We thank Mr. John Crowell and Mr. Terry Upshall for their technical expertise and assistance with the photography and videography. This work was supported by operating grants to JLV from the Canadian Institutes of Health Research and the Research and Development Corporation of Newfoundland and a Heart &#38; Stroke Foundation of Canada Canadian Partnership for Stroke Recovery Catalyst grant. RBR was a recipient of a Keith Griffiths Memorial Heart &#38; Stroke Foundation Graduate Scholarship.

Ethics statement: All experiments were approved by Memorial University of Newfoundland&#39;s Animal Care Ethics Committee according to the guidelines of the Canadian Council on Animal Care.
1. Mice
<ol>
	<li>Use adult mice. In this study, adult male FVBN mice (n=10) between 2-4 months were used. House mice on a 12:12 hr reverse light-dark cycle and provide standard rodent chow and water ad libitum.</li>
</ol>
2. Materials Required for the Cylinder Test
<ol>
	<li>Obtain a table with a transparent top to film the cylinder test. The dimensions of the table are irrelevant, the top must be plexiglass or glass, and there must be enough room to position a mirror below the table. This allows for the mouse to be videotaped from below. Use a mirror below the table to reflect the image through the cylinder. As an alternative, use an upside-down camera if available. The dimensions of the table used in this protocol are 54 x 56 x 66.5cm (w x l x h) with a 51 x 51cm top (w x l).</li>
	<li>Obtain a mirror. The dimensions of the mirror used in this protocol are 34 x 58cm (w x l).</li>
	<li>Obtain a transparent/plexiglass cylinder for the mouse to perform in. The dimensions of the cylinder used in this protocol are 17.5cm high, 8.8cm I.D, 9.5cm O.D with a wall thickness of 0.35cm. A taller cylinder may be required for more active mouse strains.</li>
	<li>Place the cylinder on the tabletop and film the reflection in the mirror below.</li>
	<li>A videocamera and tripod are required. Record videos at approximately 650Kb/s, which is approximately 190Mb per 5 min of cylinder video. Ensure that the camera has a zoom functionality to ensure that the cylinder encompasses the entire field of view. 
	NOTE: The videocamera used in this protocol is a Sony DCR-SR42, 40x optical zoom, 2,000x digital zoom, 680kpix which uses standard definition, NTSC interlaced video.)</li>
	<li>Obtain software for analysis &#8211; a media player with video support and playback speed modulation. The media player used in this protocol is the VLC Media Player v2.1.2.</li>
	<li>Obtain a computer with an operating system capable of running the media player and a monitor.</li>
	<li>Electronic storage for videos is required. Download videos to an external hard drive or copy it onto DVDs for long-term storage. 
	NOTE: At 190Mb per video, 84 sessions will fit on a 16 GB SD card and 168 sessions will fit on a 32GB SD card. Due to the relative inexpensiveness of SD media, and the uncertainty in how much time some mice require to complete 20 rears, a 32 GB card is recommended. In the current study, the videos were copied from the camera to a 2TB external hard drive and then recopied onto DVDs as backup.</li>
</ol>
3. Experimental Setup of the Cylinder Test
<ol>
	<li>Fasten mirror below the table at a 45 degree angle to the tabletop. Do this using two support brackets attached to the table legs to support the top and bottom of the mirror, respectively. Bracket locations are noted in a side-view of the table (Figure 1A) and a face-on view of the table (Figure 1B).</li>
	<li>Place cylinder on the center of the table. Draw four equidistant lines where the cylinder sits on the table with a black marker (Sharpie) so that the cylinder can be lifted and returned to the same position (Figure 2). Drawing them on the underside of the transparent tabletop allows the tabletop to be cleaned between animal tests without dissolving the marker ink.</li>
	<li>Attach the camera and tripod. Aim the camera at the mirror so that the picture is looking directly through the barrel of the cylinder. Ensure that the full inner wall of the cylinder is visible and unobstructed by the base (Figure 3). See a side-on view of the setup, including the relative angle of the camera and mirror setup, from above (Figure 4A) and from the level of the table, including a mouse rearing (Figure 4B).</li>
	<li>Prepare cue cards to identify each mouse prior to filming. Ensure that the cards typically include an identification number for each mouse, the time-point of the test (e.g., 3 days after treatment) and the date of the filming session. Do not include the treatment group on the cue card to ensure the experimenter is blinded.</li>
	<li>Film in standard indoor lighting conditions as this level of light is required to clearly see the mouse movements around the cylinder. 
	NOTE: If available filming in the dark with a red light camera may suffice, however one would first need to test whether paw touches and drags are clearly visible for quantification.</li>
</ol>
4. Execution
<ol>
	<li>Start filming. Display the appropriate mouse cue card in front of camera lens.</li>
	<li>Lower the mouse into the cylinder from the open top immediately after filming the cue card.</li>
	<li>Begin filming the mouse. Minimize noise during this time, as mice may lose interest in exploring if startled.</li>
	<li>Observe the mice rear to explore the cylinder. Capture the video until the mouse performs a minimum of twenty rears. 
	NOTE: A rear occurs when both forepaws lose contact with the floor and the mouse stands on its hind legs.</li>
	<li>Wipe tabletop and cylinder with an appropriate cleaning solution between each mouse to sanitize and remove mouse scents.</li>
	<li>Freezing is when mice stop exploring and remain quietly sitting on all fours for approximately 5 min. If mice freeze before twenty rears occur, it may be necessary to remove them from the cylinder for 10-20 min before resuming the test. If mice do not perform twenty rears, they are removed from the study. 
	NOTE: In our experience, mice have never needed to be excluded due to failure to explore the cylinder.</li>
</ol>
5. Evaluation of the Cylinder Test using Paw-Dragging Analysis
<ol>
	<li>Play back the video at a rate of between 0.25x and 0.67x regular speed depending on how quickly the mouse explores the cylinder. Use a media player that offers slower playback speeds.</li>
	<li>Quantify the total number of paw touches. Paw touches occur when the mouse rears (Figure 5A), touches the side of the cylinder (Figure 5B), subsequently dismounts with both paws simultaneously (Figure 5C) and lands (Figure 5D). The paw may or may not contact the cylinder wall with a full palm, but some contact with the cylinder wall must occur. Assess paw touches by counting the number of times the mouse makes contact (no matter how brief) with the cylinder wall with either or both forepaws while standing on its hind limbs during a rear. 
	Note that contact with the cylinder wall is only counted as a &#8220;paw touch&#8221; or &#8220;paw-drag&#8221; if the mouse is in a rear position &#8211; standing on its hind limbs with both forepaws off of the tabletop. If the mouse remains in a 3-point stance &#8211; both hind limbs and one forepaw on the tabletop and proceeds to touch the wall with the free paw &#8211; this is not counted as a paw touch. Mice may rear and touch the cylinder wall with a single forepaw and this is counted as a paw touch. Note: a mouse may also move its body around the cylinder during a rear, making more than two contacts. These contacts are tallied &#8211; one for each left forepaw touch and one for each right forepaw touch.</li>
	<li>Quantify the number of paw-drags. Paw-dragging behaviour is distinct from normal paw touches.
	<ol>
		<li>If the paw contacts the cylinder wall with a full open palm (Figure 6B), it will slowly fall away from the wall, often with a slight tremor. The movement begins with the digits dragging against the cylinder wall either in a medial or downward direction, (Figure 6C) before falling away completely (Figure 6D). The mouse will then dismount with its unaffected paw (Figure 6E) before landing on all fours (Figure 6F). This is considered a paw-drag and should be counted in a tally.</li>
		<li>If the paw does not contact the cylinder wall with a fully open palm, it will graze the cylinder wall with its digits before falling away from the cylinder wall. Similarly, a mouse may drag its paw against the cylinder wall but not release it entirely before dismounting. These are both considered paw-drags as well as touches and should be counted as both in a tally.</li>
		<li>The paw may also drag along the cylinder wall while a mouse explores the cylinder. In this case, the paw will follow the twisting of the mouse&#8217;s torso as it explores left or right of its original position (Figure 7A-D) before dismounting (Figure 7E). This is not considered a paw-drag, as it depends on the mouse randomly choosing a direction to explore and does not depend on which cortical hemisphere was damaged.</li>
	</ol>
	</li>
	<li>Paw-drags are expressed as a percentage of paw-drags per total number of paw touches during a session. Express the number of paw-drags as a percentage of total paw contacts for each forelimb separately.</li>
	<li>Touches resulting in a paw-drag count as a paw-drag and a touch simultaneously. Thus, if a mouse drags its paw each time its paw contacts the cylinder wall, the paw-dragging percentage is expressed as 100%.</li>
</ol>
6. Additional Experimental Design Suggestions
<ol>
	<li>To minimize extraneous variables:
	<ol>
		<li>Test the mice at the same time on each testing day. Test the mice during their wake cycle. Keeping mice on a 12 hr reverse light cycle facilitates performance.</li>
		<li>Mice may be reluctant to explore the cylinder if stressed either by noise or a novel environment. Testing mice in their animal holding room or a room they have been familiarized with reduces stress. This can occur if the room is noisy, if the mouse has been jostled prior to entering the cylinder or due to habituation. 
		NOTE: Testing should be performed once before experimental manipulation to serve as a baseline reading. After manipulation, testing days are at the experimenter&#8217;s discretion, though it is advised to avoid an excessive number of exposures to the cylinder over a short period of time.</li>
		<li>Mice may become reluctant to rear after 6-7 exposures to the cylinder. For the current study, mice were tested in the cylinder for a total of seven times, prior to ischemia and on days 1, 3, 7, 14, 21 and 28 post-surgery. 
		NOTE: In this study we used the FVBN mouse strain. We have previously tested C57Bl/6 mice in the cylinder and observed paw-dragging behaviour following an ET-1 ischemic injury (data not shown). C57BL/6 mice were more active than FVBN mice when rearing and frequently jumped onto the rim of the cylinder before climbing out. Taller cylinders should be used if mice attempt to escape by jumping.</li>
	</ol>
	</li>
</ol>
7. Endothelin-1 Surgery and Infarct Volume Measurements
<ol>
	<li>Perform Endothelin-1 surgery and infarct volume measurements according to previously published protocols4 . To target the anterior forelimb motor cortex, each mouse should receive three ET-1 injections at the following coordinates: (i) +0.7 anteriorposterior (AP)/1.5 medial-lateral (ml)/-1.2 dorsal-ventral (DV), (ii) +0.4 AP/1.25 ml/- 1.2 DV and (iii) +0.1 AP/1.75 ml/-1.2 DV4 .</li>
</ol>
8. Statistical Analysis
<ol>
	<li>A two-way repeated measures analysis of variance (ANOVA) is recommended to analyze the percent of paw-dragging for the affected and unaffected paws across different time points.</li>
</ol>

<ol><li>Schallert, T., Fleming, S. M., Leasure, J. L., Tillerson, J. L., Bland, S. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((CNS+plasticity+and+assessment+of+forelimb+sensorimotor+outcome+in+unilateral+rat+models+of+stroke%2C+cortical+ablation%2C+parkinsonism+and+spinal+cord+injury%5BTitle%5D)+AND+%22Neuropharmacology%22%5BJournal%5D)">CNS plasticity and assessment of forelimb sensorimotor outcome in unilateral rat models of stroke, cortical ablation, parkinsonism and spinal cord injury.</a> Neuropharmacology. 39, 777-787 (2000).</li>
<li>Kolb, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Growth+factor-stimulated+generation+of+new+cortical+tissue+and+functional+recovery+after+stroke+damage+to+the+motor+cortex+of+rats%5BTitle%5D)+AND+%22J+Cereb+Blood+Flow+Metab%22%5BJournal%5D)">Growth factor-stimulated generation of new cortical tissue and functional recovery after stroke damage to the motor cortex of rats.</a> J Cereb Blood Flow Metab. 27 (5), 983-997 (2007).</li>
<li>Windle, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((An+analysis+of+four+different+methods+of+producing+focal+cerebral+ischemia+with+endothelin-1+in+the+rat%5BTitle%5D)+AND+%22Exp+Neurol%22%5BJournal%5D)">An analysis of four different methods of producing focal cerebral ischemia with endothelin-1 in the rat.</a> Exp Neurol. 201 (2), 324-334 (2006).</li>
<li>Roome, R. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+reproducible+Endothelin-1+model+of+forelimb+motor+cortex+stroke+in+the+mouse%5BTitle%5D)+AND+%22J+Neurosci+Methods%22%5BJournal%5D)">A reproducible Endothelin-1 model of forelimb motor cortex stroke in the mouse.</a> J Neurosci Methods. 233, 34-44 (2014).</li>
<li>Tennant, K. A., Jones, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Sensorimotor+behavioral+effects+of+endothelin-1+induced+small+cortical+infarcts+in+C57BL%2F6+mice%5BTitle%5D)+AND+%22J+Neurosci+Methods%22%5BJournal%5D)">Sensorimotor behavioral effects of endothelin-1 induced small cortical infarcts in C57BL/6 mice.</a> J Neurosci Methods. 181 (1), 18-26 (2009).</li>
<li>Wang, Y., Jin, K., Greenberg, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Neurogenesis+associated+with+endothelin-induced+cortical+infarction+in+the+mouse%5BTitle%5D)+AND+%22Brain+Res%22%5BJournal%5D)">Neurogenesis associated with endothelin-induced cortical infarction in the mouse.</a> Brain Res. 1167, 118-122 (2007).</li>
<li>Baskin, Y. K., Dietrich, W. D., Green, E. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Two+effective+behavioral+tasks+for+evaluating+sensorimotor+dysfunction+following+traumatic+brain+injury+in+mice%5BTitle%5D)+AND+%22J+Neurosci+Methods%22%5BJournal%5D)">Two effective behavioral tasks for evaluating sensorimotor dysfunction following traumatic brain injury in mice.</a> J Neurosci Methods. 129 (1), 87-93 (2003).</li>
<li>Li, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Chronic+behavioral+testing+after+focal+ischemia+in+the+mouse%3A+functional+recovery+and+the+effects+of+gender%5BTitle%5D)+AND+%22Exp+Neurol%22%5BJournal%5D)">Chronic behavioral testing after focal ischemia in the mouse: functional recovery and the effects of gender.</a> Exp Neurol. 187 (1), 94-104 (2004).</li>
<li>Clarke, J., Ploughman, M., Corbett, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+qualitative+and+quantitative+analysis+of+skilled+forelimb+reaching+impairment+following+intracerebral+hemorrhage+in+rats%5BTitle%5D)+AND+%22Brain+Res%22%5BJournal%5D)">A qualitative and quantitative analysis of skilled forelimb reaching impairment following intracerebral hemorrhage in rats.</a> Brain Res. , 204-212 (2007).</li>
<li>Montoya, C. P., Campbell-Hope, L. J., Pemberton, K. D., Dunnett, S. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+%27staircase+test%27%3A+a+measure+of+independent+forelimb+reaching+and+grasping+abilities+in+rats%5BTitle%5D)+AND+%22J+Neurosci+Methods%22%5BJournal%5D)">The 'staircase test': a measure of independent forelimb reaching and grasping abilities in rats.</a> J Neurosci Methods. 36 (2-3), 219-228 (1991).</li>
<li>Farr, T. D., Whishaw, I. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Quantitative+and+qualitative+impairments+in+skilled+reaching+in+the+mouse+%28Mus+musculus%29+after+a+focal+motor+cortex+stroke%5BTitle%5D)+AND+%22Stroke%22%5BJournal%5D)">Quantitative and qualitative impairments in skilled reaching in the mouse (Mus musculus) after a focal motor cortex stroke.</a> Stroke. 33 (7), 1869-1875 (2002).</li>
<li>Tennant, K. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+vermicelli+and+capellini+handling+tests%3A+simple+quantitative+measures+of+dexterous+forepaw+function+in+rats+and+mice%5BTitle%5D)+AND+%22J+Vis+Exp%22%5BJournal%5D)">The vermicelli and capellini handling tests: simple quantitative measures of dexterous forepaw function in rats and mice.</a> J Vis Exp. (41), (2010).</li>
<li>Clarkson, A. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((AMPA+receptor-induced+local+brain-derived+neurotrophic+factor+signaling+mediates+motor+recovery+after+stroke%5BTitle%5D)+AND+%22J+Neurosci%22%5BJournal%5D)">AMPA receptor-induced local brain-derived neurotrophic factor signaling mediates motor recovery after stroke.</a> J Neurosci. 31 (10), 3766-3775 (2011).</li>
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</ol>

The authors have no competing financial interests.

The key points to establish when quantifying paw-dragging behaviour in the cylinder test are the following: i) quantify the number of paw-drags versus total paw touches for each paw before brain injury to establish a baseline; ii) quantify the number of paw-drags versus total paw touches for each paw following the ischemic injury; and iii) discriminate between a paw-drag and the lateral motion of the paw along the cylinder wall during lateral rotation of the mouse&#8217;s torso.
Paw-dragging i...

The goal of neural regeneration strategies is to demonstrate both tissue repair and functional recovery. Functional recovery is typically evaluated with behavioural tests that measure functional deficits, in this case involving motor skills that are associated with damage to the specific brain regions. Traumatic brain injury or ischemic damage to the sensorimotor forelimb area of the cortex can be demonstrated by a number of behavioural tests. One such test, the cylinder test is used extensively in rats to assess functional deficits in forelimb activity1. The test has a low set-up cost requiring only a cylinder, camera and table with a transparent top. It is easy to administer as it is based on the natural exploratory behaviour of rodents, so pre-training and food deprivation or rewards are not required. Despite these numerous advantages, the cylinder test is under-utilized to assess forelimb deficits in mice following focal injuries to the forelimb sensorimotor cortex, which we attribute to the analysis of mouse behaviour in the cylinder test. Forelimb asymmetry is the classical measure of analysis for the cylinder test. When placed in the cylinder, rodents naturally explore the walls of the cylinder by rearing onto their hind limbs and touching the cylinder walls with their forelimb paws for postural balance. The number of paw touches with the wall with each forelimb is easily quantified by filming rodents during this exploration of the cylinder. Forelimb asymmetry occurs when the affected forelimb paw makes fewer touches with the wall than the unaffected forelimb paw and is indicative of damage to the contralateral sensorimotor cortex. In rats, intra-cortical injections of the vasoconstrictive agent, Endothelin (ET-1), into the forelimb sensorimotor cortex causes a focal ischemic lesion which results in behavioural deficits in the contralateral forelimb. Deficits in contralateral forelimb use are readily detected as changes in forelimb asymmetry in the cylinder test in rats1-3. In contrast to rats however, changes in forelimb asymmetry are variable and less consistent in mice following comparable ET-1 injections4-6. Here we demonstrate a novel analysis of forelimb behaviour in the cylinder test &#8211; analysis of paw-dragging behaviour. We have previously shown that paw-dragging analysis is a more sensitive measure of damage to the forelimb sensorimotor cortex in mice than the classical forelimb asymmetry analysis and therefore is applicable to a variety of focal cortical injury models.
Examination of how the forepaw contacts the cylinder wall following ischemic damage to the forelimb sensorimotor cortex revealed a novel behaviour in mice - paw-dragging4. A paw-drag occurs when a mouse stands on its rear legs to explore the cylinder wall then drags its affected (contra-lesional) paw along the cylinder wall towards its midline or down the wall while its unaffected forepaw provides postural support against the wall. Paw-drags rarely occur in uninjured mice therefore the appearance of a paw-drag is a positive indicator of injury to the forelimb sensorimotor cortex4. We have previously quantified paw-dragging behaviour in mice following ET-1 ischemic damage to the forelimb sensorimotor cortex and have shown sustained paw-dragging behaviour in mice up to two weeks post-stroke4. Here we show that paw-dragging behaviour is sustained up to four weeks post-stroke. Analysis of paw-dragging behaviour provides a novel and sensitive tool for assessing focal ischemic damage to the forelimb sensorimotor cortex in mice. Its inexpensive set-up, ease of administration and scoring make this a simple, yet useful tool to rapidly assess forelimb behavioural deficits in mice.

<table><tbody><tr><td>Plexi-glass cylinder</td><td></td><td></td><td>17.5 cm high, 9.5 cm outer diameter, 8.8 cm inner diameter, wall thickness 0.35 cm (or 3.5 mm)</td></tr><tr><td>viewing table</td><td></td><td></td><td>54x56x66.5 cm (width x length x height), top of table is a 51x51 cm sheet of plexiglass.</td></tr><tr><td>mirror</td><td></td><td></td><td>34x58 cm mirror</td></tr><tr><td>video camera</td><td>Sony</td><td>DCR-SR42</td><td>Video camera with onboard storage, SD functionality, 40x optical zoom</td></tr><tr><td>computer</td><td>Dell</td><td>Optiplex 760</td><td>Processor: Intel, 3.0 GHz, Memory 4.00GB (RAM)&amp;nbsp;</td></tr><tr><td>computer monitor</td><td>Samsung</td><td>S22C350H</td><td></td></tr><tr><td>Excel (Microsoft Office Professional Plus)</td><td>Microsoft</td><td>v14.0.7106.5003</td><td></td></tr><tr><td>VLC Media Player</td><td>Video LAN</td><td>v2.1.2</td><td>Media player with playback speed modulation and video support</td></tr><tr><td>External Hard Drive</td><td>Western Digital</td><td>WDBAAU0020HBK-01</td><td>2 TB</td></tr></tbody></table>

paw-dragging: a novel, sensitive analysis of the mouse cylinder test

The cylinder test is routinely used to predict focal ischemic damage to the forelimb motor cortex in rodents. When placed in the cylinder, rodents explore by rearing and touching the walls of the cylinder with their forelimb paws for postural support. Following ischemic injury to the forelimb sensorimotor cortex, rats rely more heavily on their unaffected forelimb paw for postural support resulting in fewer touches with their affected paw which is termed forelimb asymmetry. In contrast, focal ischemic damage in the mouse brain fails to result in comparable consistent deficits in forelimb asymmetry. While forelimb asymmetry deficits are infrequently observed, mice do demonstrate a novel behaviour post stroke termed &#8220;paw-dragging&#8221;. Paw-dragging is the tendency for a mouse to drag its affected paw along the cylinder wall rather than directly push off from the wall when dismounting from a rear to a four-legged stance. We have previously demonstrated that paw-dragging behaviour is highly sensitive to small cortical ischemic injuries to the forelimb motor cortex. Here we provide a detailed protocol for paw-dragging analysis. We define what a paw-drag is and demonstrate how to quantify paw-dragging behaviour. The cylinder test is a simple and inexpensive test to administer and does not require pre-training or food deprivation strategies. In using paw-dragging analysis with the cylinder test, it fills a niche for predicting cortical ischemic injuries such as photothrombosis and Endothelin-1 (ET-1)-induced ischemia &#8211; two models that are ever-increasing in popularity and produce smaller focal injuries than middle cerebral artery occlusion. Finally, measuring paw-dragging behaviour in the cylinder test will allow studies of functional recovery after cortical injury using a wide cohort of transgenic mouse strains where previous forelimb asymmetry analysis has failed to detect consistent deficits.

We have previously demonstrated that paw-dragging behaviour appears following a focal ischemic injury to the forelimb sensorimotor cortex and is a positive indicator of damage4. Intra-cortical injections of ET-1 into the forelimb sensorimotor cortex were used to induce an ischemic lesion (Figure 8A,B). This study examined whether paw-dragging behaviour extended for longer than 14 days post-injury for its potential use to assess functional recovery. Mice were tested in the cylinder test on the...

Watch this Scientific Journal Video about Paw-Dragging: a Novel, Sensitive Analysis of the Mouse Cylinder Test at JoVE.com

Paw-Dragging: a Novel, Sensitive Analysis of the Mouse Cylinder Test

Classical forelimb asymmetry analysis of the cylinder test is routinely used to assess behavioural deficits in rats following brain injury or stroke; however, it fails to detect consistent deficits in mice. This study demonstrates that quantifying paw-dragging behaviour is a more sensitive analysis of brain injury in mice.

The cylinder test is routinely used to predict focal ischemic damage to the forelimb motor cortex in rodents. When placed in the cylinder, rodents explore ...

paw-dragging-a-novel-sensitive-analysis-of-the-mouse-cylinder-test

Research

JoVE Journal

Behavior

23.5K Views.  Memorial University of Newfoundland. Classical forelimb asymmetry analysis of the cylinder test is routinely used to assess behavioural deficits in rats following brain injury or stroke; however, it fails to detect consistent deficits in mice. This study demonstrates that quantifying paw-dragging behaviour is a more sensitive analysis of brain injury in mice.

Video: Paw-Dragging: a Novel, Sensitive Analysis of the Mouse Cylinder Test

Assessment of Sensorimotor Function in Mouse Models of Parkinson's Disease

Sensitive and reliable behavioral outcome measures are essential to the evaluation of potential therapeutic treatments in preclinical trials for many neurodegenerative diseases. In Parkinson's disease, sensorimotor tests sensitive to varying degrees of nigrostriatal dysfunction are fundamental for testing the efficacy of potential therapeutics. Reliable and quite elegant sensorimotor measures exist for rats, however many of these tests measure sensorimotor asymmetry within the rat and are not entirely suitable for the newer genetic mouse models of PD. We have put together a battery of sensorimotor tests inspired by the sensitive tests in rats and adapted for mice. The test battery highlighted in this study is chosen for a) its sensitivity in a wide variety of mouse models of PD, b) its ease in implementing into a study, and c) its low expense. These tests have proven useful in characterizing novel genetic mouse models of PD as well as in testing potential disease-modifying therapies.

In Parkinson's disease and movement disorders in general, sensitive and reliable behavioral assays are essential for testing novel potential therapeutics. Here, we describe a manageable battery of sensorimotor tests for mice that are sensitive to varying degrees of injury to the nigrostriatal system and useful for preclinical studies.

Sensitive and  reliable behavioral outcome measures are essential to the evaluation of  potential therapeutic treatments in preclinical trials for many  ...

The Vermicelli and Capellini Handling Tests: Simple quantitative measures of dexterous forepaw function in rats and mice

Previous characterizations of rodent eating behavior have revealed that they use coordinated forepaw movements to manipulate food pieces. We have extended upon this work to develop a simple quantitative measure of forepaw dexterity that is sensitive to lateralized impairments and age-dependent changes. Rodents learn skillful forepaw and digit movements to manage thin pasta pieces, which they eagerly consume. We have previously described methods for quantifying vermicelli handling in rats and showed that the measures are very sensitive to forelimb impairments resulting from unilateral ischemic lesions, middle cerebral artery occlusions and unilateral striatal dopamine depletion [Allred, R.P., Adkins, D.L., Woodlee, M.T., Husbands, L.C., Maldonado M.A., Kane, J.R., Schallert, T. &amp; Jones, T.A. The Vermicelli Handling Test: a simple quantitative measure of dexterous forepaw function in rats. J. Neurosci. Methods 170, 229-244 (2008)]. Here we present a more detailed protocol for this test in rats and compare it with a newly developed version for mice, the Capellini Handling Test. Rats and mice are videotaped while handling short lengths of uncooked vermicelli or capellini pasta, respectively, with a camera positioned to optimize the view of paw movements. Slow motion video playback allows for the identification of forepaw adjustments, defined as any distinct removal and replacement of the paw, or of any number of digits, on the pasta piece after eating commences. Forepaw adjustments per piece are averaged over trials per each testing session. Repeated testing permits sensitive quantitative analysis of changes in forepaw dexterity over time. Protocols for pre-testing habituation and handling practice, as well as procedures for characterizing atypical handling patterns, are described. Because rats and mice perform the pasta handling tests slightly differently, species-specific differences in administration and scoring of these tests are highlighted. All animal use was in accordance with protocols approved by the University of Texas at Austin Animal Care and Use Committee.

The Vermicelli and Capellini Handling Tests of forepaw dexterity take advantage of the natural inclination of rodents to manipulate food items using skillful forepaw and digit movements. Animals are videotaped while handling short strands of uncooked dry pasta. Slow motion video playback allows for the quantification of forepaw adjustments.

Previous characterizations of rodent eating behavior have revealed that they use coordinated forepaw movements to manipulate food pieces. We have extended ...

Neuroscience

The Sciatic Nerve Cuffing Model of Neuropathic Pain in Mice

Neuropathic pain arises as a consequence of a lesion or a disease affecting the somatosensory system. This syndrome results from maladaptive changes in injured sensory neurons and along the entire nociceptive pathway within the central nervous system. It is usually chronic and challenging to treat. In order to study neuropathic pain and its treatments, different models have been developed in rodents. These models derive from known etiologies, thus reproducing peripheral nerve injuries, central injuries, and metabolic-, infectious- or chemotherapy-related neuropathies. Murine models of peripheral nerve injury often target the sciatic nerve which is easy to access and allows nociceptive tests on the hind paw. These models rely on a compression and/or a section. Here, the detailed surgery procedure for the &#34;cuff model&#34; of neuropathic pain in mice is described. In this model, a cuff of PE-20 polyethylene tubing of standardized length (2 mm) is unilaterally implanted around the main branch of the sciatic nerve. It induces a long-lasting mechanical allodynia, i.e., a nociceptive response to a normally non-nociceptive stimulus that can be evaluated by using von Frey filaments. Besides the detailed surgery and testing procedures, the interest of this model for the study of neuropathic pain mechanism, for the study of neuropathic pain sensory and anxiodepressive aspects, and for the study of neuropathic pain treatments are also discussed.

Neuropathic pain is a consequence of a lesion or disease affecting the somatosensory system. The &#8220;cuff model&#8221; of neuropathic pain in mice consists of the implantation of a polyethylene cuff around the main branch of the sciatic nerve. Mechanical allodynia is tested using von Frey filaments.

Neuropathic pain arises as a consequence of a lesion or a disease affecting the somatosensory system. This syndrome results from maladaptive changes in ...

Medicine

Measuring Changes in Tactile Sensitivity in the Hind Paw of Mice Using an Electronic von Frey Apparatus

Measuring inflammation-induced changes in thresholds of hind paw withdrawal from mechanical pressure is a useful technique to assess changes in pain perception in rodents. Withdrawal thresholds can be measured first at baseline and then following drug, venom, injury, allergen,&#160;or otherwise evoked inflammation by applying an accurate force on very specific areas of the skin. An electronic von Frey apparatus allows precise assessment of mouse hind paw withdrawal thresholds that are not limited by the available filament sizes in contrast to classical von Frey measurements. The ease and rapidity of measurements allow for incorporation of assessment of tactile sensitivity outcomes in diverse models of rapid-onset inflammatory and neuropathic pain as multiple measurements can be taken within a short time period. Experimental measurements for individual rodent subjects can be internally controlled against individual baseline responses and exclusion criteria easily established to standardize baseline responses within and across experimental groups. Thus, measurements using an electronic von Frey apparatus represent a useful modification of the well-established classical von Frey filament-based assays for rodent mechanical allodynia that may also be applied to other nonhuman mammalian models.

Electronic von Frey measurements are an effective and improved alternative to classical von Frey filaments, as they allow rapid and precise measurement of changes in rodent mechanical withdrawal thresholds to continuously applied pressure stimuli before and after an inflammatory event.

Measuring inflammation-induced changes in thresholds of hind paw withdrawal from mechanical pressure is a useful technique to assess changes in pain ...

Urokinase-type Plasminogen Activator-induced Mouse Back Pain Model

A model of persisting lower back pain can be induced in mice with the simple methodology described herein. Step-by-step methods for simple, rapid induction of a persisting back pain model in mice are provided here using an injection of urokinase-type plasminogen activator (urokinase), a serine protease present in humans and other animals. The methodology for induction of persisting lower back pain in mice involves a simple injection of urokinase along the ligamentous insertion region of the lumbar spine. The urokinase inflammatory agent activates plasminogen to plasmin. Typically, the model can be induced within 10 min and hypersensitivity persists for at least 8 weeks.
Hypersensitivity, gait disturbance, and other standard anxiety- and depression-like measures can be tested in the persisting model.&#160;Back pain is the most prevalent type of pain. To improve awareness of back pain, the International Association for the Study of Pain (IASP) named 2021 the &#34;Global Year about Back Pain&#34; and 2022 the &#34;Global Year for Translating Pain Knowledge to Practice.&#34; One limitation of the therapeutic advancement of pain therapeutics is the lack of suitable models for testing persistent and chronic pain. The&#160;features of this model&#160;are suitable for testing potential therapeutics aimed at the reduction of back pain and its ancillary characteristics, contributing to IASP&#39;s naming 2022 as the Global Year for Translating Pain Knowledge to Practice.

Methods for simple, rapid induction of a back pain model in mice are provided here using an intraligament injection of urinary plasminogen activator.

A model of persisting lower back pain can be induced in mice with the simple methodology described herein. Step-by-step methods for simple, rapid ...

The Monoiodoacetate Model of Osteoarthritis Pain in the Mouse

A major symptom of patients with osteoarthritis (OA) is pain that&#160;is triggered by peripheral as well as central changes within the pain pathways. The current treatments for OA pain such as NSAIDS or opiates are neither sufficiently effective nor devoid of detrimental side effects. Animal models of OA are being developed to improve our understanding of OA-related pain mechanisms and define novel pharmacological targets for therapy. Currently available models of OA in rodents include surgical and chemical interventions into one knee joint. The monoiodoacetate (MIA) model has become a standard for modelling joint disruption in OA in both rats and mice. The model, which is easier to perform in the rat, involves injection of MIA into a knee joint that induces rapid pain-like responses in the ipsilateral limb, the level of which can be controlled by injection of different doses. Intra-articular injection of MIA disrupts chondrocyte glycolysis by inhibiting glyceraldehyde-3-phosphatase dehydrogenase and results in chondrocyte death, neovascularization, subchondral bone necrosis and collapse, as well as inflammation. The morphological changes of the articular cartilage and bone disruption are reflective of some aspects of patient pathology. Along with joint damage, MIA injection induces referred mechanical sensitivity in the ipsilateral hind paw and weight bearing deficits that are measurable and quantifiable. These behavioral changes resemble some of the symptoms reported by the patient population, thereby validating the MIA injection in the knee as a useful and relevant pre-clinical model of OA pain.
The aim of this article is to describe the methodology of intra-articular injections of MIA and the behavioral recordings of the associated development of hypersensitivity with a mind to highlight the necessary steps to give consistent and reliable recordings.

Osteoarthritis (OA), or degenerative joint disease, is a debilitating condition associated with pain that remains only partially controlled by available analgesics. Animal models are being developed to improve our understanding of OA-related pain mechanisms. Here we describe the methodology for the monoiodoacetate model of OA pain in the mouse.

A major symptom of patients with osteoarthritis (OA) is pain that&#160;is triggered by peripheral as well as central changes within the pain pathways. The ...

Automated Gait Analysis in Mice with Chronic Constriction Injury

The von Frey test is a classical method that has been widely used to examine the sensory function of neuropathic pain animals. However, it has some disadvantages such as subjective data and the requirement of a skilled, experienced experimenter. To date, a variety of modifications have improved the von Frey method, but it still has a few limitations. Recent reports have suggested that gait analysis produces more accurate and objective data from the neuropathic animals. This protocol demonstrates how to perform the automated gait analysis to determine the degree of neuropathic pain in mice. After several days of acclimation, the mice were allowed to walk freely on the glass floor to illuminate footprints. Then, quantification of the footprints and gait were performed through video clips with automatic analysis of various walking parameters, such as area of paw print, swing time, angle of paw, etc.
The main purpose of this study is to describe the methodology of automated gait analysis and briefly compare it with data from the classical sensory test using von Frey filament.

The precise assessment of pain response in a neuropathic animal model is critical to investigate the pathophysiology of pain diseases and develop new analgesics. We present a sensitive and objective method to determine the sensory function of the rodent hind paw by an automated gait analysis system.

The von Frey test is a classical method that has been widely used to examine the sensory function of neuropathic pain animals. However, it has some ...

Establishing a Mouse Model of a Pure Small Fiber Neuropathy with the Ultrapotent Agonist of Transient Receptor Potential Vanilloid Type 1

Patients with diabetes mellitus (DM) or those experiencing the neurotoxic effects of chemotherapeutic agents may develop sensation disorders due to degeneration and injury of small-diameter sensory neurons, referred to as small fiber neuropathy. Present animal models of small fiber neuropathy affect both large- and small-diameter sensory fibers and thus create a neuropathology too complex to properly assess the effects of injured small-diameter sensory fibers. Therefore, it is necessary to develop an experimental model of pure small fiber neuropathy to adequately examine these issues. This protocol describes an experimental model of small fiber neuropathy specifically affecting small-diameter sensory nerves with resiniferatoxin (RTX), an ultrapotent agonist of transient receptor potential vanilloid type 1 (TRPV1), through a single dose of intraperitoneal injection, referred to as RTX neuropathy. This RTX neuropathy showed pathological manifestations and behavioral abnormalities that mimic the clinical characteristics of patients with small fiber neuropathy, including intraepidermal nerve fiber (IENF) degeneration, specifically injury in small-diameter neurons, and induction of thermal hypoalgesia and mechanical allodynia. This protocol tested three doses of RTX (200, 50, and 10 &#181;g/kg, respectively) and concluded that a critical dose of RTX (50 &#181;g/kg) is required for the development of typical small fiber neuropathy manifestations, and prepared a modified immunostaining procedure to investigate IENF degeneration and neuronal soma injury. The modified procedure is fast, systematic, and economic. Behavioral evaluation of neuropathic pain is critical to reveal the function of small-diameter sensory nerves. The evaluation of mechanical thresholds in experimental rodents is particularly challenging and this protocol describes a customized metal mesh that is suitable for this type of assessment in rodents. In summary, RTX neuropathy is a new and easily established experimental model to evaluate the molecular significance and intervention underlying neuropathic pain for the development of therapeutic agents.

This study establishes an experimental model of pure small fiber neuropathy with resiniferatoxin (RTX). A unique dose of RTX (50 &#181;g/kg) is optimal for developing a small fiber neuropathy model that mimics patient characteristics and could help investigate the nociceptive molecular significance underlying neuropathic pain.

Patients with diabetes mellitus (DM) or those experiencing the neurotoxic effects of chemotherapeutic agents may develop sensation disorders due to ...

Development of Recombinant Proteins to Treat Chronic Pain

Chronic pain is difficult to treat and new approaches to resolve persistent pain are urgently needed. Anti-inflammatory cytokines are promising candidates for treating debilitating pain conditions due to their capacity to regulate aberrant neuro-immune interactions. However, physiologically they work in a network of various cytokines, and therefore their therapeutic effect may not be optimal when used as stand-alone drugs. To overcome this limitation, we developed a fusion protein of the anti-inflammatory cytokines IL4 and IL10. Here, we describe the methods for production and quality control of IL4-10 recombinant fusion protein and we test the effectiveness of the IL4-10 fusion protein to resolve pain in a mouse model of persistent inflammatory pain.

In this paper we provide details for the methods of production and quality control of an IL4-10 recombinant fusion protein. We also show how to test the effectiveness of this protein to resolve pain in a mouse model of inflammatory pain.

Chronic pain is difficult to treat and new approaches to resolve persistent pain are urgently needed. Anti-inflammatory cytokines are promising candidates ...

Mechanical Conflict-Avoidance Assay to Measure Pain Behavior in Mice

Pain comprises of both sensory (nociceptive) and affective (unpleasant) dimensions. In preclinical models, pain has traditionally been assessed using reflexive tests that allow inferences regarding pain's nociceptive component but provide little information about the affective or motivational component of pain. Developing tests that capture these components of pain are therefore translationally important. Hence, researchers need to use non-reflexive behavioral assays to study pain perception at that level. Mechanical conflict-avoidance (MCA) is an established voluntary non-reflexive behavior assay, for studying motivational responses to a noxious mechanical stimulus in a 3 chamber paradigm. A change in a mouse's location preference, when faced with competing noxious stimuli, is used to infer the perceived unpleasantness of bright light versus tactile stimulation of the paws. This protocol outlines a modified version of the MCA assay which pain researchers can use to understand affective-motivational responses in a variety of mouse pain models. Though not specifically described here, our example MCA data use the intraplantar complete Freund's adjuvant (CFA), spared nerve injury (SNI), and a fracture/casting model as pain models to illustrate the MCA procedure.

The mechanical conflict-avoidance assay is used as a non-reflexive readout of pain sensitivity in mice which can be used to better understand affective-motivational responses in a variety of mouse pain models.

Pain comprises of both sensory (nociceptive) and affective (unpleasant) dimensions. In preclinical models, pain has traditionally been assessed using ...