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Borrell JA, Krizsan-Agbas D, Nudo RJ, Frost SB. Effects of a contusive spinal cord injury on cortically-evoked spinal spiking activity in rats. J Neural Eng 2020; 17:10.1088/1741-2552/abc1b5. [PMID: 33059344 PMCID: PMC8046849 DOI: 10.1088/1741-2552/abc1b5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 10/15/2020] [Indexed: 01/23/2023]
Abstract
Objective.The purpose of this study was to determine the effects of spinal cord injury (SCI) on spike activity evoked in the hindlimb spinal cord of the rat from cortical electrical stimulation.Approach.Adult, male, Sprague Dawley rats were randomly assigned to a Healthy or SCI group. SCI rats were given a 175 kDyn dorsal midline contusion injury at the level of the T8 vertebrae. At 4 weeks post-SCI, intracortical microstimulation (ICMS) was delivered at several sites in the hindlimb motor cortex of anesthetized rats, and evoked neural activity was recorded from corresponding sites throughout the dorsoventral depths of the spinal cord and EMG activity from hindlimb muscles.Main results.In healthy rats, post-ICMS spike histograms showed reliable, evoked spike activity during a short-latency epoch 10-12 ms after the initiation of the ICMS pulse train (short). Longer latency spikes occurred between ∼20 and 60 ms, generally following a Gaussian distribution, rising above baseline at timeLON, followed by a peak response (Lp), and then falling below baseline at timeLOFF. EMG responses occurred betweenLONandLp( 25-27 ms). In SCI rats, short-latency responses were still present, long-latency responses were disrupted or eliminated, and EMG responses were never evoked. The retention of the short-latency responses indicates that spared descending spinal fibers, most likely via the cortico-reticulospinal pathway, can still depolarize spinal cord neurons after a dorsal midline contusion injury.Significance.This study provides novel insights into the role of alternate pathways for voluntary control of hindlimb movements after SCI that disrupts the corticospinal tract in the rat.
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Affiliation(s)
- Jordan A. Borrell
- Bioengineering Program, University of Kansas, Lawrence, KS, USA
- Landon Center on Aging, University of Kansas Medical Center, Kansas City, KS, USA
| | - Dora Krizsan-Agbas
- Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Randolph J. Nudo
- Landon Center on Aging, University of Kansas Medical Center, Kansas City, KS, USA
- Department of Rehabilitation Medicine, University of Kansas Medical Center, Kansas City, KS, USA
| | - Shawn B. Frost
- Landon Center on Aging, University of Kansas Medical Center, Kansas City, KS, USA
- Department of Rehabilitation Medicine, University of Kansas Medical Center, Kansas City, KS, USA
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Min J, Kim JY, Seo CH, Jeon SR, Choi KH, Jeong JH. Changes of the Electrophysiological Study in Dogs with Acute Spinal Cord Injury. Korean J Neurotrauma 2014; 10:1-5. [PMID: 27169024 PMCID: PMC4852588 DOI: 10.13004/kjnt.2014.10.1.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 04/20/2014] [Accepted: 04/21/2014] [Indexed: 12/04/2022] Open
Abstract
Objective This study describes a method for inducing spinal cord injuries in dogs by using balloon catheters via laminectomy and the subsequent changes in the electrophysiological response. Methods Female Beagle (Orient Bio, Seongnam, Korea) dogs weighing 10 kg at the time of injury were used. Under inhalation anesthesia, a posterior midline approach laminectomy was performed. A silicone balloon catheter (size 6 Fr; Sewoon Medical, Cheonan, Korea) was then inserted into the vertebral canal at the center of T10. The balloon was inflated to the maximum volume for 1, 2, or 3 days. Open field testing was performed for evaluating motor functions of the hindlimbs. Motor evoked potentials (MEPs) induced by electrical and magnetic stimulation were recorded before and after spinal cord injury. Results Open field testing yielded locomotor scores of 0 or 1 for dogs subjected to compression for 3 days. These dogs showed no obvious improvement throughout the observation period, and the tonus of their hindlimbs was flaccid. In contrast, motor functions of dogs that had experienced compression for 1 or 2 days were variable, and all dogs showed spastic tonus in their hindlimbs. In dogs subjected to after compression for 3 days, electrically stimulated MEPs for the hindlimbs showed a significant amplitude reduction. Further, hindlimb movements were not evoked by magnetic stimulation of the cervical spine and vertex area. Conclusion Compression for 3 days with a balloon catheter is a safe, reproducible, and reliable method for evaluating electrophysiological changes in a dog model of complete spinal cord injury.
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Affiliation(s)
- Joongkee Min
- Laboratory of Stem Cell Therapy, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Ji Yun Kim
- Laboratory of Stem Cell Therapy, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Cheong Hoon Seo
- Department of Rehabilitation Medicine, Hallym University Medical Center, Seoul, Korea
| | - Sang Ryong Jeon
- Laboratory of Stem Cell Therapy, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
- Department of Neurosurgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Kyoung Hyo Choi
- Laboratory of Stem Cell Therapy, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
- Department of Rehabilitation Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Je Hoon Jeong
- Laboratory of Stem Cell Therapy, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
- Department of Neurosurgery, Soonchunhyang University Bucheon Hospital, Bucheon, Korea
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Gad P, Lavrov I, Shah P, Zhong H, Roy RR, Edgerton VR, Gerasimenko Y. Neuromodulation of motor-evoked potentials during stepping in spinal rats. J Neurophysiol 2013; 110:1311-22. [PMID: 23761695 DOI: 10.1152/jn.00169.2013] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The rat spinal cord isolated from supraspinal control via a complete low- to midthoracic spinal cord transection produces locomotor-like patterns in the hindlimbs when facilitated pharmacologically and/or by epidural electrical stimulation. To evaluate the role of epidural electrical stimulation in enabling motor control (eEmc) for locomotion and posture, we recorded potentials evoked by epidural spinal cord stimulation in selected hindlimb muscles during stepping and standing in adult spinal rats. We hypothesized that the temporal details of the phase-dependent modulation of these evoked potentials in selected hindlimb muscles while performing a motor task in the unanesthetized state would be predictive of the potential of the spinal circuitries to generate stepping. To test this hypothesis, we characterized soleus and tibialis anterior (TA) muscle responses as middle response (MR; 4-6 ms) or late responses (LRs; >7 ms) during stepping with eEmc. We then compared these responses to the stepping parameters with and without a serotoninergic agonist (quipazine) or a glycinergic blocker (strychnine). Quipazine inhibited the MRs induced by eEmc during nonweight-bearing standing but facilitated locomotion and increased the amplitude and number of LRs induced by eEmc during stepping. Strychnine facilitated stepping and reorganized the LRs pattern in the soleus. The LRs in the TA remained relatively stable at varying loads and speeds during locomotion, whereas the LRs in the soleus were strongly modulated by both of these variables. These data suggest that LRs facilitated electrically and/or pharmacologically are not time-locked to the stimulation pulse but are highly correlated to the stepping patterns of spinal rats.
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Affiliation(s)
- Parag Gad
- Biomedical Engineering IDP, University of California, Los Angeles, California
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Vahabzadeh-Hagh AM, Muller PA, Gersner R, Zangen A, Rotenberg A. Translational neuromodulation: approximating human transcranial magnetic stimulation protocols in rats. Neuromodulation 2012; 15:296-305. [PMID: 22780329 PMCID: PMC5764706 DOI: 10.1111/j.1525-1403.2012.00482.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Transcranial magnetic stimulation (TMS) is a well-established clinical protocol with numerous potential therapeutic and diagnostic applications. Yet, much work remains in the elucidation of TMS mechanisms, optimization of protocols, and in development of novel therapeutic applications. As with many technologies, the key to these issues lies in the proper experimentation and translation of TMS methods to animal models, among which rat models have proven popular. A significant increase in the number of rat TMS publications has necessitated analysis of their relevance to human work. We therefore review the essential principles for the approximation of human TMS protocols in rats as well as specific methods that addressed these issues in published studies. MATERIALS AND METHODS We performed an English language literature search combined with our own experience and data. We address issues that we see as important in the translation of human TMS methods to rat models and provide a summary of key accomplishments in these areas. RESULTS An extensive literature review illustrated the growth of rodent TMS studies in recent years. Current advances in the translation of single, paired-pulse, and repetitive stimulation paradigms to rodent models are presented. The importance of TMS in the generation of data for preclinical trials is also highlighted. CONCLUSIONS Rat TMS has several limitations when considering parallels between animal and human stimulation. However, it has proven to be a useful tool in the field of translational brain stimulation and will likely continue to aid in the design and implementation of stimulation protocols for therapeutic and diagnostic applications.
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Affiliation(s)
- Andrew M. Vahabzadeh-Hagh
- Department of Neurology, Children's Hospital, Harvard Medical School, Boston, MA 02215, USA
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Paul A. Muller
- Department of Neurology, Children's Hospital, Harvard Medical School, Boston, MA 02215, USA
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Roman Gersner
- Department of Neurobiology, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Abraham Zangen
- Department of Neurobiology, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Alexander Rotenberg
- Department of Neurology, Children's Hospital, Harvard Medical School, Boston, MA 02215, USA
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
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Abstract
The corticospinal tract (CST) is a major descending pathway contributing to the control of voluntary movement in mammals. During the last decades anatomical and electrophysiological studies have demonstrated significant reorganization in the CST after spinal cord injury (SCI) in animals and humans. In animal models of SCI, anatomical evidence showed corticospinal sprouts rostral and caudal to the lesion and their integration into intraspinal axonal circuits. Electrophysiological data suggested that indirect connections from the primary motor cortex to forelimb motoneurons, via brainstem nuclei and spinal cord interneurons, or direct connections from slow uninjured corticospinal axons, might contribute to the control of movement after a CST injury. In humans with SCI, post mortem spinal cord tissue revealed anatomical changes in the CST some of which were similar but others markedly different from those found in animal models of SCI. Human electrophysiological studies have provided ample evidence for corticospinal reorganization after SCI that may contribute to functional recovery. Together these studies have revealed a large plastic capacity of the CST after SCI. There is also a limited understanding of the relationship between anatomical and electrophysiological changes in the CST and control of movement after SCI. Increasing our knowledge of the role of CST plasticity in functional restoration after SCI may support the development of more effective repair strategies.
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Affiliation(s)
- Martin Oudega
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, 4074 BST3, 3501 Fifth Avenue, Pittsburgh, PA 15261, USA.
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Shin HI, Han TR, Paik NJ. Effect of consecutive application of paired associative stimulation on motor recovery in a rat stroke model: a preliminary study. Int J Neurosci 2008; 118:807-20. [PMID: 18465426 DOI: 10.1080/00207450601123480] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
This study investigated the changes in motor evoked potential (MEP) amplitude and motor behavior index when paired associative stimulation (PAS), a conjoint stimulation of a peripheral nerve and the motor cortex, was applied in a rat stroke model. The PAS was applied to 19 rats and sham stimulation was applied to 15 rats. One part of PAS consisted of peripheral electrical stimulation of the soleus muscle and the other part was transcranial magnetic stimulation of the motor cortex. The stimulation was repeated for 30 min with a frequency of 0.05 Hz. Five sessions of PAS were applied over 5 consecutive days. The motor behavior index was higher in the PAS group than in the sham stimulation group at 7 d after ischemic brain injury. There was no lasting difference between the PAS animals and the sham stimulation group in MEP amplitude although MEP amplitude was increased immediately after PAS. MEP amplitude can be increased by the PAS paradigm in rats as well as in humans and PAS has potential therapeutic value for motor recovery after brain injury.
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Affiliation(s)
- Hyung-Ik Shin
- Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seoul, Republic of Korea
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Abstract
The importance of the in vivo dynamic nature of the circuitries within the spinal cord that generate locomotion is becoming increasingly evident. We examined the characteristics of hindlimb EMG activity evoked in response to epidural stimulation at the S1 spinal cord segment in complete midthoracic spinal cord-transected rats at different stages of postlesion recovery. A progressive and phase-dependent modulation of monosynaptic (middle) and long-latency (late) stimulation-evoked EMG responses was observed throughout the step cycle. During the first 3 weeks after injury, the amplitude of the middle response was potentiated during the EMG bursts, whereas after 4 weeks, both the middle and late responses were phase-dependently modulated. The middle- and late-response magnitudes were closely linked to the amplitude and duration of the EMG bursts during locomotion facilitated by epidural stimulation. The optimum stimulation frequency that maintained consistent activity of the long-latency responses ranged from 40 to 60 Hz, whereas the short-latency responses were consistent from 5 to 130 Hz. These data demonstrate that both middle and late evoked potentials within a motor pool are strictly gated during in vivo bipedal stepping as a function of the general excitability of the motor pool and, thus, as a function of the phase of the step cycle. These data demonstrate that spinal cord epidural stimulation can facilitate locomotion in a time-dependent manner after lesion. The long-latency responses to epidural stimulation are correlated with the recovery of weight-bearing bipedal locomotion and may reflect activation of interneuronal central pattern-generating circuits.
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Zhang YP, Shields LBE, Zhang Y, Pei J, Xu XM, Hoskins R, Cai J, Qiu MS, Magnuson DSK, Burke DA, Shields CB. Use of magnetic stimulation to elicit motor evoked potentials, somatosensory evoked potentials, and H-reflexes in non-sedated rodents. J Neurosci Methods 2007; 165:9-17. [PMID: 17628688 DOI: 10.1016/j.jneumeth.2007.05.021] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Revised: 05/14/2007] [Accepted: 05/17/2007] [Indexed: 11/21/2022]
Abstract
Assessment of locomotor function of rodents may be supplemented using electrophysiological tests which monitor the integrity of ascending and descending tracts as well as the focal circuitry of the spinal cord in non-sedated rodents. Magnetically induced SSEPs (M-SSEPs) were elicited in rats by activating the hindpaw using magnetic stimulation (MS). M-SSEP response latencies were slightly longer than those elicited by electrical stimulation. M-SSEPs were eliminated following selective dorsal column lacerations of the spinal cord, indicating that they were transmitted via this tract. Magnetically induced motor evoked potentials (M-MEPs) were elicited in mice following transcranial MS and recorded from the gastrocnemius muscles. M-MEPs performed on myelin deficient mice demonstrated longer onset latencies and smaller amplitudes than in wild-type mice. Magnetically induced H-reflexes (MH-reflexes) which assess local circuitry in the lumbosacral area of the spinal cord were performed in rats. This response disappeared following an L3 contusion spinal cord injury, however, kainic acid (KA) injection at L3, known to selectively destroy interneurons, caused a shorter latency and an increase in the amplitude of the MH-reflex. M-SSEPs and MH-reflexes in rats and M-MEPs in mice compliment locomotor evaluation in assessing the functional integrity of the spinal cord under normal and pathological conditions in the non-sedated animal.
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Affiliation(s)
- Yi Ping Zhang
- Kentucky Spinal Cord Injury Research Center, 511 South Floyd Street, Louisville, KY 40202, USA
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Nielsen JB, Perez MA, Oudega M, Enriquez-Denton M, Aimonetti JM. Evaluation of transcranial magnetic stimulation for investigating transmission in descending motor tracts in the rat. Eur J Neurosci 2007; 25:805-14. [PMID: 17328776 DOI: 10.1111/j.1460-9568.2007.05326.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
In the rat, non-invasive transcranial magnetic stimulation (TMS) has shown promise for evaluation of transmission through the spinal cord before and after repair strategies, but it is still unclear which pathways are activated by TMS. The aim of the present study was therefore to identify these pathways and to analyse the effect of TMS on spinal neurons. In 19 rats, TMS evoked responses bilaterally in forelimb (biceps brachii; BB) and hindlimb muscles (tibialis anterior). The latency and amplitude of these motor-evoked responses (MEPs) were highly variable and depended strongly on the coil position and the stimulation intensity. The most frequently observed latencies for the BB MEPs could be divided into three groups: 3-6 ms, 8-12 ms and 14-18 ms. Lesions in the dorsal columns, which destroyed the corticospinal tract at C2 and C5, significantly depressed MEPs in the mid- and high-latency ranges, but not those in the low-latency range. Lesions in the dorsolateral funiculus, which interrupted the rubrospinal tract, had no effect on MEPs in any of the latency ranges. By contrast, bilateral lesion of the reticulospinal tract and other ventro-laterally located descending pathways abolished all responses. Intracellular recordings from 54 cervical motoneurons in five rats revealed that TMS evoked excitatory postsynaptic potentials (EPSPs) at latencies that corresponded well with those of the BB MEPs. The short-latency EPSPs had rise times of around 1 ms, suggesting that they were mediated by a monosynaptic pathway. EPSPs with longer latencies had considerably longer rise times, which indicated conduction through polysynaptic pathways. Selective electrical stimulation of the pyramidal tract in the brainstem was performed in seven rats, where intracellular recordings from 70 motoneurons revealed that the earliest EPSPs and MEPs evoked by TMS were not mediated by the corticospinal tract, but by other descending motor pathways. Together, these results showed that in the rat TMS activates several descending pathways that converge on common spinal interneurons and motoneurons. Our observations confirm that the corticospinal tract has weak (and indirect) projections to cervical spinal motoneurons.
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Affiliation(s)
- J B Nielsen
- Division of Neurophysiology, Department of Medical Physiology, the Panum Institute, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark.
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Lavrov I, Gerasimenko YP, Ichiyama RM, Courtine G, Zhong H, Roy RR, Edgerton VR. Plasticity of spinal cord reflexes after a complete transection in adult rats: relationship to stepping ability. J Neurophysiol 2006; 96:1699-710. [PMID: 16823028 DOI: 10.1152/jn.00325.2006] [Citation(s) in RCA: 138] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Changes in epidurally induced (S1) spinal cord reflexes were studied as a function of the level of restoration of stepping ability after spinal cord transection (ST). Three types of responses were observed. The early response (ER) had a latency of 2.5 to 3 ms and resulted from direct stimulation of motor fibers or motoneurons. The middle response (MR) had a latency of 5 to 7 ms and was monosynaptic. The late response (LR) had a latency of 9 to 11 ms and was polysynaptic. After a complete midthoracic ST, the LR was abolished, whereas the MR was facilitated and progressively increased. The LR reappeared about 3 wk after ST and increased during the following weeks. Restoration of stepping induced by epidural stimulation at 40 Hz coincided with changes in the LR. During the first 2 wk post-ST, rats were unable to step and electrophysiological assessment failed to show any LR. Three weeks post-ST, epidural stimulation resulted in a few steps and these coincided with reappearance of the LR. The ability of rats to step progressively improved from wk 3 to wk 6 post-ST. There was a continuously improved modulation of rhythmic EMG bursts that was correlated with restoration of the LR. These results suggest that restoration of polysynaptic spinal cord reflexes after complete ST coincides with restoration of stepping function when facilitated by epidural stimulation. Combined, these findings support the view that restoration of polysynaptic spinal cord reflexes induced epidurally may provide a measure of functional restoration of spinal cord locomotor networks after ST.
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Affiliation(s)
- Igor Lavrov
- Department of Physiological Science, University of California, Los Angeles, CA 90095-1527, USA
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Fukuda S, Nakamura T, Kishigami Y, Endo K, Azuma T, Fujikawa T, Tsutsumi S, Shimizu Y. New canine spinal cord injury model free from laminectomy. ACTA ACUST UNITED AC 2005; 14:171-80. [PMID: 15795171 DOI: 10.1016/j.brainresprot.2005.01.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2004] [Revised: 01/14/2005] [Accepted: 01/17/2005] [Indexed: 11/18/2022]
Abstract
The present report details the successful development of a model for spinal cord injury (SCI). This model is simple, reproducible, and requires no laminectomy. Development of the model was carried out using fourteen dogs. A balloon catheter was inserted into the extradural space via the intervertebral foramen of each dog, then the balloon was inflated at the L1 level by injection of saline. Six dogs underwent compression with a balloon volume of 1.5 ml, three dogs with a volume of 1.0 ml, and the remaining five dogs were used as uninjured controls. We applied the Basso, Beattie, and Bresnahan (BBB) locomotor rating scale to the dogs. Compression of the spinal cord for 10 min at 1.5 ml produced severe paraplegia (BBB remained zero or one for 6 months following surgery), while compression for the same time interval at 1.0 ml produced moderate paraplegia. Electrophysiological tests showed no hindlimb movement upon stimulation cranial to the site of injury in the 1.5-ml group. The volume of abnormal-intensity lesions in the 1.0-ml group calculated using MR imaging showed no marked changes in either high- or low-intensity lesions after 3 months, whereas in the 1.5-ml group, the low-intensity lesions alone showed a marked increase. Pathological examination of the damaged spinal cord showed the formation of cavities surrounded by scar tissue containing high levels of collagen. These findings closely resembled those of clinical cases. It was concluded that 10 min of balloon compression with a volume of 1.5 ml caused irreversible paraplegia in dogs.
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Affiliation(s)
- Seijun Fukuda
- Department of Bioartificial Organs, Institute for Frontier Medical Sciences, Kyoto University, East Building 309, 53 Kawahara-cho Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
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