The authors wish to thank Gergely &#193;ngy&#225;n for the original artwork. This research work was funded by Semmelweis University, Budapest, Hungary. This study was also supported by the Hungarian Human Resources Development Operational Program (EFOP-3.6.2-16-2017-00006). Additional support was received from the Thematic Excellence Programme (2020-4.1.1.-TKP2020) of the Ministry for Innovation and Technology in Hungary, within the framework of the Therapy thematic program of Semmelweis University.

All animal procedures were carried out according to the EU Directive (2010/63/EU) and were approved by the animal ethics committee of the Hungarian National Food Chain Safety Office (PEI/001/2894-11/2014). All applicable institutional and governmental regulations concerning the ethical use of animals were followed during this study.
1. Preparation before surgery
<ol>
	<li>Sterilize all instruments used during the procedure (see the Table of Materials) and disinfect the surfaces where the work is to be performed prior to the procedure.</li>
	<li>Inject a single dose of subcutaneous antibiotics prophylactically. 
	NOTE: See the&#160;Table of Materials&#160;for antibiotic dosage details.</li>
	<li>Leave the animals in the operating room for 1 h to acclimate them and decrease their stress prior to surgery.</li>
	<li>Anesthetize the rat via an intramuscular injection of a combination of ketamine and xylazine (ketamine 80 mg/kg body weight (bw) and xylazine 8 mg/kg bw). 
	NOTE: In addition to anesthesia, the ketamine-xylazine combination&#160;provides&#160;sufficient&#160;analgesia for this procedure. The analgesia regimen&#160;can be modified per the institutional animal use guidelines.</li>
	<li>Keep the rat warm during the procedure using a heated table or infrared light and keep the eyes moist throughout the anesthesia using ophthalmic ointment&#160;(reapply as necessary).</li>
	<li>Fixate the animal on the operating table using surgical tape on its front and back paws and tail, and depending on the site of injury, on the neck as well. If necessary, place the rat in a stereotaxic frame to stabilize it during surgery.</li>
	<li>Using sterile surgical suture, place a loop around the upper front teeth of the rat and fixate this on the edge of the operating table.</li>
	<li>Pull out the tongue sideways for airway management.</li>
	<li>Shave the fur on the back, at least 2 cm in each direction of where the incision will be made.</li>
	<li>Disinfect the skin of the surgical area at least three times, using a povidone-iodine solution and sterile gauze. Take special care to soak the fur surrounding the area. Secure&#160;the surgical site with a sterile drape.&#160;</li>
	<li>Assess the adequacy of the anesthesia before placing the first incision by pinching the toes and the tail of the animal. Continue monitoring the adequacy of anesthesia during the entire procedure.</li>
</ol>
2. Surgery
<ol>
	<li>Place the skin incision using a scalpel blade 20. To open the surgical area, place a 2-2.5 cm long incision along the spine, cutting through all the layers of the skin. Position this incision parallel to the spinal column using the L1 vertebra as a midpoint, making it extend ~1 cm in both the cranial and caudal direction along the spinal column.</li>
	<li>Mobilize the sides of the wound by cutting through the connective tissue surrounding the muscles.</li>
	<li>Place two parallel incisions along the spine, penetrating the periosteum. Place the incisions right next to the spinal processes on both sides, spanning the distance between the Th13 and L1 vertebrae.</li>
	<li>Dissect the muscles attached to the vertebrae with the aid of a raspatorium until all the spinal ligaments are visible. Put in place a retractor.</li>
	<li>Remove the spinal processes of the 13th thoracic vertebra and the 1st lumbar vertebra using dental bone forceps to visualize the entire surgical area. Hereon, control the procedure by viewing an enlarged (4x-16x magnification) microscopic image.</li>
	<li>Use sterile gauze to control bleeding throughout the procedure, when necessary.</li>
	<li>Carefully lift the remainder of the L1 spinal processes, elevating the L1 vertebral arch. Sever the ligamentum flavum to access the spinal cord. Raise the caudal spinal processes further, allowing access to the spinal dura mater, which is also severed. Tip the caudal spinal processes in the cranial direction to visualize the pia mater.</li>
	<li>Look through the pia mater for the posterior median vein, showcasing the midline of the spine.</li>
	<li>Using the vein as a directional bisector, place an incision using a microsurgical scalpel while sparing the vein. Place the incision under the vein, in the transversal plane through the anteroposterior diameter of the spinal cord. Sever half of the spinal cord by moving the blade laterally away from the centerline. 
	NOTE: The incision is unilateral, on the right side, at the 4th lumbar segment.</li>
	<li>Try to place the incision to avoid cutting the anterior spinal artery. Ensure excess pressure is not applied on the vertebral body when cutting the spinal cord to spare the anterior spinal artery on the ventral side of the spinal cord.</li>
</ol>
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/63534/63534fig01.jpg" /> 
Figure 1: Artwork showing the steps of the new open SCI technique in rats. (A) The exposed vertebrae. (B) Spinal processes removed (Th13 and L1). (C) The lifted and tilted vertebral arch of the L1 vertebra. (D) Hemisection performed on the right side, with hemisected spinal cord shown separately, zoomed in. <a href="https://www.jove.com/files/ftp_upload/63534/63534fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol start="11">
	<li>Do not close the dura mater directly during wound closure. Tightly suture (suture size 4-0) the muscles along the spinal processes, indirectly closing the small wound on the dura mater.</li>
	<li>Close the dorsal connective tissue layer with sutures.</li>
	<li>Finally, suture the skin around the incision site.</li>
</ol>
3. Postsurgical care and follow-up
<ol>
	<li>Allow the animals to awaken in their cages. Keep the animal(s) warm using a heat lamp in addition to the temperature-controlled room. Do not leave the rats alone after they awaken after surgery, and do not put them together with other rats in the same cage.</li>
	<li>Monitor their respiratory rate at least every 10 min until they are fully awake. If necessary, apply gentle stimulation (e.g., rub the head) to aid their awakening from anesthesia.</li>
	<li>When the animals are alert and appropriately active, transport them safely back to the animal house.</li>
	<li>Keep the rats under close surveillance for the first 24 h post surgery. Following the first 24 h post surgery, check the animals at least twice a day until the end of the experiment, monitoring for signs of distress.</li>
	<li>Thoroughly assess them once a day for signs of distress using the relevant institutional animal welfare protocol and take special care to check their wounds for signs of infection and inflammation. 
	NOTE: Stress and infection affect the welfare of the animals and the outcome of experiments.</li>
	<li>Administer antibiotics subcutaneously&#160;every day until the end of the experiments. Keep the animals in sterile cages, one animal per cage, and give food and water ad libitum, same as before. At the end of the experiments (or if any serious adverse reaction is observed during the timeframe of the experiment), euthanize the animals humanely, in accordance with the relevant institutional animal welfare protocol. 
	NOTE: Here, the animals were euthanized (in a deep sleep induced by the combination of ketamine-xylazine) by first administering a physiological saline perfusion (1/3 mL/g bw) followed by a 4% paraformaldehyde perfusion (1 mL/g bw).</li>
</ol>

<ol>
	<li>Failli, V., 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=Functional+neurological+recovery+after+spinal+cord+injury+is+impaired+in+patients+with+infections.">Functional neurological recovery after spinal cord injury is impaired in patients with infections.</a> Brain. 135, 3238-3250 (2012).</li><li>Guan, B., Chen, R., Zhong, M., Liu, N., Chen, Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protective+effect+of+Oxymatrine+against+acute+spinal+cord+injury+in+rats+via+modulating+oxidative+stress,+inflammation+and+apoptosis.">Protective effect of Oxymatrine against acute spinal cord injury in rats via modulating oxidative stress, inflammation and apoptosis.</a> Metabolic Brain Disease. 35 (1), 149-157 (2020).</li><li>Kjell, J., Olson, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rat+models+of+spinal+cord+injury:+from+pathology+to+potential+therapies.">Rat models of spinal cord injury: from pathology to potential therapies.</a> Disease Models &amp; Mechanisms. 9 (10), 1125-1137 (2016).</li><li>Minakov, A. N., Chernov, A. S., Asutin, D. S., Konovalov, N. A., Telegin, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+models+of+spinal+cord+injury+in+laboratory+rats.">Experimental models of spinal cord injury in laboratory rats.</a> Acta Naturae. 10 (3), 4-10 (2018).</li><li>Borb&#233;ly, Z., 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=Effect+of+rat+spinal+cord+injury+(hemisection)+on+the+ex+vivo+uptake+and+release+of+[3H]noradrenaline+from+a+slice+preparation.">Effect of rat spinal cord injury (hemisection) on the ex vivo uptake and release of [3H]noradrenaline from a slice preparation.</a> Brain Research Bulletin. 131, 150-155 (2017).</li><li>Brown, A. R., Martinez, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thoracic+spinal+cord+hemisection+surgery+and+open-field+locomotor+assessment+in+the+rat.">Thoracic spinal cord hemisection surgery and open-field locomotor assessment in the rat.</a> Journal of Visualized Experiments: JoVE. (148), e59738 (2019).</li><li>Taoka, Y., Okajima, K. <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+in+the+rat.">Spinal cord injury in the rat.</a> Progress in Neurobiology. 56 (3), 341-358 (1998).</li><li>Hou, S., Saltos, T. M., Iredia, I. W., Tom, V. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surgical+techniques+influence+local+environment+of+injured+spinal+cord+and+cause+various+grafted+cell+survival+and+integration.">Surgical techniques influence local environment of injured spinal cord and cause various grafted cell survival and integration.</a> Journal of Neuroscience Methods. 293, 144-150 (2018).</li><li>Mattucci, 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=Development+of+a+traumatic+cervical+dislocation+spinal+cord+injury+model+with+residual+compression+in+the+rat.">Development of a traumatic cervical dislocation spinal cord injury model with residual compression in the rat.</a> Journal of Neuroscience Methods. 322, 58-70 (2019).</li><li>Ahmed, R. U., Alam, M., Zheng, Y. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+spinal+cord+injury+and+behavioral+tests+in+laboratory+rats.">Experimental spinal cord injury and behavioral tests in laboratory rats.</a> Heliyon. 5 (3), 01324 (2019).</li><li>Ashammakhi, N., 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=Regenerative+therapies+for+spinal+cord+injury.">Regenerative therapies for spinal cord injury.</a> Tissue Engineering. Part B, Reviews. 25 (6), 471-491 (2019).</li></ol>

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

This minimally invasive spinal cord injury technique was developed when studying spinal cord-injured rats, and the team was faced with problems arising from the surgery itself (bone splinters from the laminectomy causing compression and damaging the spinal cord, surgery taking too long, slow healing of a large bone wound). By eliminating the laminectomy, the procedure became much faster (11 min vs. 35 min), the structure of the vertebral canal remained intact, the bone wound was much smaller, and there were no bone splin...

Spinal cord injuries (SCIs) are unfortunately prevalent injuries in humans. SCIs can be complicated in different ways, for example, by infections, and it is clinically important to study these injuries1. Because there is no single, definite cure for SCIs, animal models are still needed to further the understanding of researchers and advance possible treatments2,3. Although closed injuries are most commonly modeled (compression and contusion), it is clinically important to understand lacerations, which can only be modeled in open injuries4. Open-wound models using transection or hemisection can be used to demonstrate a more precise localization of a wound compared to closed injury models, owing to the nature of the injury (contusion vs. surgical cut). Open-wound experiments can shed light on more specific neuronal injuries in a controlled, reliable, and replicable way5. The complete or partial transection of the spinal cord is a widely used open-wound technique and can be viewed in detail in the article by Brown and Martinez6.
When studying open spinal cord injury in rats, several animals presented problems that arose from the surgery: bone splinters from the laminectomy became embedded in the spinal cord and caused swelling; the larger bone wound needed a long time to heal; the surgery took too long. An alternate surgical technique was developed to eliminate these problems. The goal was to develop a faster technique that is gentler for the animal. This newly developed technique is much faster than traditional SCI techniques. The surgical approach is minimally invasive, resulting in a smaller bone wound while eliminating problems arising from the laminectomy.
All open-wound techniques involve opening the dura7. Several recent studies have examined different, newly developed techniques, aiming to improve the previous methods8,9. Even though the opening of the dura cannot be excluded using this new technique, it causes a smaller wound on the dura while offering a reliable, controlled injury of the spinal cord. Consulting the literature on spinal cord injury techniques, many authors tried to minimize the time of surgery by implementing minor changes to the original technique10. Laminectomy is always part of these surgical procedures, although it is time-consuming and requires a larger bone wound to be made6. This surgical technique can be appropriate for researchers using open wound spinal cord injury models, specifically complete transection or lateral hemisection performed in the intervertebral spaces (Figure 1).

<table><tbody><tr><td>Augmentin (1,000 mg/200 mg powder)</td><td>GlaxoSmithKline, UK</td><td></td><td>One-time dose of s.c. antibiotics prophylactically (10 mg of amoxicillin and 2 mg clavulanic acid; Augmentin 1,000 mg/200 mg powder). Every day following surgery, 10 mg of amoxicillin and 2 mg of clavulanic acid (Augmentin 1,000 mg/200 mg powder) per day per animal</td></tr><tr><td>Betadine</td><td>EGIS, Hungary</td><td></td><td>Disinfect the skin of the surgical area using a povidone-iodine solution</td></tr><tr><td>Calypsol (50 mg/mL)</td><td>Richter Gedeon, Hungary</td><td></td><td>&lt;strong&gt;Anesthesia: combination of ketamine 80 mg/kg and xylazine 8 mg/kg intramuscularly&lt;/strong&gt;</td></tr><tr><td>CP XYLAZIN 2% (20 mg/mL)</td><td>Produlab Pharma B.V., the Netherlands</td><td></td><td>&lt;strong&gt;Anesthesia: combination of ketamine 80 mg/kg and xylazine 8 mg/kg intramuscularly&lt;/strong&gt;</td></tr><tr><td>Dental bone forceps</td><td>Dentech, Hungary</td><td>BS 0127</td><td>Remove the spinous processes of the 13&lt;sup&gt;th&lt;/sup&gt; thoracic vertebra and the 1&lt;sup&gt;st&lt;/sup&gt; lumbar vertebra using dental bone forceps</td></tr><tr><td>dental surgical micromotor</td><td>W&amp;amp;H, Austria</td><td>MF-TECTORQUE</td><td>Using a dental surgical micromotor, a laminectomy is performed at the L1 vertebra</td></tr><tr><td>optical microscope</td><td>Zeiss, Germany</td><td>OPMI19-FC</td><td>Control the procedure by viewing an enlarged (16x magnification) microscopic image</td></tr><tr><td>physiological saline solution (0.9% NaCl)</td><td>Fresenius Kabi, Germany</td><td></td><td>Keep the rat&#039;s eyes moist throughout the entire anesthesia using physiological saline solution drops (reapply as necessary)</td></tr><tr><td>raspatorium</td><td>Dentech, Hungary</td><td>FK 1164</td><td>Dissect the muscles attached to the vertebrae with the aid of a raspatorium, until all the spinal ligaments are visible.</td></tr><tr><td>retractor</td><td>Dentech, Hungary</td><td>RT 1253</td><td></td></tr><tr><td>scalpel</td><td>Dentech, Hungary</td><td>BB 173</td><td></td></tr><tr><td>scalpel</td><td>Dentech, Hungary</td><td>BB 184</td><td></td></tr><tr><td>scalpel blade 12</td><td>B. Braun, Germany</td><td>12</td><td></td></tr><tr><td>scalpel blade 20</td><td>B. Braun, Germany</td><td>20</td><td></td></tr><tr><td>sterile cut gauze 10 x 10 cm</td><td>Sterilux, Hartmann, Germany</td><td></td><td></td></tr><tr><td>sutures (monofilament, synthetic; absorbable and nonabsorbable), size: 4-0</td><td>B. Braun, Germany</td><td></td><td></td></tr><tr><td>tweezer (13 cm)</td><td>Dentech, Hungary</td><td>BD 1555</td><td></td></tr><tr><td>tweezer (delicate tissue forceps)</td><td>Dentech, Hungary</td><td>BD 1670</td><td></td></tr></tbody></table>

a minimally invasive, fast spinal cord lateral hemisection technique for modeling open spinal cord injuries in rats

Open spinal cord injury techniques modeling laceration-like injuries are time-consuming and invasive because they involve laminectomy. This new technique eliminates laminectomy by removing two spinous processes and lifting, then tilting the caudal vertebral arch. The surgical area opens up without the need for laminectomy. Lateral hemisection is then performed with direct visible control under a microscope. The trauma is minimized, requiring only a small bone wound. 
This technique has several advantages: it is faster and, therefore, less of a burden for the animal, and the bone wound is smaller. Because the laminectomy is eliminated, there is less chance for unwanted injury to the spinal cord, and there are no bone splinters that can cause problems (bone splinters embedded in the spinal cord can cause swelling and secondary damage). The vertebral canal remains intact. The main limitation is that the hemisection can only be performed in the intervertebral spaces. 
The results show that this technique can be performed much faster than the traditional surgical approach, using laminectomy (11 min vs. 35 min). This technique can be useful for researchers working with animal models of open spinal cord injury as it is widely adaptable and does not require any additional specialized instrumentation.

Following the hemisection, the rats show paralysis in the ipsilateral hindlimb (in vivo proof of successful hemisection). Thorough specimen evaluation can only be done following the removal of the spinal cord (see Figure 2, where the removed spinal cord can be seen from both the ventral and dorsal sides).
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/63534/63534fig02.jpg" /> 
Figure 2...

Watch this Scientific Journal Video about A Minimally Invasive, Fast Spinal Cord Lateral Hemisection Technique for Modeling Open Spinal Cord Injuries in Rats at JoVE.com

A Minimally Invasive, Fast Spinal Cord Lateral Hemisection Technique for Modeling Open Spinal Cord Injuries in Rats

Here, we describe a new, fast technique modeling open spinal cord injury in rats that eliminates laminectomy. Lateral hemisection is performed while viewing through a microscope. The technique is versatile and can also be used in the cervical, thoracic, and lumbar regions of the spinal cord of other animals.

Open spinal cord injury techniques modeling laceration-like injuries are time-consuming and invasive because they involve laminectomy. This new technique ...

a-minimally-invasive-fast-spinal-cord-lateral-hemisection-technique

Research

JoVE Journal

Neuroscience

2.1K Views.  Semmelweis University. Here, we describe a new, fast technique modeling open spinal cord injury in rats that eliminates laminectomy. Lateral hemisection is performed while viewing through a microscope. The technique is versatile and can also be used in the cervical, thoracic, and lumbar regions of the spinal cord of other animals.

Video: A Minimally Invasive, Fast Spinal Cord Lateral Hemisection Technique for Modeling Open Spinal Cord Injuries in Rats

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

Using Laser Doppler Imaging and Monitoring to Analyze Spinal Cord Microcirculation in Rat

Laser Doppler flowmetry (LDF) is a noninvasive method for blood flow (BF) measurement, which makes it preferable for measuring microcirculatory alterations of the spinal cord. In this article, our goal was to use both Laser Doppler imaging and monitoring to analyze the change of BF after spinal cord injury. Both the laser Doppler image scanner and the probe/monitor were being employed to obtain each readout. The data of LDPI provided a local distribution of BF, which gave an overview of perfusion around the injury site and made it accessible for comparative analysis of BF among different locations. By intensely measuring the probing area over a period of time, a combined probe was used to simultaneously measure the BF and oxygen saturation of the spinal cord, showing overall spinal cord perfusion and oxygen supply. LDF itself has a few limitations, such as relative flux, sensitivity to movement, and biological zero signal. However, the technology has been applied in clinical and experimental study due to its simple setup and rapid measurement of BF.

Here we present a combination of laser Doppler perfusion imaging (LDPI) and laser Doppler perfusion monitoring (LDPM) to measure spinal cord local blood flows and oxygen saturation (SO2), as well as a standardized procedure for introducing spinal cord trauma on rat.

Laser Doppler flowmetry (LDF) is a noninvasive method for blood flow (BF) measurement, which makes it preferable for measuring microcirculatory ...

Behavior

Controlled Cervical Laceration Injury in Mice

Use of genetically modified mice enhances our understanding of molecular mechanisms underlying several neurological disorders such as a spinal cord injury (SCI). Freehand manual control used to produce a laceration model of SCI creates inconsistent injuries often associated with a crush or contusion component and, therefore, a novel technique was developed. Our model of cervical laceration SCI has resolved inherent difficulties with the freehand method by incorporating 1) cervical vertebral stabilization by vertebral facet fixation, 2) enhanced spinal cord exposure, and 3) creation of a reproducible laceration of the spinal cord using an oscillating blade with an accuracy of &plusmn;0.01 mm in depth without associated contusion. Compared to the standard methods of creating a SCI laceration such as freehand use of a scalpel or scissors, our method has produced a consistent lesion. This method is useful for studies on axonal regeneration of corticospinal, rubrospinal, and dorsal ascending tracts.

A novel technique to create a reproducible in vivo model of cervical spinal cord laceration injury in the mouse is described. This technique is based on spine stabilization by fixation of the cervical facets and laceration of the spinal cord using an oscillating blade with an accuracy of &plusmn;0.01 mm.

Use of genetically modified mice enhances our  understanding of molecular mechanisms underlying several neurological disorders  such as a spinal cord ...

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 ...

Combining Peripheral Nerve Grafting and Matrix Modulation to Repair the Injured Rat Spinal Cord

Traumatic injury to the spinal cord (SCI) causes death of neurons, disruption of motor and sensory nerve fiber (axon) pathways and disruption of communication with the brain. One of the goals of our research is to promote axon regeneration to restore connectivity across the lesion site. To accomplish this we developed a peripheral nerve (PN) grafting technique where segments of sciatic nerve are either placed directly between the damaged ends of the spinal cord or are used to form a bridge across the lesion. There are several advantages to this approach compared to transplantation of other neural tissues; regenerating axons can be directed towards a specific target area, the number and source of regenerating axons is easily determined by tracing techniques, the graft can be used for electrophysiological experiments to measure functional recovery associated with axons in the graft, and it is possible to use an autologous nerve to reduce the possibility of graft rejection. In our lab we have performed both autologous (donor and recipient are the same animal) and heterologous (donor and recipient are different animals) grafts with comparable results. This approach has been used successfully in both acute and chronic injury situations. Regenerated axons that reach the distal end of the PN graft often fail to extend back into the spinal cord, so we use microinjections of chondroitinase to degrade inhibitory molecules associated with the scar tissue surrounding the area of SCI. At the same time we have found that providing exogenous growth and trophic molecules encourages longer distance axonal regrowth into the spinal cord. Several months after transplantation we perform a variety of anatomical, behavioral and electrophysiological tests to evaluate the recovery of function in our spinal cord injured animals. This experimental approach has been used successfully in several spinal cord injury models, at different levels of injury and in different species (mouse, rat and cat). Importantly, the peripheral nerve grafting approach is effective in promoting regeneration by acute and chronically injured neurons.

Traumatic injury to the spinal cord disrupts communication with the brain. To restore lost connectivity we utilize a peripheral nerve graft to provide a substratum for regenerating fibers in combination with neurotrophic factors and matrix-modulating enzymes to remove inhibitory molecules to promote long distance growth.

Traumatic injury to the spinal cord (SCI) causes death of neurons, disruption of motor and sensory nerve fiber (axon) pathways and disruption of ...

Biology

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 ...

Spinal Cord Lateral Hemisection and Asymmetric Behavioral Assessments in Adult Rats

Incomplete spinal cord injury (SCI) often leads to impairments of sensorimotor functions and is clinically the most frequent type of SCI. Human Brown-S&#233;quard syndrome&#160;is a common type of incomplete SCI caused by a lesion to one half of the spinal cord which results in paralysis and loss of&#160;proprioception&#160;on the same (or ipsilesional) side as the injury, and loss of pain and temperature sensation on the opposite (or contralesional) side. Adequate methodologies for producing a spinal cord lateral hemisection (HX) and assessing neurological impairments are essential to establish a reliable animal model of Brown-S&#233;quard syndrome. Although lateral hemisection model plays a pivotal role in basic and translational research, standardized protocols for creating such a hemisection and assessing unilateralized function are lacking. The goal of this study is to describe step-by-step procedures to produce a rat spinal lateral HX at the 9th thoracic (T9) vertebral level. We, then, describe a combined behavior scale for HX (CBS-HX) that provides a simple and sensitive assessment of asymmetric neurological performance for unilateral SCI. The CBS-HX, ranging from 0 to 18, is composed of 4 individual assessments which include unilateral hindlimb stepping (UHS), coupling, contact placing, and grid walking. For CBS-HX, the ipsilateral and contralateral hindlimbs are assessed separately. We found that, after a T9 HX, the ipsilateral hindlimb showed impaired behavior function whereas the contralateral hindlimb showed substantial recovery. The CBS-HX effectively discriminated behavioral functions between ipsilateral and contralateral hindlimbs and detected temporal progression of recovery of the ipsilateral hindlimb. The CBS-HX components can be analyzed separately or in combination with other measures when needed. Although we only provided visual descriptions of the surgical procedures and behavioral assessments of a thoracic HX, the principle may be applied to other incomplete SCIs and at other levels of the injury.

Here we describe surgical procedures to produce a reliable spinal cord lateral hemisection (HX) at the 9th thoracic level in adult rats and neurobehavioral assessments designed for detecting asymmetric deficits after such a unilateral injury.

Incomplete spinal cord injury (SCI) often leads to impairments of sensorimotor functions and is clinically the most frequent type of SCI. Human ...

Thoracic Spinal Cord Hemisection Surgery and Open-Field Locomotor Assessment in the Rat

Spinal cord injury (SCI) causes disturbances in motor, sensory, and autonomic function below the level of the lesion. Experimental animal models are valuable tools to understand the neural mechanisms involved in locomotor recovery after SCI and to design therapies for clinical populations. There are several experimental SCI models including contusion, compression, and transection injuries that are used in a wide variety of species. A hemisection involves the unilateral transection of the spinal cord and disrupts all ascending and descending tracts on one side only. Spinal hemisection produces a highly selective and reproducible injury in comparison to contusion or compression techniques that is useful for investigating neural plasticity in spared and damaged pathways associated with functional recovery. We present a detailed step-by-step protocol for performing a thoracic hemisection at the T8 vertebral level in the rat that results in an initial paralysis of the hindlimb on the side of the lesion with graded spontaneous recovery of locomotor function over several weeks. We also provide a locomotor scoring protocol to assess functional recovery in the open-field. The locomotor assessment provides a linear recovery profile and can be performed both early and repeatedly after injury in order to accurately screen animals for appropriate time points in which to conduct more specialized behavioral testing. The hemisection technique presented can be readily adapted to other transection models and species, and the locomotor assessment can be used in a variety of SCI and other injury models to score locomotor function.

The rat thoracic spinal hemisection is a valuable and reproducible model of unilateral spinal cord injury to investigate the neural mechanisms of locomotor recovery and treatment efficacy. This article includes a detailed step-by-step guide to perform the hemisection procedure and to assess locomotor performance in an open-field arena.

Spinal cord injury (SCI) causes disturbances in motor, sensory, and autonomic function below the level of the lesion. Experimental animal models are ...

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, ...

Performing Thoracic Spinal Cord Hemisection Surgery in Rats

Source: Brown, A. R., et al., <a href="https://app.jove.com/v/59738">Thoracic Spinal Cord Hemisection Surgery and Open-Field Locomotor Assessment in the Rat.</a>&#160;J. Vis. Exp.&#160;(2019).
This video demonstrates the surgical procedure for performing a thoracic spinal cord hemisection in rats. It outlines the steps to expose the T8 spinal cord segment, perform the hemisection to disrupt neural tracts on one side, and provide post-operative care.

Source: Brown, A. R., et al., Thoracic Spinal Cord Hemisection Surgery and Open-Field Locomotor Assessment in the Rat.&#160;J. Vis. Exp.&#160;(2019).
This ...