Moore, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=K.J.X+chromosome-linked+muscular+dystrophy+(mdx)+in+the+mouse.">K.J.X chromosome-linked muscular dystrophy (mdx) in the mouse.</a> Proc. Natl. Acad. Sci. U.S.A. 81, 1189-1192 (1984).</li><li>Contet, C., Rawlins, J. N. P., Deacon, R. M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+comparison+of+129S2/SvHsd+and+C57BL/6JOlaHsd+mice+on+a+test+battery+assessing+sensorimotor,+affective+and+cognitive+behaviours:+implications+for+the+study+of+genetically+modified+mice.">A comparison of 129S2/SvHsd and C57BL/6JOlaHsd mice on a test battery assessing sensorimotor, affective and cognitive behaviours: implications for the study of genetically modified mice.</a> Behavioural Brain Research. 124, 33-46 (2001).</li><li>Deacon, R. M. J., Brook, R. C., Meyer, D., Haeckel, O., Ashcroft, F. M., Miki, T., Seino, S., Liss, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Behavioral+phenotyping+of+mice+lacking+the+KATP+channel+subunit+Kir6.2.">Behavioral phenotyping of mice lacking the KATP channel subunit Kir6.2.</a> Physiol. Behav. 87, 723-733 (2006).</li><li>Deacon, R. M. J., Croucher, A., Rawlins, J. N. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hippocampal+cytotoxic+lesion+effects+on+species-typical+behaviors+in+mice.">Hippocampal cytotoxic lesion effects on species-typical behaviors in mice.</a> Behav. Brain Res. 132, 203-213 (2002).</li><li>Rawlins, J. N. P., Morley, B. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+comparison+of+the+behavior+of+C57BL/6+and+C57BL/10+mice.">A comparison of the behavior of C57BL/6 and C57BL/10 mice.</a> Behav. Brain Res. 179, 239-247 (2007).</li><li>Guenther, K., Deacon, R. M. J., Perry, V. H., Rawlins, J. N. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+behavioural+changes+in+scrapie-affected+mice+and+the+influence+of+dapsone.">Early behavioural changes in scrapie-affected mice and the influence of dapsone.</a> Eur. J. Neurosci. 14, 401-409 (2001).</li><li>Kondziela, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Eine+neue+method+zur+messung+der+muskularen+relaxation+bei+weissen+mausen.">Eine neue method zur messung der muskularen relaxation bei weissen mausen.</a> Arch. Int. Pharmacodyn. 152, 277-284 (1964).</li></ol>

No conflicts of interest declared.

Mouse models of the many diseases that affect the human motor systems are continually being developed, therefore good assays of strength in mice are essential. Examples include the many forms of muscular dystrophy, Parkinson's disease and Huntington's chorea. Strength assays also find use in models of nerve regeneration after spinal or peripheral nerve damage. Industrial and automobile accidents continue to cause considerable disability to humans, but much preclinical work is presently investigating possible avenues of treatment based on nerve growth factors.
Muscles never work individually. They are activated by the brain, local or higher spinal reflexes, via the neuromuscular junctions and work within the constraints of other muscles and the skeletal system. Therefore, the complexity of the system means in vivo assays of muscular force in the awake animal are essential in the evaluation of its present condition and the effects of any putative treatments. Mice instinctively hold on to materials with a strong grip, thus Mus musculus is an ideal model animal in which to assess disorders of muscular strength and possible treatments.

To a lay person, the idea of measuring strength in mice might appear absurd, even something of an oxymoron. However, it is not without reason that house/lab mice are named Mus musculus. They actually have a very high strength/weight ratio, greater than that of rats. For instance, adult mice can easily support their own body weight, even using only the fore or hind paws; very few adult lab rats can do this.
Mice are playing an ever greater role in biomedical research. They can be used to model many human motor disorders, both somatic and central nervous system in origin. The former include the more than thirty forms of inherited muscular dystrophy1 and myasthenia gravis, while examples of the latter are multiple sclerosis, spinal muscular atrophy, Parkinson's disease, Huntington's disease and amyotrophic lateral sclerosis. For all of these models, a full assessment of their motor deficits must include specific tests of strength.

measuring the strength of mice

Kondziela7 devised the inverted screen test and published it in 1964. It is a test of muscle strength using all four limbs. Most normal mice easily score maximum on this task; it is a quick but insensitive gross screen, and the weights test described in this article will provide a finer measure of muscular strength.
There are also several strain gauge-based pieces of apparatus available commercially that will provide more graded data than the inverted screen test, but their cost may put them beyond the reach of many laboratories which do not specialize in strength testing. Hence in 2000 a cheap and simple apparatus was devised by the author. It consists of a series of chain links of increasing length, attached to a "fur collector" a ball of fine wire mesh sold for preventing limescale build up in hard water areas. An accidental observation revealed that mice could grip these very tightly, so they proved ideal as a grip point for a weight-lifting apparatus. A common fault with commercial strength meters is that the bar or other grip feature is not thin enough for mice to exert a maximum grip. As a general rule, the thinner the wire or bar, the better a mouse can grip with its small claws.
This is a pure test of strength, although as for any test motivational factors could potentially play a role. The use of scale collectors, however, seems to minimize motivational problems as the motivation appears to be very high for most normal young adult mice.

Expected Results
Contet et al.2 demonstrated that 129S2/sv mice performed similarly on the weights test to C57BL/6 mice. Female C57BL/6 mice scored approximately 15, 129 mice 17, which means they could lift approximately 5 chain links, around 70 g. This is a high value; normally 2-3 chain links (score 6-9, 33-46 g) are lifted by C57BL/6 mice5. These differences are presumably related to factors such as how much handling the mice have received and the details of the experimenter's technique.
Hippocampal lesions did not affect strength as measured either by the weights test or the inverted screen4. Prion (scrapie) diseased mice were impaired on the inverted screen by 18 weeks after infection6. Although somewhat impaired on the horizontal bar and rotarod relative to C57BL/6 mice, C57BL/10 mice were not impaired on weightlifting5. Knockout mice for the KATP channel subunit Kir6.2 were not impaired on the inverted screen or weightlifting tests, although the females scored higher than males on the latter3. This was unusual; normally the heavier males display greater strength than the females.
<img alt="Figure 1" src="/files/ftp_upload/2610/2610fig1.jpg" /> 
 Figure 1. The inverted screen.
<img alt="Figure 2" src="/files/ftp_upload/2610/2610fig2.jpg" /> 
 Figure 2. Close view of a mouse on the inverted screen.
<img alt="Figure 3" src="/files/ftp_upload/2610/2610fig3.jpg" /> 
 Figure 3. Weights, ranging from 20 g to 98 g.
<img alt="Figure 4" src="/files/ftp_upload/2610/2610fig4.jpg" /> 
 Figure 4. A mouse weightlifting.

Watch this Scientific Journal Video about Measuring the Strength of Mice at JoVE.com

Measuring the Strength of Mice

Deficits in muscular strength occur in many clinical conditions such as motor neuron disease. The inverted screen and weight lifting tests described here measure strength in mice almost exclusively, with minimal influence of factors such as coordination.

Kondziela7 devised the inverted screen test and published it in 1964. It is a test of muscle strength using all four limbs. Most normal mice easily score ...

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Medicine

Transthoracic Echocardiography in Mice

In recent years, murine models have become the primary avenue for studying the molecular mechanisms of cardiac dysfunction resulting from changes in gene expression. Transgenic and gene targeting methods can be used to generate mice with altered cardiac size and function,1-3 and as a result, in vivo techniques are needed to evaluate their cardiac phenotype. Transthoracic echocardiography, pulse wave Doppler (PWD), and tissue Doppler imaging (TDI) can be used to provide dimensional measurements of the mouse heart and to quantify the degree of cardiac systolic and diastolic performance. Two-dimensional imaging is used to detect abnormal anatomy or movements of the left ventricle, whereas M-mode echo is used for quantification of cardiac dimensions and contractility.4,5 In addition, PWD is used to quantify localized velocity of turbulent flow,6 whereas TDI is used to measure the velocity of myocardial motion.7 Thus, transthoracic echocardiography offers a comprehensive method for the noninvasive evaluation of cardiac function in mice.

Transthoracic echocardiography offers a noninvasive method for the evaluation of cardiac function in mice. A combination of ultrasound and Doppler imaging modalities can be used to obtain dimensional measurements of the heart and intracardiac blood flow, which together provide an assessment of cardiac systolic and diastolic performance.

In recent years, murine models have become the primary avenue for studying the molecular mechanisms of cardiac dysfunction resulting from changes in gene ...

Manual Muscle Testing:  A Method of Measuring Extremity Muscle Strength Applied to Critically Ill Patients

Survivors of acute respiratory distress syndrome (ARDS) and other causes of critical illness often have generalized weakness, reduced exercise tolerance, and persistent nerve and muscle impairments after hospital discharge.1-6 Using an explicit protocol with a structured approach to training and quality assurance of research staff, manual muscle testing (MMT) is a highly reliable method for assessing strength, using a standardized clinical examination, for patients following ARDS, and can be completed with mechanically ventilated patients who can tolerate sitting upright in bed and are able to follow two-step commands. 7, 8 
This video demonstrates a protocol for MMT, which has been taught to &ge;43 research staff who have performed &gt;800 assessments on &gt;280 ARDS survivors. Modifications for the bedridden patient are included. Each muscle is tested with specific techniques for positioning, stabilization, resistance, and palpation for each score of the 6-point ordinal Medical Research Council scale.7,9-11 Three upper and three lower extremity muscles are graded in this protocol: shoulder abduction, elbow flexion, wrist extension, hip flexion, knee extension, and ankle dorsiflexion. These muscles were chosen based on the standard approach for evaluating patients for ICU-acquired weakness used in prior publications. 1,2.

Survivors of acute respiratory distress syndrome (ARDS) and critical illness frequently develop long-lasting muscle weakness. Manual muscle testing (MMT) is a standardized clinical examination commonly used to measure strength of peripheral skeletal muscle groups. This video demonstrates MMT using the 6-point Medical Research Council scale.

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Orthotopic Aortic Transplantation in Mice for the Study of Vascular Disease

Vascular procedures involving anastomoses in the mouse are generally thought to be difficult and highly dependent on the skill of the individual surgeon. This is largely true, but there are a number of important principles that can reduce the difficulty of these procedures and enhance reproducibility. Orthotopic aortic transplantation is an excellent procedure in which to learn these principles because it involves only two end-to-end anastomoses, but requires good suturing technique and handling of the vessels for consistent success. This procedure begins with the procurement of a length of abdominal aorta from a donor animal, followed by division of the native aorta in the recipient. The procured aorta is then placed between the divided ends of the recipient aorta and sutured into place using end-to-end anastomoses. To accomplish this objective successfully requires a high degree of concentration, good tools, a steady hand, and an appreciation of how easily the vasculature of a mouse can be damaged, resulting in thrombosis. Learning these important principles is what occupies most of the beginner's time when learning microsurgery in small rodents. Throughout this protocol, we refer to these important points. This model can be used to study vascular disease in a variety of different experimental systems1-8. In the context shown here, it is most often used for the study of post-transplant vascular disease, a common long-term complication of solid organ transplantation in which intimal hyperplasia occurs within the allograft. The primary advantage of the model is that it facilitates quantitative morphometric analyses and the transplanted vessel lies contiguous to the endogenous vessel, which can serve as an additional control9. The technique shown here is most often used for mice weighing 18-25 grams. We have accumulated most of our experience using the C57BL/6J, BALB/cJ, and C3H/HeJ strains.

We describe a technique in which a section of the abdominal aorta from a mouse is transplanted orthotopically to just below the renal arteries in an allogeneic or syngeneic recipient. This technique can be useful in studies in which transplantation of large arteries of uniform size is deemed advantageous.

Vascular procedures involving anastomoses in the mouse are generally thought to be difficult and highly dependent on the skill of the individual surgeon. ...

Measuring Ascending Aortic Stiffness In Vivo in Mice Using Ultrasound

We present a protocol for measuring in vivo aortic stiffness in mice using high-resolution ultrasound imaging. Aortic diameter is measured by ultrasound and aortic blood pressure is measured invasively with a solid-state pressure catheter. Blood pressure is raised then lowered incrementally by intravenous infusion of vasoactive drugs phenylephrine and sodium nitroprusside. Aortic diameter is measured for each pressure step to characterize the pressure-diameter relationship of the ascending aorta. Stiffness indices derived from the pressure-diameter relationship can be calculated from the data collected. Calculation of arterial compliance is described in this protocol.
This technique can be used to investigate mechanisms underlying increased aortic stiffness associated with cardiovascular disease and aging. The technique produces a physiologically relevant measure of stiffness compared to ex vivo approaches because physiological influences on aortic stiffness are incorporated in the measurement. The primary limitation of this technique is the measurement error introduced from the movement of the aorta during the cardiac cycle. This motion can be compensated by adjusting the location of the probe with the aortic movement as well as making multiple measurements of the aortic pressure-diameter relationship and expanding the experimental group size.

Measuring Ascending Aortic Stiffness In Vivo in Mice Using Ultrasound

We describe a technique for measuring aortic stiffness from its pressure-diameter relationship in vivo in mice. Aortic diameter is recorded by ultrasound and aortic pressure is measured invasively with a solid-state pressure catheter. Blood pressure is changed incrementally and the resulting diameter is measured.

We present a protocol for measuring in vivo aortic stiffness in mice using high-resolution ultrasound imaging. Aortic diameter is measured by ultrasound ...

Adapted Resistance Training Improves Strength in Eight Weeks in Individuals with Multiple Sclerosis

Hip weakness is a common symptom affecting walking ability in people with multiple sclerosis (MS). It is known that resistance strength training (RST) can improve strength in individuals with MS, however; it remains unclear the duration of RST that is needed to make strength gains and how to adapt hip strengthening exercises for individuals of varying strength using only resistance bands. This paper describes the methodology to set up and implement an adapted resistance strength training program, using resistance bands, for individuals with MS. Directions for pre- and post-strength tests to evaluate efficacy of the strength-training program are included. Safety features and detailed instructions outline the weekly program content and progression. Current evidence is presented showing that significant strength gains can be made within 8 weeks of starting a RST program. Evidence is also presented showing that resistance strength training can be successfully adapted for individuals with MS of varying strength with little equipment.

Hip weakness is a common symptom affecting walking ability in people with multiple sclerosis. Isolated muscle strengthening is a useful method to target specific weaknesses. This protocol describes a progressive resistance-training program using exercise bands to increase hip muscle strength.

Hip weakness is a common symptom affecting walking ability in people with multiple sclerosis (MS). It is known that resistance strength training (RST) can ...

Improving Strength, Power, Muscle Aerobic Capacity, and Glucose Tolerance through Short-term Progressive Strength Training Among Elderly People

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The effect of short-term resistance training on elderly people was investigated through the simultaneous use of several methods. Compared to a control group, many improvements were seen, including on muscle aerobic capacity, glucose tolerance, strength, power, and muscle quality (i.e., protein involved in cell signaling and muscle fiber type composition).

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Measuring the Effect of Chemicals on the Growth and Reproduction of Caenorhabditis elegans

Toxicological evaluation is crucial for understanding the effects of chemicals on living organisms in basic and applied biological science fields. A non-mammalian soil round worm, Caenorhabditis elegans, is a valuable model organism for toxicology studies due to its convenience and lack of animal ethics issues compared with mammalian animal systems. In this protocol, a detailed procedure of toxicological evaluation of chemicals in C. elegans is described. A clinical anticancer drug, etoposide, which targets human topoisomerase II and inhibits DNA replication of human cancer cells, was selected as a model testing chemical. Age-synchronized C. elegans eggs were exposed to either dimethyl sulfoxide (DMSO) or etoposide, and then the growth of C. elegans was monitored every day for 4 days by the stereo microscope observation. The total number of eggs laid from C. elegans treated with DMSO or etoposide was also counted by using the stereo microscope. Etoposide treatment significantly affected the growth and reproduction of C. elegans. By comparison of the total number of eggs laid from worms with different treatment periods of chemicals, it can be decided that the reproductive toxicity of chemicals on C. elegans reproduction is reversible or irreversible. These protocols may be helpful for both the development of various drugs and risk assessment of environmental toxicants.

Measuring the Effect of Chemicals on the Growth and Reproduction of Caenorhabditis elegans

A basic protocol to evaluate the toxicity of chemicals in a model animal, Caenorhabditis elegans, is described. The method is convenient and useful for the development of pharmaceuticals as well as for the risk assessment of various environmental pollutants.

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The literature describes several methods for mouse intubation that either require visualization of the glottis through the oral cavity or incision in the ventral neck for direct confirmation of cannula placement in the trachea. The relative difficulty or the tissue trauma induced to the subject by such procedures can be an impediment to an investigator&#8217;s ability to perform longitudinal studies. This article illustrates a technique in which physical manipulation of the mouse following the use of a depilatory to remove hair from the ventral neck permits transcutaneous visualization of the trachea for orotracheal intubation regardless of degree of skin pigmentation. This method is innocuous to the subject and easily achieved with a limited understanding of murine anatomy. This refined approach facilitates repeated intubation, which may be necessary for monitoring progression of disease or instillation of treatments. Using this method may result in a reduction of the number of animals and technical skill required to measure lung function in mouse models of respiratory disease.

The goal of this article is to describe a refined method of intubation of the laboratory mouse. The method is noninvasive and, therefore, ideal for studies that require serial monitoring of respiratory function and/or instillation of treatments into the lung.

The literature describes several methods for mouse intubation that either require visualization of the glottis through the oral cavity or incision in the ...

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Here, we present a &#8220;Q&#8221; suture technique that can be performed in tendon repair and its effects on the gap formation and tensile strength of the repaired tendons. Q suture is shown to be efficient in enhancing the tensile resistance and tendon repair strength.

Peripheral epitendinous sutures are believed to enhance core suture strength in tendon repair and decrease the risk of gapping between tendon ends. Here Q ...