Name: controlled semi-automated laser-induced injuries for studying spinal cord regeneration in zebrafish larvae
Uploaded: 2021-11-22T15:00:00
Description: Watch this Scientific Journal Video about Controlled Semi-Automated Laser-Induced Injuries for Studying Spinal Cord Regeneration in Zebrafish Larvae at JoVE.com

This study was supported by the BBSRC (BB/S0001778/1). CR is funded by the Princess Royal TENOVUS Scotland Medical Research Scholarship Programme. We thank David Greenald (CRH, University of Edinburgh) and Katy Reid (CDBS, University of Edinburgh) for the kind gift of transgenic fish (See Supplementary File). We thank Daniel Soong (CRH, University of Edinburgh) for the kind access to the 3i spinning-disk confocal.

All animal studies were carried out with approval from the UK Home Office and according to its regulations, under project license PP8160052. The project was approved by the University of Edinburgh Institutional Animal Care and Use Committee. For experimental analyses, zebrafish larvae up to 5-day-old of either sex were used of the following available transgenic lines: Tg(Xla.Tubb:DsRed;mpeg1:GFP), Tg(Xla.Tubb:DsRed), Tg(betaactin:utrophin-mCherry), Tg(Xla.Tubb:GCaMP6s), and Tg(mnx1:gfp) (see Supplementary File 1<...

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There is an urgent need for a deeper understanding of the processes at play during regeneration in zebrafish. This animal model offers many benefits for biomedical research, in particular for spinal cord injuries1. Most of the studies involve manual lesions that require a well-trained operator and induce multi-tissue damage. A laser lesion protocol is presented here, allowing control over the lesion characteristics and reduced damage to the surrounding tissues. Furthermore, this technique is easy ...

An erratum was issued for:&#160;<a href="https://www.jove.com/t/63259">Controlled Semi-Automated Lased-Induced Injuries for Studying Spinal Cord Regeneration in Zebrafish Larvae</a>. The title was&#160;updated.
The title was updated from:
Controlled Semi-Automated Lased-Induced Injuries for Studying Spinal Cord Regeneration in Zebrafish Larvae
to:
Controlled Semi-Automated Laser-Induced Injuries for Studying Spinal Cord Regeneration in Zebrafish Larvae

An erratum was issued for:&#160;<a href="https://www.jove.com/t/63259">Controlled Semi-Automated Lased-Induced Injuries for Studying Spinal Cord Regeneration in Zebrafish Larvae</a>. The Title was&#160;updated.

Erratum:Controlled Semi-Automated Laser-Induced Injuries for Studying Spinal Cord Regeneration in Zebrafish Larvae

In contrast to mammals, zebrafish (Danio rerio) can repair their central nervous system (CNS) after injury1. The use of zebrafish larvae as a model for spinal cord regeneration is relatively recent. It has proven valuable to investigate the cellular and molecular mechanisms underlying repair2. This is due to the ease of manipulation, the short experimental cycle (new larvae every week), the tissues&#39; optical transparency, and the larvae&#39;s small size, ideally suited for in vivo fluorescence microscopy.
In the case of spinal cord regeneration, two additional advantages of using larvae are the speed of recovery, a few days compared to a few weeks for adults, and the ease of inducing injuries using manual techniques. This has been successfully used in many studies3,4,5, including recent investigations6,7. Overall, this leads to increased meaningful data production, high adaptability of experimental protocols, and decreased experimental costs. The use of larvae younger than 5 days post-fertilization also reduces the use of animals following the 3R principles in animal research8.
After a spinal cord injury in zebrafish larvae, many biological processes occur, including inflammatory response, cell proliferation, neurogenesis, migration of surviving or newly generated cells, reformation of functional axons, and a global remodeling of neural processes circuits and spine tissues6,7,9,10. To be successfully orchestrated, these processes involve a finely regulated interaction between a range of cell types, extracellular matrix components, and biochemical signals11,12. Unraveling the details of this significant reorganization of a complex tissue such as the spinal cord requires the use and development of precise and controlled experimental approaches.
The primary experimental paradigm used to study spinal cord regeneration in zebrafish is to use surgical means to induce tissue damage by resection, stabbing, or cryoinjury3,13. These approaches have the disadvantage of requiring specific training in microsurgery skills, which is time-consuming for any new operator and may prevent their use in short-term projects. Furthermore, they usually induce damage to the surrounding tissues, which may influence regeneration.
Another approach is to induce cell damage chemically14 or by genetic manipulations15. The latter allows for highly targeted damage. However, such a technique requires long preparatory work to generate new transgenic fish before doing any experiment, renewed each time a unique cell type is targeted.
There is, thus, the need for a method allowing targeted but versatile lesions suitable to a variety of studies in regeneration. A solution is to use a laser to induce localized damage in the tissue of interest16,17,18,19,20. Indeed, the use of laser-induced tissue damage presents a robust approach for generating spinal cord lesions with many advantages. The microscopes equipped with such laser manipulation modules allow specifying a customized shaped area where cell ablation will occur, with the extra benefit of temporal control. The size and position of the lesion can be thus adapted to address any questions.
The missing feature of most laser lesion systems is the possibility to induce injuries in a highly reproducible way for a series of larvae. Here an original protocol is described using a UV laser to induce semi-automated precise and controlled lesions in zebrafish larvae based on a microfluidic platform designed for automated larvae handling21. Moreover, in the system presented here, larvae are inserted in a glass capillary, which permits free rotation of the animal around its rostrocaudal axis. The user can choose which side of the larva to present to the laser while allowing fluorescence imaging to precisely target the laser beam and assess the damage after the lesion.
The protocol described here is used with a semi-automated zebrafish larvae imaging system combined with a spinning disk equipped with a UV laser (designated hereafter as the VAST system). However, the main points of the protocol and most of the claims of the technique are valid for any system equipped with a laser capable of cell ablation, including two-photon laser scanning microscopes, spinning-disk microscopes provided with a UV laser (FRAP module), or video-microscopes with a laser module for photo manipulation. One of the main differences between the VAST system and conventional sample handling will be that for the latter, mounting larvae in low-melting-point agarose on glass coverslips/glass-bottom Petri dishes in place of loading them in a 96-well plate will be required.
The benefits offered by this method open opportunities for innovative research on the cellular and molecular mechanisms during the regeneration process. Moreover, the high data quality allows for quantitative investigations in a multidisciplinary context.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Software</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Microscope software Zen Blue 2.0</td>
			<td>Carl Zeiss</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>ImageJ/FIJI</td>
			<td>Open-Source</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Visual Studio Code</td>
			<td>Microsoft</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Microscope and accessories</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>ApoTome microscope</td>
			<td>Carl Zeiss</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>C-Plan-Apochromat 10X (0.5NA) dipping lens</td>
			<td>Carl Zeiss</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>dual AxioCam 506 m CCD cameras</td>
			<td>Carl Zeiss</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Laser scanning confocal microscope LSM880</td>
			<td>Carl Zeiss</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Spinning-disk module CSU-X1</td>
			<td>Yokogawa</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Upright microscopeAxio Examiner D1</td>
			<td>Carl Zeiss</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>UV laser</td>
			<td>Micropoint</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>VAST BioImager</td>
			<td>Union Biometrica</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Labware</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>90 mm Petri dish</td>
			<td>Thermo-Fisher</td>
			<td>101R20</td>
			<td></td>
		</tr>
		<tr>
			<td>96-well plate</td>
			<td>Corning</td>
			<td>3841</td>
			<td></td>
		</tr>
		<tr>
			<td>Chemicals</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Click-It EdU Imaging Kit</td>
			<td>Invitrogen</td>
			<td>C10637</td>
			<td></td>
		</tr>
		<tr>
			<td>aminobenzoic-acid-ethyl methyl-ester (MS222)</td>
			<td>Sigma-Aldrich</td>
			<td>A5040</td>
			<td></td>
		</tr>
		<tr>
			<td>phenylthiourea (PTU)</td>
			<td>Sigma-Aldrich</td>
			<td>P7629</td>
			<td></td>
		</tr>
		<tr>
			<td>Antibodies</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Donkey anti-chicken Alexa Fluor 488</td>
			<td>Jackson</td>
			<td>703-545-155</td>
			<td></td>
		</tr>
		<tr>
			<td>Donkey anti-mouse Cy3</td>
			<td>Jackson</td>
			<td>715-165-150</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse anti-GFP</td>
			<td>Abcam</td>
			<td>AB13970</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse anti-tubulin acetylated antibody</td>
			<td>Sigma</td>
			<td>T6793</td>
			<td></td>
		</tr>
		<tr>
			<td>Transgenic zebrafish lines</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Tg(beta-actin:utrophin-mCherry)</td>
			<td></td>
			<td>N/A</td>
			<td>Established by David Greenhald, University of Edinburgh</td>
		</tr>
		<tr>
			<td>Tg(mnx1:gfp)</td>
			<td></td>
			<td>N/A</td>
			<td>First described in [Flanagan-Steet et al. 2005]</td>
		</tr>
		<tr>
			<td>Tg(Xla.Tubb:DsRed)</td>
			<td></td>
			<td>N/A</td>
			<td>First described in [Peri and Nusslein-Volhard 2008]</td>
		</tr>
		<tr>
			<td>Tg(Xla.Tubb:DsRed;mpeg1:GFP)</td>
			<td></td>
			<td>N/A</td>
			<td>Established by Katy Reid, University of Edinburgh</td>
		</tr>
		<tr>
			<td>Tg(Xla.Tubb:GCaMP6s)</td>
			<td></td>
			<td>N/A</td>
			<td>Established by David Greenhald, University of Edinburgh</td>
		</tr>
	</tbody>
</table>

controlled semi-automated laser-induced injuries for studying spinal cord regeneration in zebrafish larvae

Zebrafish larvae possess a fully functional central nervous system (CNS) with a high regenerative capacity only a few days after fertilization. This makes this animal model very useful for studying spinal cord injury and regeneration. The standard protocol for inducing such lesions is to transect the dorsal part of the trunk manually. However, this technique requires extensive training and damages additional tissues. A protocol was developed for laser-induced lesions to circumvent these limitations, allowing for high reproducibility and completeness of spinal cord transection over many animals and between different sessions, even for an untrained operator. Furthermore, tissue damage is mainly limited to the spinal cord itself, reducing confounding effects from injuring different tissues, e.g., skin, muscle, and CNS. Moreover, hemi-lesions of the spinal cord are possible. Improved preservation of tissue integrity after laser injury facilitates further dissections needed for additional analyses, such as electrophysiology. Hence, this method offers precise control of the injury extent that is unachievable manually. This allows for new experimental paradigms in this powerful model in the future.

Validation of spinal cord transection 
Structural and functional investigations were performed to assess whether the protocol allows a complete spinal cord transection.
First, to verify that the loss in fluorescence at the lesion site was due to neuronal tissue damage and not fluorescence photobleaching from the laser illumination, immunostaining using an antibody against acetylated tubulin (see Table of Materials and Supplementary File 1...

Watch this Scientific Journal Video about Controlled Semi-Automated Laser-Induced Injuries for Studying Spinal Cord Regeneration in Zebrafish Larvae at JoVE.com

Controlled Semi-Automated Laser-Induced Injuries for Studying Spinal Cord Regeneration in Zebrafish Larvae

The present protocol describes a method to induce tissue-specific and highly reproducible injuries in zebrafish larvae using a laser lesion system combined with an automated microfluidic platform for larvae handling.

Zebrafish larvae possess a fully functional central nervous system (CNS) with a high regenerative capacity only a few days after fertilization. This makes ...

The technique we propose here allows us to overcome the limitations of manual lesions protocols by reducing damage to adjacent tissues and improving reproducibility, even for inexperienced operators. This technique allows us to choose precisely where to induce the lesion without damaging surrounding tissues thanks to rotating glass capillary combined with a targeted UV laser. Many steps are involved in operating the VAST equipment, so I would recommend ticking off every step as you go in order to ensure everything is done correctly.Begin by anesthetizing the larvae using the medium containing the anesthetic, and then transfer them to a 96-well plate containing 300 microliters of medium per well. Switch on all the system components including the laser for ablation. Then, launch the automated zebrafish imaging, or VAST software, choose Plate on the first window, and click on the Done button.A small window will pop up asking whether the capillary is empty and clean. Check the image of the capillary for any air bubbles inside. If there are no air bubbles inside, click on Yes on the popped-up window.Next in the LP Sampler window, go to the File menu and select the Open script option. Choose a file containing the script corresponding to the experiment to be performed. Then, in the main VAST software window, go to File and choose Open experiment.Choose the experiment file corresponding to the planned experiment. Launch ImageJ/Fiji software, go to the File menu, and choose New script to open the script window. Then, go to the File menu and choose Open to load the laser lesion script.Next, to launch the Python IDE, go to the File menu and choose Open file to load the script to manage the laser. Then, click on the Run menu and choose Run Without Debugging to run the script. Ensure that a sequence of messages in the terminal panel appears along with some noise while the laser attenuator initializes.In the main window of the VAST software, click on the arrow buttons to move the stage and center the capillary relative to the microscope objective. Look through the eyepieces and focus on the top of the capillary using the transmitted light of the microscope. Place a 96-well plate containing the larvae on the left plate holder of the LP sampler.Then, place another plate for collection on the right plate holder of the sampler. Ensure that the A1 well of the plate is in the front left corner of the holder. In the LP Sampler window of the VAST software, click on the Plate template button and select all the wells containing larvae.Click on the OK button to validate and close the window. Then, click on the Run plate button in the LP Sampler window to start loading the larva. Next, go to the microscope software and click on the Live button to image the larva.Turn the microscope focus knob on until the spinal cord central canal is visible. Take a snapshot in fluorescence and save the image to a folder. Open the image in ImageJ and adjust the contrast if required.Click on the region-of-interest line tool and draw a short line centered on the spinal cord. Switch the microscope to 100%reflective mirror position. Load the ImageJ script and set Repetition to 2, Sample to 1, Width to 40 micron, and Attenuation to 89.After setting all the parameters, click on the OK button. When the laser shot sequence is finished, switch to fluorescence imaging on the imaging software and adjust the focus. Take a new snapshot and save it.Open this new image in ImageJ and draw a new line larger than the spinal cord itself. Switch the microscope to 100%reflective mirror position. Go to the ImageJ script window and set Repetition to 2, Sample to 1, Width to 40 microns, and Attenuation to 89.After setting all the parameters, click on the OK button. When the laser shot sequence is finished, verify the transection quality by imaging fluorescence and focusing. Ensure that no cells or axons remain intact in the lesion site.Go to the main VAST software window and click on the Collect button to collect the lesioned larvae into the empty 96-well plate. Then, click on the checkbox tray light to switch back on the VAST system light. Take out the larva from the 96-well plate as soon as possible, and transfer them to a clean Petri dish with fresh fish water for the larva to recover post-lesion.Put the Petri dish in an incubator at 28 degrees Celsius. Acetylated tubulin immuno-staining and calcium imaging indicate that laser lesion entirely disrupts the continuity of spinal tissue. An intact spinal cord is shown in this image.A complete disruption of the axons between the caudal and rostral sides of the lesion confirms the complete transection of the spinal cord. An example of incomplete transection is shown here. The transected spinal cord on an NBTG cAMP 6-S larva is shown in this image.The rectangles show the ROIs used to quantify the fluorescence intensity in the lesions'rostral and caudal sides. The graphical image represents the fluorescence intensity change over time in the rostral and caudal analysis ROIs. The maximum intensity projection fluorescence images of an NBT:dsRed larva before the laser lesion, after three hours, 24 hours, and 48 hours of the laser lesion are shown here.After 24 hours post-injury, the wounds started to close, leading to a partial restoration of the initial structure of the spinal cord after 48 hours. A partial functional reconnection was confirmed after 48 hours post-injury using calcium imaging. The ratio between the amplitude of the spikes in the caudal area and the rostral area showed an increase between 3, 24, and 48 hours post-injury.Macrophage recruitment was observed after laser lesions using NBT:dsRed mpeg1 GFP larvae laser lesions. No difference was observed in the number of labeled cells between manual and laser lesions. Unlesioned fish displayed fewer double-labeled cells than lesioned fish in both lesion conditions.Laser lesion induces less muscle and skin damage than manual lesion. It is critical to verify whether the lesion is complete or not. No intact cell or structure should be visible in the lesion area, only a dim background.To study spinal cord regeneration, we use many methods, including immuno-histochemistry and calcium imaging. Importantly, we can also do electrophysiology, as the tissue can withstand dissection, contrary to manually-lesioned animals. This new technique allows us to quantitatively study the structural and functional tissue organization in the spinal cord after injury by allowing reproducible and controlled lesions.

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Research

JoVE Journal

Medicine

Acute and Chronic Tactile Sensory Testing after Spinal Cord Injury in Rats

Spinal cord injury (SCI) impairs sensory systems causing allodynia1-8. To identify cellular and molecular causes of allodynia, sensitive and valid sensory testing in rat SCI models is needed. However, until recently, no single testing approach had been validated for SCI so that standardized methods have not been implemented across labs. Additionally, available testing methods could not be implemented acutely or when severe motor impairments existed, preventing studies of the development of SCI-induced allodynia3. Here we present two validated sensory testing methods using von Frey Hair (VFH) monofilaments which quantify changes in tactile sensory thresholds after SCI4-5. One test is the well-established Up-Down test which demonstrates high sensitivity and specificity across different SCI severities when tested chronically5. The other test is a newly-developed dorsal VFH test that can be applied acutely after SCI when allodynia develops, prior to motor recovery4-5. Each VFH monofilament applies a calibrated force when touched to the skin of the hind paw until it bends. In the up-down method, alternating VFHs of higher or lower forces are used on the plantar L5 dermatome to delineate flexor withdrawal thresholds. Successively higher forces are applied until withdrawal occurs then lower force VFHs are used until withdrawal ceases. The tactile threshold reflects the force required to elicit withdrawal in 50% of the stimuli. For the new test, each VFH is applied to the dorsal L5 dermatome of the paw while the rat is supported by the examiner. The VFH stimulation occurs in ascending order of force until at least 2 of 3 applications at a given force produces paw withdrawal. Tactile sensory threshold is the lowest force to elicit withdrawal 66% of the time. Acclimation, testing and scoring procedures are described. Aberrant trials that require a retest and typical trials are defined. Animal use was approved by Ohio State University Animal Care and Use Committee.

We describe two tactile sensory testing methods for acute or chronic periods of spinal cord injury in rats. These validated procedures can detect the development and maintenance of allodynia-like sensations.

Spinal cord injury (SCI) impairs sensory systems causing allodynia1-8. To identify cellular and molecular causes of allodynia, sensitive and valid sensory ...

Surgical Technique for Spinal Cord Delivery of Therapies: Demonstration of Procedure in Gottingen Minipigs

This is a compact visual description of a combination of surgical technique and device for the delivery of (gene and cell) therapies into the spinal cord. While the technique is demonstrated in the animal, the procedure is FDA-approved and currently being used for stem cell transplantation into the spinal cords of patients with ALS. While the FDA has recognized proof-of-principle data on therapeutic efficacy in highly characterized rodent models, the use of large animals is considered critical for validating the combination of a surgical procedure, a device, and the safety of a final therapy for human use. The size, anatomy, and general vulnerability of the spine and spinal cord of the swine are recognized to better model the human. Moreover, the surgical process of exposing and manipulating the spinal cord as well as closing the wound in the pig is virtually indistinguishable from the human. We believe that the healthy pig model represents a critical first step in the study of procedural safety.

Short visual description of the surgical technique and device used for the delivery of (gene and cell) therapies into the spinal cord. The technique is demonstrated in the animal but is entirely translatable and currently being used for human application.

This is a  compact visual description of a combination of surgical technique and device  for the  delivery of (gene and cell) therapies into the spinal ...

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 ...

Implanting Glass Spinal Cord Windows in Adult Mice with Experimental Autoimmune Encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) in adult rodents is the standard experimental model for studying autonomic demyelinating diseases such as multiple sclerosis. Here we present a low-cost and reproducible glass window implantation protocol that is suitable for intravital microscopy and studying the dynamics of spinal cord cytoarchitecture with subcellular resolution in live adult mice with EAE. Briefly, we surgically expose the vertebrae T12-L2 and construct a chamber around the exposed vertebrae using a combination of cyanoacrylate and dental cement. A laminectomy is performed from T13 to L1, and a thin layer of transparent silicone elastomer is applied to the dorsal surface of the exposed spinal cord. A modified glass cover slip is implanted over the exposed spinal cord taking care that the glass does not directly contact the spinal cord. To reduce the infiltration of inflammatory cells between the window and spinal cord, anti-inflammatory treatment is administered every 2 days (as recommended by ethics committee) for the first 10 days after implantation. EAE is induced only 2-3 weeks after the cessation of anti-inflammatory treatment.
Using this approach we successfully induced EAE in 87% of animals with implanted windows and, using Thy1-CFP-23 mice (blue axons in dorsal spinal cord), quantified axonal loss throughout EAE progression. Taken together, this protocol may be useful for studying the recruitment of various cell populations as well as their interaction dynamics, with subcellular resolution and for extended periods of time. This intravital imaging modality represents a valuable tool for developing therapeutic strategies to treat autoimmune demyelinating diseases such as EAE.

We describe a method for implanting and maintaining glass windows over the exposed spinal cords of adult mice for studying experimental autoimmune encephalomyelitis. These windows provide chronic optical access to the spinal cord for monitoring cell dynamics at the subcellular level in live animals using two-photon microscopy.

Experimental autoimmune encephalomyelitis (EAE) in adult rodents is the standard experimental model for studying autonomic demyelinating diseases such as ...

Controlled Cortical Impact Model for Traumatic Brain Injury

Every year over a million Americans suffer a traumatic brain injury (TBI). Combined with the incidence of TBIs worldwide, the physical, emotional, social, and economical effects are staggering. Therefore, further research into the effects of TBI and effective treatments is necessary. The controlled cortical impact (CCI) model induces traumatic brain injuries ranging from mild to severe. This method uses a rigid impactor to deliver mechanical energy to an intact dura exposed following a craniectomy. Impact is made under precise parameters at a set velocity to achieve a pre-determined deformation depth. Although other TBI models, such as weight drop and fluid percussion, exist, CCI is more accurate, easier to control, and most importantly, produces traumatic brain injuries similar to those seen in humans. However, no TBI model is currently able to reproduce pathological changes identical to those seen in human patients. The CCI model allows investigation into the short-term and long-term effects of TBI, such as neuronal death, memory deficits, and cerebral edema, as well as potential therapeutic treatments for TBI.

Traumatic brain injuries (TBIs) remain a serious health problem. Using the controlled cortical impact surgery model, research on the effects of TBI and possible treatment methods may be performed.

Every year over a million Americans suffer a traumatic brain injury (TBI).  Combined with the incidence of TBIs worldwide, the physical, emotional, ...

A Radio-telemetric System to Monitor Cardiovascular Function in Rats with Spinal Cord Transection and Embryonic Neural Stem Cell Grafts

High thoracic or cervical spinal cord injury (SCI) can lead to cardiovascular dysfunction. To monitor cardiovascular parameters, we implanted a catheter connected to a radio transmitter into the femoral artery of rats that underwent a T4 spinal cord transection with or without grafting of embryonic brainstem-derived neural stem cells expressing green fluorescent protein. Compared to other methods such as cannula insertion or tail-cuff, telemetry is advantageous to continuously monitor blood pressure and heart rate in freely moving animals. It is also capable of long term multiple data acquisitions. In spinal cord injured rats, basal cardiovascular data under unrestrained condition and autonomic dysreflexia in response to colorectal distension were successfully recorded. In addition, cardiovascular parameters before and after SCI can be compared in the same rat if a transmitter is implanted before a spinal cord transection. One limitation of the described telemetry procedure is that implantation in the femoral artery may influence the blood supply to the ipsilateral hindlimb.

We present a protocol for using a radio-telemetric system to record cardiovascular parameters in T4 spinal cord transected rats eight weeks after embryonic brainstem neural stem cell grafting into the lesion site. Telemetry is an advanced technique to accurately evaluate cardiovascular function in conscious freely moving spinal cord injured rats.

High thoracic or cervical spinal cord injury (SCI) can lead to cardiovascular dysfunction. To monitor cardiovascular parameters, we implanted a catheter ...

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 ...

Contrast Enhanced Ultrasound Imaging for Assessment of Spinal Cord Blood Flow in Experimental Spinal Cord Injury

Reduced spinal cord blood flow (SCBF) (i.e., ischemia) plays a key role in traumatic spinal cord injury (SCI) pathophysiology and is accordingly an important target for neuroprotective therapies. Although several techniques have been described to assess SCBF, they all have significant limitations. To overcome the latter, we propose the use of real-time contrast enhanced ultrasound imaging (CEU). Here we describe the application of this technique in a rat contusion model of SCI. A jugular catheter is first implanted for the repeated injection of contrast agent, a sodium chloride solution of sulphur hexafluoride encapsulated microbubbles. The spine is then stabilized with a custom-made 3D-frame and the spinal cord dura mater is exposed by a laminectomy at ThIX-ThXII. The ultrasound probe is then positioned at the posterior aspect of the dura mater (coated with ultrasound gel). To assess baseline SCBF, a single intravenous injection (400 &#181;l) of contrast agent is applied to record its passage through the intact spinal cord microvasculature. A weight-drop device is subsequently used to generate a reproducible experimental contusion model of SCI. Contrast agent is re-injected 15 min following the injury to assess post-SCI SCBF changes. CEU allows for real time and in-vivo assessment of SCBF changes following SCI. In the uninjured animal, ultrasound imaging showed uneven blood flow along the intact spinal cord. Furthermore, 15 min post-SCI, there was critical ischemia at the level of the epicenter while SCBF remained preserved in the more remote intact areas. In the regions adjacent to the epicenter (both rostral and caudal), SCBF was significantly reduced. This corresponds to the previously described &#8220;ischemic penumbra zone&#8221;. This tool is of major interest for assessing the effects of therapies aimed at limiting ischemia and the resulting tissue necrosis subsequent to SCI.

Contrast Enhanced Ultrasound imaging is a reliable in-vivo tool for quantifying spinal cord blood flow in an experimental rat spinal cord injury model. This paper contains a comprehensive protocol for application of this technique in association with a contusion model of thoracic spinal cord injury.

Reduced spinal cord blood flow (SCBF) (i.e., ischemia) plays a key role in traumatic spinal cord injury (SCI) pathophysiology and is accordingly an ...

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 ...