The work was supported by grants from NIH/NINDS (NS054883), Craig H. Neilsen Foundation (280072), and the Veterans Administration and Canadian Spinal Research Organization. We thank the Rat Resource and Research Center, University of Missouri, Columbia, Missouri, for providing GFP rats.

All animal protocols were approved by the Institutional Animal Care and Use Committee (IACUC). NIH guidelines for laboratory animal care and safety are strictly followed. Animals with surgical procedures were adequately treated for minimizing pain and discomfort.
1. Spinal Cord Curgery and Cell Grafting
<ol>
	<li>Autoclave surgical instruments prior to all surgeries. Use Hot Bead Sterilizer (Fine Science Tools) to remove pathogens and microbial contaminants from instruments between procedures on different animals. Use sterile surgical gloves, gown, and drapes during the surgery. Employ aseptic surgical technique for each surgical procedure.</li>
	<li>Anesthetize female Fischer 344 rats with a combination (2 ml/kg) of ketamine (25 mg/ml), xylazine (1.3 mg/ml), and acepromazine (0.25 mg/ml) administered via intraperitoneal injection (i.p.).</li>
	<li>Shave the back area and clean the skin repeatedly with Betadine and ethanol.</li>
	<li>Cut the skin using a #10 blade and bluntly dissect muscles layers. Use a scalpel to isolate the vertebrae, expose the T3 vertebra, and perform a dorsal laminectomy using a fine-tipped rongeurs.</li>
	<li>Incise the dura longitudinally and transect the spinal cord at T4 level using a combination of iridectomy scissors and microaspiration to create an approximately 1 mm rostrocaudal gap between the spinal cord stumps.</li>
	<li>Wait about 1 - 2 min until the bleeding fully stops, then suture muscles with 3-0 Vycril and close the skin with wound clips.</li>
	<li>Inject Lactated Ringer&#8217;s (5 ml), buprenorphine (0.035 mg/kg), and Ampicillin (33 mg/kg) subcutaneously immediately after surgery and maintain rats in a warm incubator until awake.</li>
	<li>Inject the Ringer&#8217;s and Ampicillin solution once daily up to 10 days, and buprenorphine twice daily for 3 days or until signs of pain and distress disappear. Do not return an animal to the company of other animals until fully recovered.</li>
	<li>Manually empty the bladder twice a day for about two weeks until the establishment of reflex bladder emptying, and then empty the bladder once a day throughout the survival if necessary.</li>
	<li>Two weeks later, re-anesthetize SCI rats as described above and re-expose the spinal cord lesion site. Keep the dura closed to retain implanted cells in the lesion site.</li>
	<li>Inject 10 &#181;l of cell solution (3.5 &#215; 105 &#181;l), collected from E14 ubiquitous GFP transgenic rat embryos and embedded in fibrinogen and thrombin5,6, into the epicenter of the lesion cavity and the rostral and caudal interface of lesion with multiple injection sites, using a pulled glass micropipette with an inner diameter of 40 &#181;m, connected to a Hamilton syringe.</li>
	<li>Suture the muscle layers and close the skin with wound clips.</li>
	<li>Perform post surgery injection and bladder care as described in steps 1.6 &#8211; 1.8.</li>
	<li>One week before perfusion, inject 0.5% Fluorogold (FG, 0.4 ml in distilled water) intraperitoneally to retrogradely label sympathetic preganglionic neurons in the spinal cord7.</li>
</ol>
2. Transmitter Implantation
<ol>
	<li>Soak transmittersin 2% glutaraldehyde solution (4 ml of 50% glutaraldhyde in 96 ml distilled water) for at least 1 - 2 hr (up to 10 hr) at room temperature for sterilization.</li>
	<li>Wash transmitters thoroughly with sterile 0.9% saline 3 times and store them in saline until use (no more than 1 hr).</li>
	<li>Eight weeks after E14 cell transplantation (10 weeks post injury), reanesthetize the rats that underwent a SCI with or without cell grafting and na&#239;ve control rats.</li>
	<li>Shave the abdominal area and hindlimbs. Clean the skin with Betadine. Place the rat on the surgical table in supine position.</li>
	<li>Incise the skin on the ventral abdomen and inner thigh on the right side using a #15 blade.</li>
	<li>Cut through the subcutaneous connective tissues to expose the bundle of femoral vessels and nerve using a small scissors.</li>
	<li>Separate the femoral artery from the vein and the nerve using a fine forceps with curved tips.</li>
	<li>Put three silk sutures underneath the artery and make a loose knot in each suture.</li>
	<li>Apply 0.1 ml Lidocaine (2%) to the surface of the artery to elicit vasodilation for subsequent catheterization.</li>
	<li>Secure the vessel distally with a permanent silk knot and temporary block proximally by stretching a loose silk suture.</li>
	<li>Puncture the artery using a 20 gauge curved needle and insert the tip of the telemeter catheter (8 cm long) using a catheter insertion tool.</li>
	<li>Insert the catheter rostrally up to 4 cm thereby placing the tip in the thoracic aorta.</li>
	<li>Anchor the catheter within the vessel by tying three silk sutures around the femoral artery.</li>
	<li>Make a subcutaneous pocket along the flank between the caudal edge of ribcage and the most cranial extension of knee&#39;s range with a blunt scissors.</li>
	<li>Insert the transmitter body into the pocket and suture to the connective tissue surrounding the transmitter to avoid excessive movement.</li>
	<li>Suture the skin with No. 6 silk thread.</li>
	<li>Inject Lactated Ringer&#8217;s (5 ml), buprenorphine (0.035 mg/kg), and Ampicillin (33 mg/kg) subcutaneously immediately after surgery and maintain rats in a warm incubator until awake.</li>
</ol>
3. Basal Mean Arterial Pressure (MAP) and Heart Rate (HR) Recording
<ol>
	<li>As early as one day following transmitter implantation, put a single animal on the receiver pad and turn the transmitter on. Wait for around 10 - 15 min to habituate the animal and stabilize the cardiovascular parameters.</li>
	<li>Record resting MAP and HR, which are derived from the pulse arterial pressure with a computerized data acquisition system for at least 1 hr. Collect data every 5 sec.</li>
	<li>Monitor the animals continuously and remove data points during the occurrence of visible spasms. For each animal, average data points to obtain mean values.</li>
</ol>
4. Colorectal Distension-induced Autonomic Dysreflexia
<ol>
	<li>Restrain NSC-grafted or SCI control rats in a towel supplied with food pellets inside on the transmitter receiver. Usually rats can stay cooperatively during the procedure.</li>
	<li>Insert a latex balloon-tipped catheter into the rectum for approximately 2 cm and secure it to the tail with tape8.</li>
	<li>Turn the transmitter on and wait for 10 - 15 min allowing the blood pressure to return to preinsertion baseline.</li>
	<li>Induce colorectal distension by inflation of the balloon slowly over 10 sec with 1.4 ml of air for 1 min, to generate a pressure of approximately 30 mmHg.</li>
	<li>Record MAP and HR 1 min before, 1 min during, and 1 min after colorectal distension; sample data every 3 sec during the 3 min procedure.</li>
	<li>Perform 2 - 3 trials per animal with at least 15 min recovery interval between two trials.</li>
	<li>Overdose animals (i. p.) with double dose anesthesia combination described above if no further evaluation.&#160;Perfuse animals with saline followed by 4% paraformaldehyde.</li>
	<li>For each animal, average the values before and during colorectal distension respectively; calculate the difference between baseline and distension-induced MAP and HR changes for each trial; average over the 2 - 3 trials to obtain mean values.</li>
</ol>
5. Transmitter Cleaning
<ol>
	<li>Remove the transmitter from the animal body after anesthesia but before perfusion. Soak immediately in a beaker filled with distilled water until cleaning; avoid drying of the telemeter device.</li>
	<li>Transfer the telemeter to 1% Terg-A-Zyme enzymatic cleaning solution (10 g/L water) for 24 hr at room temperature.</li>
	<li>Regel the tip of transmitter catheter with a blunt 30 gauge needle connected to the regel syringe.</li>
	<li>Carefully dry the transmitter using a folded soft tissue and store it in the original plastic tray.</li>
</ol>

<ol>
	<li>Krassioukov, A. V., Furlan, J. C., 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=Autonomic+dysreflexia+in+acute+spinal+cord+injury:+an+under-recognized+clinical+entity.">Autonomic dysreflexia in acute spinal cord injury: an under-recognized clinical entity.</a> J Neurotrauma. 20, 707-716 (2003).</li><li>Lindan, R., Joiner, E., Freehafer, A. A., Hazel, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Incidence+and+clinical+features+of+autonomic+dysreflexia+in+patients+with+spinal+cord+injury.">Incidence and clinical features of autonomic dysreflexia in patients with spinal cord injury.</a> Paraplegia. 18, 285-292 (1980).</li><li>Inskip, J. A., Ramer, L. M., Ramer, M. S., Krassioukov, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Autonomic+assessment+of+animals+with+spinal+cord+injury:+tools,+techniques+and+translation.">Autonomic assessment of animals with spinal cord injury: tools, techniques and translation.</a> Spinal Cord. 47, 2-35 (2009).</li><li>Mayorov, D. N., Adams, M. A., Krassioukov, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Telemetric+blood+pressure+monitoring+in+conscious+rats+before+and+after+compression+injury+of+spinal+cord.">Telemetric blood pressure monitoring in conscious rats before and after compression injury of spinal cord.</a> J Neurotrauma. 18, 727-736 (2001).</li><li>Hou, S., Tom, V. J., Graham, L., Lu, P., Blesch, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Partial+restoration+of+cardiovascular+function+by+embryonic+neural+stem+cell+grafts+after+complete+spinal+cord+transection.">Partial restoration of cardiovascular function by embryonic neural stem cell grafts after complete spinal cord transection.</a> J Neurosci. 33, 17138-17149 (2013).</li><li>Lu, P., 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=Long-distance+growth+and+connectivity+of+neural+stem+cells+after+severe+spinal+cord+injury.">Long-distance growth and connectivity of neural stem cells after severe spinal cord injury.</a> Cell. 150, 1264-1273 (2012).</li><li>Akhavan, M., Hoang, T. X., Havton, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+detection+of+fluorogold-labeled+neurons+in+long-term+studies.">Improved detection of fluorogold-labeled neurons in long-term studies.</a> J Neurosci Methods. 152, 156-162 (2006).</li><li>Maiorov, D. N., Fehlings, M. G., Krassioukov, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Relationship+between+severity+of+spinal+cord+injury+and+abnormalities+in+neurogenic+cardiovascular+control+in+conscious+rats.">Relationship between severity of spinal cord injury and abnormalities in neurogenic cardiovascular control in conscious rats.</a> J Neurotrauma. 15, 365-374 (1998).</li><li>Laird, A. S., Carrive, P., Waite, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiovascular+and+temperature+changes+in+spinal+cord+injured+rats+at+rest+and+during+autonomic+dysreflexia.">Cardiovascular and temperature changes in spinal cord injured rats at rest and during autonomic dysreflexia.</a> J Physiol. 577, 539-548 (2006).</li><li>Phillips, A. A., Krassioukov, A. V., Ainslie, P. N., Warburton, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Baroreflex+function+after+spinal+cord+injury.">Baroreflex function after spinal cord injury.</a> J Neurotrauma. 29, 2431-2445 (2012).</li><li>Osborn, J. W., Taylor, R. F., Schramm, L. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determinants+of+arterial+pressure+after+chronic+spinal+transection+in+rats.">Determinants of arterial pressure after chronic spinal transection in rats.</a> Am J Physiol. 256, 666-673 (1989).</li><li>Rabchevsky, A. G., 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=Effects+of+gabapentin+on+muscle+spasticity+and+both+induced+as+well+as+spontaneous+autonomic+dysreflexia+after+complete+spinal+cord+injury.">Effects of gabapentin on muscle spasticity and both induced as well as spontaneous autonomic dysreflexia after complete spinal cord injury.</a> Front Physiol. 3, 329 (2012).</li><li>Hou, S., Lu, P., Blesch, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+supraspinal+vasomotor+pathways+and+autonomic+dysreflexia+after+spinal+cord+injury+in+F344+rats.">Characterization of supraspinal vasomotor pathways and autonomic dysreflexia after spinal cord injury in F344 rats.</a> Auton Neurosci. 176, 54-63 (2013).</li></ol>

The authors have nothing to disclose.

Traditionally, a fluid filled cannula is inserted into the artery and connected to a pressure transducer to record cardiovascular parameters as a terminal snapshot in each animal11. To continuously monitor cardiovascular performance for a long time, radio-telemetric systems are employed in many laboratories. This more refined tool can record blood pressure in conscious, freely moving animals. Compared to fluid filled catheters, telemetry is considered a more advanced technique to accurately evaluate cardiovasc...

Cardiovascular dysfunction occurs after spinal cord injury (SCI) at high levels. It is manifested in disordered blood pressure and heart rate at rest, orthostatic hypotension, exercise-induced hypotension, and autonomic dysreflexia characterized by episodes of hypertension and baroreflex-mediated bradycardia in response to sensory stimuli below the injury level1,2. These symptoms interfere with the daily living of spinal cord injured patients. Thus, it is important to establish effective tools for the investigation of cardiovascular changes in animals with SCI and experimental treatments.
To investigate cardiovascular function in animals, several techniques have been used to monitor blood pressure and heart rate. Central cardiovascular parameters can be recorded by cannula insertion and telemetry, whereas noninvasive tail-cuffs can be employed to measure peripheral blood pressure3. Compared to other methods, telemetry has the main advantage that it allows for continuous recording in freely moving animals and long-term monitoring of cardiovascular function4. In SCI animal models, the changes in peripheral blood pressure after experimental stimulation may not be large enough to be detected. Accordingly, suitable cardiac monitoring technique should be selected for animals with SCI.
In the present study, a radio-telemetric system was introduced to monitor cardiovascular function in adult rats after complete spinal cord transection. Rats received grafts of syngeneic rat embryonic day 14 (E14) brainstem-derived neural stem cells (BS-NSCs) in the lesion site. Rats with injury and no transplant and na&#239;ve, uninjured rats served as controls. The procedure of telemetry includes transmitter sterilization and implantation (Figure 1), recording of basal cardiovascular parameter, colorectal distension-induced responses, and transmitter cleaning and storage.

<table border="0" cellpadding="0" cellspacing="0" width="580">
	<tbody>
		<tr height="21">
			<td colspan="2" height="21" style="height:21px;width:315px;">Table of Specific Materials/Equipment:</td>
			<td style="width:103px;"></td>
			<td style="width:164px;"></td>
		</tr>
		<tr height="20">
			<td height="41" rowspan="2" style="height:41px;width:120px;">Reagents</td>
			<td rowspan="2" style="width:195px;">Company</td>
			<td rowspan="2" style="width:103px;">Catalogue</td>
			<td rowspan="2" style="width:164px;">Comment</td>
		</tr>
		<tr height="21">
		</tr>
		<tr height="62">
			<td height="83" rowspan="2" style="height:83px;width:120px;">Fibrinogen (rat)</td>
			<td rowspan="2" style="width:195px;">Sigma</td>
			<td rowspan="2" style="width:103px;">F6755-25MG</td>
			<td rowspan="2" style="width:164px;">2 hr at 37oC to dissovle</td>
		</tr>
		<tr height="21">
		</tr>
		<tr height="59">
			<td height="80" rowspan="2" style="height:80px;width:120px;">Thrombin (rat)</td>
			<td rowspan="2" style="width:195px;">Sigma</td>
			<td rowspan="2" style="width:103px;">T5772-100UN</td>
			<td rowspan="2" style="width:164px;">Dissovle in 10 mM CaCl2</td>
		</tr>
		<tr height="21">
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:120px;">1% Terg-A-Zyme</td>
			<td style="width:195px;">Sigma</td>
			<td style="width:103px;">Z273287</td>
			<td style="width:164px;">Enzymatic solution for telemeter cleaning</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:120px;">Fluorogold</td>
			<td style="width:195px;">Fluorochrome</td>
			<td style="width:103px;"></td>
			<td style="width:164px;">Dissovle in distilled water and avoid light</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:120px;">Telemeter&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; (PA-C40)</td>
			<td style="width:195px;">Data Sciences International</td>
			<td style="width:103px;"></td>
			<td style="width:164px;"></td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:120px;">Telementric recording and analysis system</td>
			<td style="width:195px;">Data Sciences International</td>
			<td style="width:103px;"></td>
			<td style="width:164px;">Signal stimulator, Data Exchange Matrix, receivers, Ambient pressure reference monitor</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:120px;">Balloon-tipped catheter</td>
			<td style="width:195px;">Edward Lifesciences</td>
			<td style="width:103px;">111F7-P</td>
			<td style="width:164px;">For colorectal distension</td>
		</tr>
	</tbody>
</table>

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.

Using the above described telemetry technique, we successfully recorded cardiovascular parameters in spinal cord injured animals. In animals with SCI alone, MAP was significantly reduced whereas HR increased compared to na&#239;ve animals, consistent with previous reports9. In animals with BS-NSC grafting, MAP and HR approached levels measured in na&#239;ve animals (Figure 2). During colorectal distension, a rat was regarded as dysreflexic if the noxious stimulation produced a rise in MAP and ...

Watch this Scientific Journal Video about A Radio-telemetric System to Monitor Cardiovascular Function in Rats with Spinal Cord Transection and Embryonic Neural Stem Cell Grafts at JoVE.com

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

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 ...

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10.4K Views.  Drexel University College of Medicine. 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.

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

Assessing Endothelial Vasodilator Function with the Endo-PAT 2000

The endothelium is a delicate monolayer of cells that lines all blood vessels, and which comprises the systemic and lymphatic capillaries. By virtue of the panoply of paracrine factors that it secretes, the endothelium regulates the contractile and proliferative state of the underlying vascular smooth muscle, as well as the interaction of the vessel wall with circulating blood elements. Because of its central role in mediating vessel tone and growth, its position as gateway to circulating immune cells, and its local regulation of hemostasis and coagulation, the the properly functioning endothelium is the key to cardiovascular health. Conversely, the earliest disorder in most vascular diseases is endothelial dysfunction.
In the arterial circulation, the healthy endothelium generally exerts a vasodilator influence on the vascular smooth muscle. There are a number of methods to assess endothelial vasodilator function. The Endo-PAT 2000 is a new device that is used to assess endothelial vasodilator function in a rapid and non-invasive fashion. Unlike the commonly used technique of duplex ultra-sonography to assess flow-mediated vasodilation, it is totally non-operator-dependent, and the equipment is an order of magnitude less expensive. The device records endothelium-mediated changes in the digital pulse waveform known as the PAT ( peripheral Arterial Tone) signal, measured with a pair of novel modified plethysmographic probes situated on the finger index of each hand. Endothelium-mediated changes in the PAT signal are elicited by creating a downstream hyperemic response. Hyperemia is induced by occluding blood flow through the brachial artery for 5 minutes using an inflatable cuff on one hand. The response to reactive hyperemia is calculated automatically by the system. A PAT ratio is created using the post and pre occlusion values. These values are normalized to measurements from the contra-lateral arm, which serves as control for non-endothelial dependent systemic effects. Most notably, this normalization controls for fluctuations in sympathetic nerve outflow that may induce changes in peripheral arterial tone that are superimposed on the hyperemic response.
In this video we demonstrate how to use the Endo-PAT 2000 to perform a clinically relevant assessment of endothelial vasodilator function.

A noninvasive procedure to assess endothelial function is demonstrated using the Endo-PAT 2000.

The endothelium is a delicate monolayer of cells that lines all blood vessels, and which comprises the systemic and lymphatic capillaries. By virtue of ...

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 ...

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 ...

Synergetic Use of Neural Precursor Cells and Self-assembling Peptides in Experimental Cervical Spinal Cord Injury

Spinal cord injuries (SCI) cause serious neurological impairment and psychological, economic, and social consequences for patients and their families. Clinically, more than 50% of SCI affect the cervical spine1. As a consequence of the primary injury, a cascade of secondary mechanisms including inflammation, apoptosis, and demyelination occur finally leading to tissue scarring and development of intramedullary cavities2,3. Both represent physical and chemical barriers to cell transplantation, integration, and regeneration. Therefore, shaping the inhibitory environment and bridging cavities to create a supportive milieu for cell transplantation and regeneration is a promising therapeutic target4. Here, a contusion/compression model of cervical SCI using an aneurysm clip is described. This model is more clinically relevant than other experimental models, since complete transection or ruptures of the cord are rare. Also in comparison to the weight drop model, which in particular damage the dorsum columns, circumferential compression of the spinal cord appears advantageous. Clip closing force and duration can be adjusted to achieve different injury severity. A ring spring facilitates precise calibration and constancy of clip force. Under physiological conditions, synthetic self-assembling peptides (SAP) self-assemble into nanofibers and thus, are appealing for application in SCI5. They can be injected directly into the lesion minimizing damage to the cord. SAPs are biocompatible structures erecting scaffolds to bridge intramedullary cavities and thus, equip the damaged cord for regenerative treatments. K2(QL)6K2 (QL6) is a novel SAP introduced by Dong et al.6 In comparison to other peptides, QL6 self-assembles into &#946;-sheets at neutral pH6.14 days after SCI, after the acute stage, SAPs are injected into the center of the lesion and neural precursor cells (NPC) are injected into adjacent dorsal columns. In order to support cell survival, transplantation is combined with continuous subdural administration of growth factors by osmotic micro pumps for 7 days.

Treating cervical spinal cord injury with both self-assembling peptides (SAP) and neural precursor cells (NPC), together with growth factors, is a promising approach to promote regeneration and recovery. A contusion/compression aneurysm clip rat model of cervical SCI and combined treatment involving SAP injection and NPC transplantation is established.

Spinal cord injuries (SCI) cause serious neurological impairment and psychological, economic, and social consequences for patients and their families. ...

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 ...

Photothrombosis-induced Focal Ischemia as a Model of Spinal Cord Injury in Mice

Spinal cord injury (SCI) is a devastating clinical condition causing permanent changes in sensorimotor and autonomic functions of the spinal cord (SC) below the site of injury. The secondary ischemia that develops following the initial mechanical insult is a serious complication of the SCI and severely impairs the function and viability of surviving neuronal and non-neuronal cells in the SC. In addition, ischemia is also responsible for the growth of lesion during chronic phase of injury and interferes with the cellular repair and healing processes. Thus there is a need to develop a spinal cord ischemia model for studying the mechanisms of ischemia-induced pathology. Focal ischemia induced by photothrombosis (PT) is a minimally invasive and very well established procedure used to investigate the pathology of ischemia-induced cell death in the brain. Here, we describe the use of PT to induce an ischemic lesion in the spinal cord of mice. Following retro-orbital sinus injection of Rose Bengal, the posterior spinal vein and other capillaries on the dorsal surface of SC were irradiated with a green light resulting in the formation of a thrombus and thus ischemia in the affected region. Results from histology and immunochemistry studies show that PT-induced ischemia caused spinal cord infarction, loss of neurons and reactive gliosis. Using this technique a highly reproducible and relatively easy model of SCI in mice can be achieved that would serve the purpose of scientific investigations into the mechanisms of ischemia induced cell death as well as the efficacy of neuroprotective drugs. This model will also allow exploration of the pathological changes that occur following SCI in live mice like axonal degeneration and regeneration, neuronal and astrocytic Ca2+ signaling using two-photon microscopy.

Photothrombosis is a minimally invasive and highly reproducible procedure to induce focal ischemia in the spinal cord and serves as a model of spinal cord injury in mice.

Spinal cord injury (SCI) is a devastating clinical condition causing permanent changes in sensorimotor and autonomic functions of the spinal cord (SC) ...

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 ...

Vein Interposition Model: A Suitable Model to Study Bypass Graft Patency

Bypass grafting is an established treatment method for coronary artery disease. Graft patency continues to be the Achilles heel of saphenous vein grafts. Research models for bypass graft failure are essential for a better understanding of pathobiological and pathophysiological processes during graft patency loss. Large animal models, such as pigs or sheep, resemble human anatomical structures but require special facilities and equipment. This video describes a rat vein interposition model to investigate vein graft patency loss. Rats are inexpensive and easy to handle. Compared to mouse models, the convenient size of rats permits better operability and enables a sufficient amount of material to be obtained for further diverse analysis. In brief, the inferior epigastric vein of a donor rat is harvested and used to replace a segment of the femoral artery. Anastomosis is conducted via single stitches and sealed with fibrin glue. Graft patency can be monitored non-invasively using duplex sonography. Myointimal hyperplasia, which is the main cause for graft patency loss, develops progressively over time and can be calculated from histological cross sections.

This video demonstrates a model to study the development of myointimal hyperplasia after venous interposition surgery in rats.

Bypass grafting is an established treatment method for coronary artery disease. Graft patency continues to be the Achilles heel of saphenous vein grafts. ...

Studying the Hypothalamic Insulin Signal to Peripheral Glucose Intolerance with a Continuous Drug Infusion System into the Mouse Brain

Insulin regulates systematic metabolism in the hypothalamus and the peripheral insulin response. An inflammatory reaction in peripheral adipose tissues contributes to type 2 diabetes mellitus (T2DM) development and appetite regulation in the hypothalamus. Chemokine CCL5 and C-C chemokine receptor type 5 (CCR5) levels have been suggested to mediate arteriosclerosis and glucose intolerance in type 2 diabetes mellitus (T2DM). In addition, CCL5 plays a neuroendocrine role in the hypothalamus by regulating food intake and body temperature, thus, prompting us to investigate its function in hypothalamic insulin signaling and the regulation of peripheral glucose metabolism.
The micro-osmotic pump brain infusion system is a quick and precise way to manipulate CCL5 function and study its effect in the brain. It also provides a convenient alternative approach to generating a transgenic knockout animal. In this system, CCL5 signaling was blocked by intracerebroventricular (ICV) infusion of its antagonist, MetCCL5, using a micro-osmotic pump. The peripheral glucose metabolism and insulin responsiveness was detected by the Oral Glucose Tolerance Test (OGTT) and Insulin Tolerance Test (ITT). Insulin signaling activity was then analyzed by protein blot from tissue samples derived from the animals.
After 7-14 days of MetCCL5 infusion, the glucose metabolism and insulin responsiveness was impaired in mice, as seen in the results of the OGTT and ITT. The IRS-1 serine302 phosphorylation was increased and the Akt activity was reduced in mice hypothalamic neurons following CCL5 inhibition. Altogether, our data suggest that blocking CCL5 in the mouse brain increases the phosphorylation of IRS-1 S302 and interrupts hypothalamic insulin signaling, leading to a decrease in insulin function in peripheral tissues as well as the impairment of glucose metabolism.

This protocol studies the role of chemokine (C-C motif) ligand 5 (CCL5) in the hypothalamus by delivering an antagonist, MetCCL5, into the mouse brain using a micro-osmotic pump brain infusion system. This transient inhibition of CCL5 activity interrupted hypothalamic insulin signaling, leading to glucose intolerance and peripheral systemic insulin sensitivity.

Insulin regulates systematic metabolism in the hypothalamus and the peripheral insulin response. An inflammatory reaction in peripheral adipose tissues ...

Balloon-based Injury to Induce Myointimal Hyperplasia in the Mouse Abdominal Aorta

The use of animal models is essential for a better understanding of MH, one major cause for arterial stenosis.In this article, we demonstrate a murine balloon denudation model, which is comparable with established vessel injury models in large animals. The aorta denudation model with balloon catheters mimics the clinical setting and leads to comparable pathobiological and physiological changes. Briefly, after performing a horizontal incision in the aorta abdominalis, a balloon catheter will be inserted into the vessel, inflated, and introduced retrogradely. Inflation of the balloon will lead to intima injury and overdistension of the vessel. After removing the catheter, the aortic incision will be closed with single stiches. The model shown in this article is reproducible, easy to perform, and can be established quickly and reliably. It is especially suitable for evaluating expensive experimental therapeutic agents, which can be applied in an economical fashion. By using different knockout-mouse strains, the impact of different genes on MH development can be assessed.

This article demonstrates a murine model to study the development of myointimal hyperplasia (MH) after aortic balloon injury.

The use of animal models is essential for a better understanding of MH, one major cause for arterial stenosis.In this article, we demonstrate a murine ...