This work was supported by the National Natural Science Foundation of China, Nos. 82102314 (to ZSJ), and 32170977 (to HSL) and Natural Science Foundation of Guangdong Province, Nos. 2022A1515010438 (to ZSJ) and 2022A1515012306 (to HSL). This study was supported by the Clinical Frontier Technology Program of the First Affiliated Hospital of Jinan University, China, Nos. JNU1AF- CFTP- 2022- a01206 (to HSL). This study was supported by Guangzhou Science and Technology Plan Project, Nos. 202201020018 (to HSL), 2023A04J1284 (to ZSJ) and 2023A03J1024 (to HSL).

The studies involving animals were reviewed and approved by the Ethics Committee of Jinan University.
1. Anesthetization of animals and T10 spinal laminectomy
<ol>
	<li>Use 8 weeks-old female young adult C57/6J mice for this study. Anesthetize the mice by intraperitoneal injection of ketamine (100 mg/kg) and&#160;diazepam&#160;(5 mg/kg). Check for successful anesthetization indicated by loss of pain reflex. Apply vet ointment on eyes to prevent dryness under anesthesia.</li>
	<li>Shave the hair on the back of the mice using a shaver to reveal the skin. Disinfect the skin with three alternating rounds of iodophor and alcohol.</li>
	<li>Make 2.5 cm medial longitudinal incision in the dorsal skin using a scalpel and expose the spine at the T9-T11 level using tweezers.</li>
	<li>Bilaterally fix T10 facets using a spinal fixator. Ensure the spine is stably fixed. Ensure that the paravertebral muscles are stripped and remove the spinous process as well as laminae using micro-grinding drill to expose the spinal cord of the T10 segment.</li>
</ol>
2. Contusion of the T10 spinal cord using the G smart SCI system
<ol>
	<li>Turn on the switch and wait for the device to automatically return to its original state. Place the spinal fixator into the G smart SCI system and secure it using screws.</li>
	<li>Using the operation touch screen (Figure 2A), set damage parameters, including impact speed (1 m/s), impact depth (0.5 mm, 0.8 mm, and 1.1 mm for three different sets of mice) and dwell time (500 ms)15.</li>
	<li>Align the laser rangefinder at the center of the exposed spinal cord by moving the platform. (Figure 2B)</li>
	<li>Click the Ready button on the touch screen (Figure 2C). The impact head will automatically adjust to a specific height based on setting parameters. The carrier table automatically moves the spinal cord impact site below the impact head.</li>
	<li>Manually press the impact head to further determine the impact site. Click the Start button, the impact head will hit the spinal cord based on set parameters.</li>
	<li>Remove the mice from the device and observe under a Stereomicroscope (20x) to determine spinal cord injury (Figure 3). To determine the success of model development, observe local congestion, collapse, and spinal membrane rupture.</li>
	<li>Suture the muscle, fascia and skin layer by layer using 3-0 sutures. Place the mice in a warm box and wait for their recovery.</li>
</ol>
3. Post-operative care
<ol>
	<li>Inject meloxicam (5 mg/kg) subcutaneously daily for 7 days after surgery. Manually empty the bladder every 8 h until bladder functions are restored.</li>
	<li>At 14 days after operation, remove the suture threads.</li>
</ol>
4. Testing effects of spinal injury
<ol>
	<li>Calculate the BMS scores for mice from the first postoperative day16,17.</li>
	<li>On the 30th postoperative day, perform animal behavioral experiments, including catwalk, foot fault and rotarod16,17. Catwalk: Record distance of 45 cm; Maximum run duration 8 s; Camera gain 28.02; Intensity threshold 0.01. Foot fault: Record 60 steps for each mouse. Rotarod: Speed 20 rpm. Record the time for the mouse to fall and record it as 120 s for more than 120 s.</li>
	<li>On the 31st postoperative day, anesthetize the mice by intraperitoneal injection of ketamine (100 mg/kg) and&#160;diazepam&#160;(5 mg/kg) and then euthanize the mice by perfusion using 4% PFA. Remove the spinal cord carefully, and intercept 5 mm above and below the injury site for paraffin embedding. Make a 5 &#181;m section of the center of the mouse spinal cord injury and perform Hematoxylin and eosin staining17.</li>
	<li>For statistical analysis use commercial software. Express data as mean &#177; standard error of the mean (SEM) and compare using one-way ANOVA; p &#60; 0.05 was considered significant.</li>
</ol>

A Spinal Cord Injury Contusion Device for Accurate Mouse Models

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	<li>Venkatesh, K., Ghosh, S. K., Mullick, M., Manivasagam, G., Sen, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spinal+cord+injury:+pathophysiology,+treatment+strategies,+associated+challenges,+and+future+implications.">Spinal cord injury: pathophysiology, treatment strategies, associated challenges, and future implications.</a> Cell and Tissue Research. 377 (2), 125-151 (2019).</li><li>Chiu, C. W., Cheng, H., Hsieh, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Contusion+Spinal+Cord+Injury+Rat+Model.">Contusion Spinal Cord Injury Rat Model.</a> Bio Protocol. 7 (12), e2337 (2017).</li><li>Thygesen, M. M., Guldb&#230;k-Svensson, F., Rasmussen, M. M., Lauridsen, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Contusion+Spinal+Cord+Injury+via+a+Microsurgical+Laminectomy+in+the+Regenerative+Axolotl.">Contusion Spinal Cord Injury via a Microsurgical Laminectomy in the Regenerative Axolotl.</a> Journal of Visualized Experiments. (152), 60337 (2019).</li><li>Anderson, T. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+controlled+pneumatic+technique+for+experimental+spinal+cord+contusion.">A controlled pneumatic technique for experimental spinal cord contusion.</a> Journal of Neuroscience Methods. 6 (4), 327-333 (1982).</li><li>Allen, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SURGERY+OF+EXPERIMENTAL+LESION+OF+SPINAL+CORD+EQUIVALENT+TO+CRUSH+INJURY+OF+FRACTURE+DISLOCATION+OF+SPINAL+COLUMN:+A+PRELIMINARY+REPORT.">SURGERY OF EXPERIMENTAL LESION OF SPINAL CORD EQUIVALENT TO CRUSH INJURY OF FRACTURE DISLOCATION OF SPINAL COLUMN: A PRELIMINARY REPORT.</a> Journal of the American Medical Association. LVII (11), 878-880 (1911).</li><li>Cheriyan, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spinal+cord+injury+models:+a+review.">Spinal cord injury models: a review.</a> Spinal Cord. 52 (8), 588-595 (2014).</li><li>Yan, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+modified+impactor+for+establishing+a+graded+contusion+spinal+cord+injury+model+in+rats.">A modified impactor for establishing a graded contusion spinal cord injury model in rats.</a> Annals of Translational Medicine. 10 (8), 436 (2022).</li><li>Gruner, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+monitored+contusion+model+of+spinal+cord+injury+in+the+rat.">A monitored contusion model of spinal cord injury in the rat.</a> Journal of Neurotrauma. 9 (2), 123-126 (1992).</li><li>Ghnenis, A. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+the+Cardiometabolic+Disorders+after+Spinal+Cord+Injury+in+Mice.">Evaluation of the Cardiometabolic Disorders after Spinal Cord Injury in Mice.</a> Biology (Basel). 11 (4), 495 (2022).</li><li>Scheff, S. W., Rabchevsky, A. G., Fugaccia, I., Main, J. A., Lumpp, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+modeling+of+spinal+cord+injury:+characterization+of+a+force-defined+injury+device.">Experimental modeling of spinal cord injury: characterization of a force-defined injury device.</a> Journal of Neurotrauma. 20 (2), 179-193 (2003).</li><li>Hong, Y. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrasound+stimulation+improves+inflammatory+resolution,+neuroprotection,+and+functional+recovery+after+spinal+cord+injury.">Ultrasound stimulation improves inflammatory resolution, neuroprotection, and functional recovery after spinal cord injury.</a> Scientific Reports. 12 (1), 3636 (2022).</li><li>Noyes, D. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electromechanical+impactor+for+producing+experimental+spinal+cord+injury+in+animals.">Electromechanical impactor for producing experimental spinal cord injury in animals.</a> Medical &amp; Biological Engineering &amp; Computing. 25 (3), 335-340 (1987).</li><li>Stokes, B. T., Noyes, D. H., Behrmann, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+electromechanical+spinal+injury+technique+with+dynamic+sensitivity.">An electromechanical spinal injury technique with dynamic sensitivity.</a> Journal of Neurotrauma. 9 (3), 187-195 (1992).</li><li>Pearse, D. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Histopathological+and+behavioral+characterization+of+a+novel+cervical+spinal+cord+displacement+contusion+injury+in+the+rat.">Histopathological and behavioral characterization of a novel cervical spinal cord displacement contusion injury in the rat.</a> Journal of Neurotrauma. 22 (6), 680-702 (2005).</li><li>Wu, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Tissue+Displacement-based+Contusive+Spinal+Cord+Injury+Model+in+Mice.">A Tissue Displacement-based Contusive Spinal Cord Injury Model in Mice.</a> Journal of Visualized Experiments. (124), 54988 (2017).</li><li>Forgione, N., Chamankhah, M., Fehlings, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Mouse+Model+of+Bilateral+Cervical+Contusion-Compression+Spinal+Cord+Injury.">A Mouse Model of Bilateral Cervical Contusion-Compression Spinal Cord Injury.</a> Journal of Neurotrauma. 34 (6), 1227-1239 (2017).</li><li>Ji, Z. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+bioactive+iridium+metal-complex+alleviates+spinal+cord+injury+via+ROS+scavenging+and+inflammation+reduction.">Highly bioactive iridium metal-complex alleviates spinal cord injury via ROS scavenging and inflammation reduction.</a> Biomaterials. 284, 121481 (2022).</li><li>Chen, C., Qiao, X., Liu, W., Fekete, C., Reinhardt, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epidemiology+of+spinal+cord+injury+in+China:+A+systematic+review+of+the+chinese+and+english+literature.">Epidemiology of spinal cord injury in China: A systematic review of the chinese and english literature.</a> Spinal Cord. 60 (12), 1050-1061 (2022).</li><li>Flack, J. A., Sharma, K. D., Xie, J. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Delving+into+the+recent+advancements+of+spinal+cord+injury+treatment:+a+review+of+recent+progress.">Delving into the recent advancements of spinal cord injury treatment: a review of recent progress.</a> Neural Regeneration Research. 17 (2), 283-291 (2022).</li><li>Khuyagbaatar, B., Kim, K., Kim, Y. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conversion+Equation+between+the+Drop+Height+in+the+New+York+University+Impactor+and+the+Impact+Force+in+the+Infinite+Horizon+Impactor+in+the+Contusion+Spinal+Cord+Injury+Model.">Conversion Equation between the Drop Height in the New York University Impactor and the Impact Force in the Infinite Horizon Impactor in the Contusion Spinal Cord Injury Model.</a> Journal of Neurotrauma. 32 (24), 1987-1993 (2015).</li><li>Alizadeh, A., Dyck, S. M., Karimi-Abdolrezaee, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Traumatic+Spinal+Cord+Injury:+An+Overview+of+Pathophysiology,+Models+and+Acute+Injury+Mechanisms.">Traumatic Spinal Cord Injury: An Overview of Pathophysiology, Models and Acute Injury Mechanisms.</a> Frontiers in Neurology. 10, 282 (2019).</li><li>Bilgen, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+device+for+experimental+modeling+of+central+nervous+system+injuries.">A new device for experimental modeling of central nervous system injuries.</a> Neurorehabilitation and Neural Repair. 19 (3), 219-226 (2005).</li><li>Khan, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=GSNOR+and+ALDH2+alleviate+traumatic+spinal+cord+injury.">GSNOR and ALDH2 alleviate traumatic spinal cord injury.</a> Brain Research. 1758, 147335 (2021).</li></ol>

The authors declare no competing financial interests.

Spinal cord injury can lead to sensory and motor deficits, which can result in severe physical and mental impairments. In China, incidences of spinal cord injuries in different provinces vary from 14.6 to 60.6 per million18. The increase in the prevalence of SCI will put more pressure on the healthcare system. Currently, there are limited effective treatment option for spinal cord injury, injuries because its pathomechanisms and repair processes are yet to be fully understood19</...

Spinal cord injury usually results in permanent spinal cord dysfunction below the injured segment. It is mostly caused by objects striking the spine and hyperextension of the spine, such as traffic accidents and falls1. Due to the limited availability of effective treatment options for spinal cord injury, elucidation of the pathogenesis of spinal cord injuries using animal models will be informative for the development of appropriate treatment approaches. The contusion model of spinal cord injury caused by impact on the spinal cord results in the development of animal models with similar pathologies to most clinical spinal cord injury cases2,3. Therefore, it is important to produce accurate, reproducible, and convenient animal models for spinal cord injury contusion.
Since Allen&#39;s invention of the first animal model of spinal cord injury in 1911, there have been major advances in the development of instruments for establishing spinal cord injury animal models4,5. Based on injury mechanisms, spinal cord injury models are classified as contusion, compression, distraction, dislocation, transection, or chemical6. Among them, the contusion models, which use external forces to displace and injure the spinal cord, are closest to the clinical etiology of most spinal cord injury patients. Therefore, the contusion model has been used by many investigators in spinal cord injury studies3,7. Various instruments are used to develop spinal cord injury contusion models. The New York University (NYU)-multicenter animal spinal cord injury studies (MASCIS) impactor produces spinal cord injury contusions by weight-drop device8. After several updated versions, the MASCIS impactor is widely used to develop spinal cord injury contusion animal models9. However, when the impact rod of MASCIS falls and hits the spinal cord, multiple injuries may occur, which affects the degree of injury in spinal cord injury models. Moreover, achieving mechanical precision to ensure the accuracy of the instrument and the repeatability of the manufacturing model is also challenging. The infinite horizon impactors cause contusions by controlling the force applied to the spinal cord rather than heavy drops10. It uses a computer connected to a sensor to directly measure the impact force between the impactor and the spinal cord. When the threshold is reached, the impactor is immediately retracted, thereby avoiding weight rebound and improving accuracy10,11. However, the use of this fine motor modality to inflict damage can result in inconsistent damage and functional deficits6. The Ohio State University (OSU) device compresses the dorsal surface of the spinal cord at a transient rate by an electromagnetic driver12,13. This device is similar to the infinite horizon impactors, as it uses short-distance compressions to cause spinal cord injuries. However, it has various limitations in that initial determination of the zero point will cause errors due to the presence of the cerebrospinal fluid6,14. In summary, there are many instruments that can be used to develop spinal cord injury contusion animal models, but they all have some limitations that lead to insufficient accuracy and reproducibility of animal models. Therefore, in order to more accurately, conveniently and reproducibly create mouse contusion models of spinal cord injury, an automated and intelligent spinal cord injury impactor is needed.
We present a novel spinal cord injury impactor, Guangzhou Jinan University smart spinal cord injury system (G smart SCI system; Figure 1), for producing spinal cord injury contusion models. The device uses a laser rangefinder as a positioning device, combined with an automated mobile platform to automate strikes according to set strike parameters, including strike speed, strike depth and dwell time. Automated operation reduces human factors and improves the accuracy as well as reproducibility of animal models.

<table><tbody><tr><td>0.01M PBS (powder, pH7.2-7.4)</td><td>Solarbio Life Sciences</td><td>P1010</td><td></td></tr><tr><td>2,2,2-Tribromoethanol</td><td>Macklin</td><td>75-80-9</td><td></td></tr><tr><td>4% paraformaldehyde tissue fixative</td><td>Biosharp life science</td><td>BL539A</td><td></td></tr><tr><td>Biomicroscope</td><td>Leica</td><td>LCC50 HD</td><td></td></tr><tr><td>CatWalk&amp;nbsp;</td><td>Noldus Information Technology</td><td>CatWalk XT 9.1</td><td></td></tr><tr><td>Cover glass</td><td>CITOTEST Scientific</td><td>10212432C</td><td></td></tr><tr><td>Embedding machine</td><td>Changzhou Zhongwei Electronic Instrument</td><td>BMJ-A</td><td></td></tr><tr><td>Ethanol absolute</td><td>DAMAO</td><td>64-17-5</td><td></td></tr><tr><td>FootFaultScan</td><td>Clever Sys Inc.</td><td>-</td><td></td></tr><tr><td>Glass slide</td><td>CITOTEST Scientific</td><td>80302-2104</td><td></td></tr><tr><td>Hematoxylin and Eosin Staining Kit</td><td>Beyotime Biotechnology</td><td>C0105S</td><td></td></tr><tr><td>micro-grinding drill&amp;nbsp;</td><td>FEIYUBIO</td><td>19-7010</td><td></td></tr><tr><td>Mouse spinal fixator</td><td>RWD Life Science</td><td>68094</td><td></td></tr><tr><td>Paraffin microtome</td><td>Thermo</td><td>shandon finesse 325</td><td></td></tr><tr><td>RotaRod for Mice</td><td>Ugo Basile</td><td>47600</td><td></td></tr><tr><td>Stereomicroscope</td><td>KUY NICE</td><td>SZM-7045</td><td></td></tr><tr><td>Tert-Amyl alcohol</td><td>Macklin</td><td>75-85-4</td><td></td></tr><tr><td>Xylene</td><td>China National Pharmaceutical</td><td>#10023418</td><td></td></tr></tbody></table>

automated impactor for contusive spinal cord injury model in mice

Spinal cord injury (SCI) due to traumatic injuries such as car accidents and falls is associated with permanent spinal cord dysfunction. Creation of contusion models of spinal cord injury by impacting the spinal cord results in similar pathologies to most spinal cord injuries in clinical practice. Accurate, reproducible, and convenient animal models of spinal cord injury are essential for studying spinal cord injury. We present a novel automated spinal cord injury contusion device for mice, the Guangzhou Jinan University smart spinal cord injury system, that can produce spinal cord injury contusion models with accuracy, reproducibility, and convenience. The system accurately produces models of varying degrees of spinal cord injury via laser distance sensors combined with an automated mobile platform and advanced software. We used this system to create three levels of spinal cord injury mice models, determined their Basso mouse scale (BMS) scores, and performed behavioral as well as staining assays to demonstrate its accuracy and reproducibility. We show each step of the development of the injury models using this device, forming a standardized procedure. This method produces reproducible spinal cord injury contusion mice models and reduces human manipulation factors via convenient handling procedures. The developed animal model is reliable for studying spinal cord injury mechanisms and associated treatment approaches.

Laminectomy was performed on 24 female mice (8 weeks old) as described above. Mice in the sham group (n=6) were not subjected to spinal cord injury, while the rest of the mice, including 0.5 mm group (n=6), 0.8 mm group (n=6), and 1.1 mm group (n=6) were subjected to different depths of spinal cord impingement. The BMS scores were regularly recorded until 1 month postoperatively (Figure 4). There were significant differences in postoperative BMS scores of mice in different groups. After 1 mo...

Watch this Scientific Journal Video about Automated Impactor for Contusive Spinal Cord Injury Model in Mice at JoVE.com

Author Spotlight: Insight Into Innovations in Spinal Cord Injury Research

Presented here is a novel automated spinal cord injury contusion device for mice, which can accurately produce spinal cord injury contusion models with varying degrees.

Automated Impactor for Contusive Spinal Cord Injury Model in Mice

Spinal cord injury (SCI) due to traumatic injuries such as car accidents and falls is associated with permanent spinal cord dysfunction. Creation of ...

automated-impactor-for-contusive-spinal-cord-injury-model-in-mice

Research

JoVE Journal

Neuroscience

1.8K Views.  Jinan University. Presented here is a novel automated spinal cord injury contusion device for mice, which can accurately produce spinal cord injury contusion models with varying degrees.

Video: Author Spotlight: Insight Into Innovations in Spinal Cord Injury Research

A Contusive Model of Unilateral Cervical Spinal Cord Injury Using the Infinite Horizon Impactor

While the majority of human spinal cord injuries occur in the cervical spinal cord, the vast majority of laboratory research employs animal models of spinal cord injury (SCI) in which the thoracic spinal cord is injured. Additionally, because most human cord injuries occur as the result of blunt, non-penetrating trauma (e.g. motor vehicle accident, sporting injury) where the spinal cord is violently struck by displaced bone or soft tissues, the majority of SCI researchers are of the opinion that the most clinically relevant injury models are those in which the spinal cord is rapidly contused.1 Therefore, an important step in the preclinical evaluation of novel treatments on their way to human translation is an assessment of their efficacy in a model of contusion SCI within the cervical spinal cord. Here, we describe the technical aspects and resultant anatomical and behavioral outcomes of an unilateral contusive model of cervical SCI that employs the Infinite Horizon spinal cord injury impactor.
Sprague Dawley rats underwent a left-sided unilateral laminectomy at C5. To optimize the reproducibility of the biomechanical, functional, and histological outcomes of the injury model, we contused the spinal cords using an impact force of 150 kdyn, an impact trajectory of 22.5&deg; (animals rotated at 22.5&deg;), and an impact location off of midline of 1.4 mm. Functional recovery was assessed using the cylinder rearing test, horizontal ladder test, grooming test and modified Montoya's staircase test for up to 6 weeks, after which the spinal cords were evaluated histologically for white and grey matter sparing.
The injury model presented here imparts consistent and reproducible biomechanical forces to the spinal cord, an important feature of any experimental SCI model. This results in discrete histological damage to the lateral half of the spinal cord which is largely contained to the ipsilateral side of injury. The injury is well tolerated by the animals, but does result in functional deficits of the forelimb that are significant and sustained in the weeks following injury. The cervical unilateral injury model presented here may be a resource to researchers who wish to evaluate potentially promising therapies prior to human translation.

A reliable and repeatable way to produce a cervical unilateral spinal cord injury using the Infinite Horizon impactor is described. The method takes advantage of a custom designed frame and clamp to stabilize the spine. The standardized procedure and biomechanical injury parameters result in sufficient and sustained injuries.

While the majority of human spinal cord injuries occur in the cervical spinal cord, the vast majority of laboratory research employs animal models of ...

Medicine

A Contusion Model of Severe Spinal Cord Injury in Rats

The translational potential of novel treatments should be investigated in severe spinal cord injury (SCI) contusion models. A detailed methodology is described to obtain a consistent model of severe SCI. Use of a stereotactic frame and computer controlled impactor allows for creation of reproducible injury. Hypothermia and urinary tract infection pose significant challenges in the post-operative period. Careful monitoring of animals with daily weight recording and bladder expression allows for early detection of post-operative complications. The functional results of this contusion model are equivalent to transection models. The contusion model can be utilized to evaluate the efficacy of both neuroprotective and neuroregenerative approaches.

A contusion model of severe spinal cord injury is described. Detailed pre-operative, operative and post-operative steps are described to obtain a consistent model.

The translational potential of novel treatments should be investigated in severe spinal cord injury (SCI) contusion models. A detailed methodology is ...

Neural Stem Cell Transplantation in Experimental Contusive Model of Spinal Cord Injury

Spinal cord injury is a devastating clinical condition, characterized by a complex of neurological dysfunctions. Animal models of spinal cord injury can be used both to investigate the biological responses to injury and to test potential therapies. Contusion or compression injury delivered to the surgically exposed spinal cord are the most widely used models of the pathology. In this report the experimental contusion is performed by using the Infinite Horizon (IH) Impactor device, which allows the creation of a reproducible injury animal model through definition of specific injury parameters. Stem cell transplantation is commonly considered a potentially useful strategy for curing this debilitating condition. Numerous studies have evaluated the effects of transplanting a variety of stem cells. Here we demonstrate an adapted method for spinal cord injury followed by tail vein injection of cells in CD1 mice. In short, we provide procedures for: i) cell labeling with a vital tracer, ii) pre-operative care of mice, iii) execution of a contusive spinal cord injury, and iv) intravenous administration of post mortem neural precursors. This contusion model can be utilized to evaluate the efficacy and safety of stem cell transplantation in a regenerative medicine approach.

Spinal cord injury is a traumatic condition that causes severe morbidity and high mortality. In this work we describe in detail a contusion model of spinal cord injury in mice followed by a transplantation of neural stem cells.

Spinal cord injury is a devastating clinical condition, characterized by a complex of neurological dysfunctions. Animal models of spinal cord injury can ...

Calibrated Forceps Model of Spinal Cord Compression Injury

Compression injuries of the murine spinal cord are valuable animal models for the study of spinal cord injury (SCI) and spinal regenerative therapy. The calibrated forceps model of compression injury is a convenient, low cost, and very reproducible animal model for SCI. We used a pair of modified forceps in accordance with the method published by Plemel et al. (2008) to laterally compress the spinal cord to a distance of 0.35 mm. In this video, we will demonstrate a dorsal laminectomy to expose the spinal cord, followed by compression of the spinal cord with the modified forceps. In the video, we will also address issues related to the care of paraplegic laboratory animals. This injury model produces mice that exhibit impairment in sensation, as well as impaired hindlimb locomotor function. Furthermore, this method of injury produces consistent aberrations in the pathology of the SCI, as determined by immunohistochemical methods. After watching this video, viewers should be able to determine the necessary supplies and methods for producing SCI of various severities in the mouse for studies on SCI and/or treatments designed to mitigate impairment after injury.

Spinal cord injury models should be highly reproducible. We demonstrate that the calibrated forceps compression model of spinal cord injury is an easy to use surgical method for generating reproducible injuries to the murine spinal cord.

Compression injuries of the murine spinal cord are valuable animal models for the study of spinal cord injury (SCI) and spinal regenerative therapy. The ...

A Neonatal Mouse Spinal Cord Compression Injury Model

Spinal cord injury (SCI) typically causes devastating neurological deficits, particularly through damage to fibers descending from the brain to the spinal cord. A major current area of research is focused on the mechanisms of adaptive plasticity that underlie spontaneous or induced functional recovery following SCI. Spontaneous functional recovery is reported to be greater early in life, raising interesting questions about how adaptive plasticity changes as the spinal cord develops. To facilitate investigation of this dynamic, we have developed a SCI model in the neonatal mouse. The model has relevance for pediatric SCI, which is too little studied. Because neural plasticity in the adult involves some of the same mechanisms as neural plasticity in early life1, this model may potentially have some relevance also for adult SCI. Here we describe the entire procedure for generating a reproducible spinal cord compression (SCC) injury in the neonatal mouse as early as postnatal (P) day 1. SCC is achieved by performing a laminectomy at a given spinal level (here described at thoracic levels 9-11) and then using a modified Yasargil aneurysm mini-clip to rapidly compress and decompress the spinal cord. As previously described, the injured neonatal mice can be tested for behavioral deficits or sacrificed for ex vivo physiological analysis of synaptic connectivity using electrophysiological and high-throughput optical recording techniques1. Earlier and ongoing studies using behavioral and physiological assessment have demonstrated a dramatic, acute impairment of hindlimb motility followed by a complete functional recovery within 2 weeks, and the first evidence of changes in functional circuitry at the level of identified descending synaptic connections1.

This article describes a method for generating a reproducible spinal cord compression injury (SCI) in the neonatal mouse. The model provides an advantageous platform for studying mechanisms of adaptive plasticity that underlie spontaneous functional recovery.

Spinal cord injury (SCI) typically causes devastating neurological deficits, particularly through damage to fibers descending from the brain to the spinal ...

A Repetitive Concussive Head Injury Model in Mice

Despite the concussion/ mild traumatic brain injury (mTBI) being the most frequent occurrence of traumatic brain injury, there is still a lack of knowledge on the injury and its effects. To develop a better understanding of concussions, animals are often used because they provide a controlled, rigorous, and efficient model. Studies have adapted traditional animal models to perform mTBI to stimulate mild injury severity by changing the injury parameters. These models have been used because they can produce morphologically similar brain injuries to the clinical condition and provide a spectrum of injury severities. However, they are limited in their ability to present the identical features of injuries in patients. Using a traditional impact system, a repetitive concussive injury (rCHI) model can induce mild to moderate human-like concussion. The injury degree can be determined by measuring the period of loss of consciousness (LOC) with a sign of a transient termination of breathing. The rCHI model is beneficial to use for its accuracy and simplicity in determining mTBI effects and potential treatments.

Concussion presents the most common type of traumatic brain injury. Therefore, a repetitive concussive animal model, which replicates the important features of an injury in patients, may provide a means to study concussion in a rigorous, controlled, and efficient manner.

Despite the concussion/ mild traumatic brain injury (mTBI) being the most frequent occurrence of traumatic brain injury, there is still a lack of ...

A Tissue Displacement-based Contusive Spinal Cord Injury Model in Mice

Producing a consistent and reproducible contusive spinal cord injury (SCI) is critical to minimizing behavioral and histological variabilities between experimental animals. Several contusive SCI models have been developed to produce injuries using different mechanisms. The severity of the SCI is based on the height that a given weight is dropped, the injury force, or the spinal cord displacement. In the current study, we introduce a novel mouse contusive SCI device, the Louisville Injury System Apparatus (LISA) impactor, which can create a displacement-based SCI with high injury velocity and accuracy. This system utilizes laser distance sensors combined with advanced software to produce graded and highly-reproducible injuries. We performed a contusive SCI at the 10th thoracic vertebral (T10) level in mice to demonstrate the step-by-step procedure. The model can also be applied to the cervical and lumbar spinal levels.

We introduce a tissue displacement-based contusive spinal cord injury model that can produce a consistent contusive spinal cord injury in adult mice.

Producing a consistent and reproducible contusive spinal cord injury (SCI) is critical to minimizing behavioral and histological variabilities between ...

Murine Model of Controlled Cortical Impact for the Induction of Traumatic Brain Injury

The Centers for Disease Control and Injury Prevention estimate that almost 2 million people sustain a traumatic brain injury (TBI) every year in the United States. In fact, TBI is a contributing factor to over a third of all injury-related mortality. Nonetheless, the cellular and molecular mechanisms underlying the pathophysiology of TBI are poorly understood. Thus, preclinical models of TBI capable of replicating the injury mechanisms pertinent to TBI in human patients are a critical research need. The controlled cortical impact (CCI) model of TBI utilizes a mechanical device to directly impact the exposed cortex. While no model can full recapitulate the disparate injury patterns and heterogeneous nature of TBI in human patients, CCI is capable of inducing a wide range of clinically applicable TBI. Furthermore, CCI is easily standardized allowing investigators to compare results across experiments as well as across investigative groups. The following protocol is a detailed description of applying a severe CCI with a commercially available impacting device in a murine model of TBI.

Here we describe a protocol for the induction of murine traumatic brain injury via an open-head controlled cortical impact.

The Centers for Disease Control and Injury Prevention estimate that almost 2 million people sustain a traumatic brain injury (TBI) every year in the ...

Establishing a Mouse Contusion Spinal Cord Injury Model Based on a Minimally Invasive Technique

Using minimally invasive methods to model spinal cord injury (SCI) can minimize behavioral and histological differences between experimental animals, thereby improving the reproducibility of the experiments.
These methods need two requirements to be fulfilled: clarity of the surgical anatomical pathway and simplicity and convenience of the laboratory device. Crucially for the operator, a clear anatomical pathway provides minimally invasive exposure, which avoids additional damage to the experimental animal during the surgical procedures and allows the animal to maintain a consistent and stable anatomical morphology during the experiment.
In this study, the use of a novel integrated platform called the SCI coaxial platform for spinal cord injury in small animals to expose the T9 level spinal cord in a minimally invasive way and stabilize and immobilize the vertebra of mice using a vertebral stabilizer is researched, and, finally, a coaxial gravity impactor is used to contuse the spinal cord of mice to approach different degrees of T9 spinal cord injury. Finally, histological results are provided as a reference for the readers.

Minimally invasive techniques and a simple laboratory device improve the reproducibility of the spinal cord injury model by reducing operative damage to the experimental animals and allowing anatomical morphology maintenance. The method is worthwhile because the reliable results and reproducible procedure facilitate investigations of the mechanisms of disease reparation.

Using minimally invasive methods to model spinal cord injury (SCI) can minimize behavioral and histological differences between experimental animals, ...

Electromagnetic Controlled Closed-Head Model of Mild Traumatic Brain Injury in Mice

Highly reproducible animal models of traumatic brain injury (TBI), with well-defined pathologies, are needed for testing therapeutic interventions and understanding the mechanisms of how a TBI alters brain function. The availability of multiple animal models of TBI is necessary to model the different aspects and severities of TBI seen in people. This manuscript describes the use of a midline closed head injury (CHI) to develop a mouse model of mild TBI. The model is considered mild because it does not produce structural brain lesions based on neuroimaging or gross neuronal loss. However, a single impact creates enough pathology that cognitive impairment is measurable at least 1 month after injury. A step-by-step protocol to induce a CHI in mice using a stereotaxically guided electromagnetic impactor is defined in the paper. The benefits of the mild midline CHI model include the reproducibility of the injury-induced changes with low mortality. The model has been temporally characterized up to 1 year after the injury for neuroimaging, neurochemical, neuropathological, and behavioral changes. The model is complementary to open skull models of controlled cortical impact using the same impactor device. Thus, labs can model both mild diffuse TBI and focal moderate-to-severe TBI with the same impactor.

The protocol describes mild traumatic brain injury in a mouse model. In particular, a step-by-step protocol to induce a mild midline closed head injury and the characterization of the animal model is fully explained.

Highly reproducible animal models of traumatic brain injury (TBI), with well-defined pathologies, are needed for testing therapeutic interventions and ...