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Saraswat Ohri S, Forston MD, Myers SA, Brown BL, Andres KR, Howard RM, Gao Y, Liu Y, Cavener DR, Hetman M, Whittemore SR. Oligodendrocyte-selective deletion of the eIF2α kinase Perk/Eif2ak3 limits functional recovery after spinal cord injury. Glia 2024; 72:1259-1272. [PMID: 38587137 DOI: 10.1002/glia.24525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/13/2024] [Accepted: 03/04/2024] [Indexed: 04/09/2024]
Abstract
After spinal cord injury (SCI), re-establishing cellular homeostasis is critical to optimize functional recovery. Central to that response is PERK signaling, which ultimately initiates a pro-apoptotic response if cellular homeostasis cannot be restored. Oligodendrocyte (OL) loss and white matter damage drive functional consequences and determine recovery potential after thoracic contusive SCI. We examined acute (<48 h post-SCI) and chronic (6 weeks post-SCI) effects of conditionally deleting Perk from OLs prior to SCI. While Perk transcript is expressed in many types of cells in the adult spinal cord, its levels are disproportionately high in OL lineage cells. Deletion of OL-Perk prior to SCI resulted in: (1) enhanced acute phosphorylation of eIF2α, a major PERK substrate and the critical mediator of the integrated stress response (ISR), (2) enhanced acute expression of the downstream ISR genes Atf4, Ddit3/Chop, and Tnfrsf10b/Dr5, (3) reduced acute OL lineage-specific Olig2 mRNA, but not neuronal or astrocytic mRNAs, (4) chronically decreased OL content in the spared white matter at the injury epicenter, (5) impaired hindlimb locomotor recovery, and (6) reduced chronic epicenter white matter sparing. Cultured primary OL precursor cells with reduced PERK expression and activated ER stress response showed: (1) unaffected phosphorylation of eIF2α, (2) enhanced ISR gene induction, and (3) increased cytotoxicity. Therefore, OL-Perk deficiency exacerbates ISR signaling and potentiates white matter damage after SCI. The latter effect is likely mediated by increased loss of Perk-/- OLs.
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Affiliation(s)
- Sujata Saraswat Ohri
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Interdisciplinary Program in Translational Neuroscience, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Michael D Forston
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
- Department of Anatomical Sciences & Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Scott A Myers
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
| | - Brandon L Brown
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
- Department of Interdisciplinary Program in Translational Neuroscience, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Anatomical Sciences & Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Kariena R Andres
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
| | - Russell M Howard
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
| | - Yonglin Gao
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
| | - Yu Liu
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
| | - Douglas R Cavener
- Department of Biology, Penn State University, University Park, Pennsylvania, USA
| | - Michal Hetman
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Interdisciplinary Program in Translational Neuroscience, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Anatomical Sciences & Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, Kentucky, USA
- M.D./Ph.D. Program, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Scott R Whittemore
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Interdisciplinary Program in Translational Neuroscience, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Anatomical Sciences & Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, Kentucky, USA
- M.D./Ph.D. Program, University of Louisville School of Medicine, Louisville, Kentucky, USA
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Metcalfe M, David BT, Langley BC, Hill CE. Elevation of NAD + by nicotinamide riboside spares spinal cord tissue from injury and promotes locomotor recovery. Exp Neurol 2023; 368:114479. [PMID: 37454712 DOI: 10.1016/j.expneurol.2023.114479] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 06/28/2023] [Accepted: 07/12/2023] [Indexed: 07/18/2023]
Abstract
Spinal cord injury (SCI)-induced tissue damage spreads to neighboring spared cells in the hours, days, and weeks following injury, leading to exacerbation of tissue damage and functional deficits. Among the biochemical changes is the rapid reduction of cellular nicotinamide adenine dinucleotide (NAD+), an essential coenzyme for energy metabolism and an essential cofactor for non-redox NAD+-dependent enzymes with critical functions in sensing and repairing damaged tissue. NAD+ depletion propagates tissue damage. Augmenting NAD+ by exogenous application of NAD+, its synthesizing enzymes, or its cellular precursors mitigates tissue damage. Nicotinamide riboside (NR) is considered to be one of the most promising NAD+ precursors for clinical application due to its ability to safely and effectively boost cellular NAD+ synthesis in rats and humans. Moreover, various preclinical studies have demonstrated that NR can provide tissue protection. Despite these promising findings, little is known about the potential benefits of NR in the context of SCI. In the current study, we tested whether NR administration could effectively increase NAD+ levels in the injured spinal cord and whether this augmentation of NAD+ would promote spinal cord tissue protection and ultimately lead to improvements in locomotor function. Our findings indicate that administering NR (500 mg/kg) intraperitoneally from four days before to two weeks after a mid-thoracic contusion-SCI injury, effectively doubles NAD+ levels in the spinal cord of Long-Evans rats. Moreover, NR administration plays a protective role in preserving spinal cord tissue post-injury, particularly in neurons and axons, as evident from the observed gray and white matter sparing. Additionally, it enhances motor function, as evaluated through the BBB subscore and missteps on the horizontal ladderwalk. Collectively, these findings demonstrate that administering NR, a precursor of NAD+, increases NAD+ within the injured spinal cord and effectively mitigates the tissue damage and functional decline that occurs following SCI.
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Affiliation(s)
- Mariajose Metcalfe
- Burke Neurological Institute, White Plains, NY, United States; Weill Cornell Medicine, Feil Family Brain and Mind Research Institute, New York, NY, United States.
| | - Brian T David
- Burke Neurological Institute, White Plains, NY, United States; Weill Cornell Medicine, Feil Family Brain and Mind Research Institute, New York, NY, United States.
| | - Brett C Langley
- Burke Neurological Institute, White Plains, NY, United States; Weill Cornell Medicine, Feil Family Brain and Mind Research Institute, New York, NY, United States.
| | - Caitlin E Hill
- Burke Neurological Institute, White Plains, NY, United States; Weill Cornell Medicine, Feil Family Brain and Mind Research Institute, New York, NY, United States.
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Nogo-A and LINGO-1: Two Important Targets for Remyelination and Regeneration. Int J Mol Sci 2023; 24:ijms24054479. [PMID: 36901909 PMCID: PMC10003089 DOI: 10.3390/ijms24054479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/13/2023] [Accepted: 02/22/2023] [Indexed: 02/26/2023] Open
Abstract
Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) that causes progressive neurological disability in most patients due to neurodegeneration. Activated immune cells infiltrate the CNS, triggering an inflammatory cascade that leads to demyelination and axonal injury. Non-inflammatory mechanisms are also involved in axonal degeneration, although they are not fully elucidated yet. Current therapies focus on immunosuppression; however, no therapies to promote regeneration, myelin repair, or maintenance are currently available. Two different negative regulators of myelination have been proposed as promising targets to induce remyelination and regeneration, namely the Nogo-A and LINGO-1 proteins. Although Nogo-A was first discovered as a potent neurite outgrowth inhibitor in the CNS, it has emerged as a multifunctional protein. It is involved in numerous developmental processes and is necessary for shaping and later maintaining CNS structure and functionality. However, the growth-restricting properties of Nogo-A have negative effects on CNS injury or disease. LINGO-1 is also an inhibitor of neurite outgrowth, axonal regeneration, oligodendrocyte differentiation, and myelin production. Inhibiting the actions of Nogo-A or LINGO-1 promotes remyelination both in vitro and in vivo, while Nogo-A or LINGO-1 antagonists have been suggested as promising therapeutic approaches for demyelinating diseases. In this review, we focus on these two negative regulators of myelination while also providing an overview of the available data on the effects of Nogo-A and LINGO-1 inhibition on oligodendrocyte differentiation and remyelination.
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Wang Z, Romanski A, Mehra V, Wang Y, Brannigan M, Campbell BC, Petsko GA, Tsoulfas P, Blackmore MG. Brain-wide analysis of the supraspinal connectome reveals anatomical correlates to functional recovery after spinal injury. eLife 2022; 11:76254. [PMID: 35838234 PMCID: PMC9345604 DOI: 10.7554/elife.76254] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 07/12/2022] [Indexed: 11/15/2022] Open
Abstract
The supraspinal connectome is essential for normal behavior and homeostasis and consists of numerous sensory, motor, and autonomic projections from brain to spinal cord. Study of supraspinal control and its restoration after damage has focused mostly on a handful of major populations that carry motor commands, with only limited consideration of dozens more that provide autonomic or crucial motor modulation. Here, we assemble an experimental workflow to rapidly profile the entire supraspinal mesoconnectome in adult mice and disseminate the output in a web-based resource. Optimized viral labeling, 3D imaging, and registration to a mouse digital neuroanatomical atlas assigned tens of thousands of supraspinal neurons to 69 identified regions. We demonstrate the ability of this approach to clarify essential points of topographic mapping between spinal levels, measure population-specific sensitivity to spinal injury, and test the relationships between region-specific neuronal sparing and variability in functional recovery. This work will spur progress by broadening understanding of essential but understudied supraspinal populations.
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Affiliation(s)
- Zimei Wang
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - Adam Romanski
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - Vatsal Mehra
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - Yunfang Wang
- Department of Neurological Surgery, University of Miami, Miami, United States
| | - Matthew Brannigan
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - Benjamin C Campbell
- Helen and Robert Appel Alzheimer's Disease Research Institute, Cornell University, New York, United States
| | - Gregory A Petsko
- Helen and Robert Appel Alzheimer's Disease Research Institute, Cornell University, New York, United States
| | - Pantelis Tsoulfas
- Department of Neurological Surgery, University of Miami, Miami, United States
| | - Murray G Blackmore
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
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Le Ray D, Guayasamin M. How Does the Central Nervous System for Posture and Locomotion Cope With Damage-Induced Neural Asymmetry? Front Syst Neurosci 2022; 16:828532. [PMID: 35308565 PMCID: PMC8927091 DOI: 10.3389/fnsys.2022.828532] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 02/07/2022] [Indexed: 12/28/2022] Open
Abstract
In most vertebrates, posture and locomotion are achieved by a biomechanical apparatus whose effectors are symmetrically positioned around the main body axis. Logically, motor commands to these effectors are intrinsically adapted to such anatomical symmetry, and the underlying sensory-motor neural networks are correspondingly arranged during central nervous system (CNS) development. However, many developmental and/or life accidents may alter such neural organization and acutely generate asymmetries in motor operation that are often at least partially compensated for over time. First, we briefly present the basic sensory-motor organization of posturo-locomotor networks in vertebrates. Next, we review some aspects of neural plasticity that is implemented in response to unilateral central injury or asymmetrical sensory deprivation in order to substantially restore symmetry in the control of posturo-locomotor functions. Data are finally discussed in the context of CNS structure-function relationship.
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Blackmore M, Batsel E, Tsoulfas P. Widening spinal injury research to consider all supraspinal cell types: Why we must and how we can. Exp Neurol 2021; 346:113862. [PMID: 34520726 PMCID: PMC8805209 DOI: 10.1016/j.expneurol.2021.113862] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/19/2021] [Accepted: 09/08/2021] [Indexed: 01/05/2023]
Abstract
The supraspinal connectome consists of dozens of neuronal populations that project axons from the brain to the spinal cord to influence a wide range of motor, autonomic, and sensory functions. The complexity and wide distribution of supraspinal neurons present significant technical challenges, leading most spinal cord injury research to focus on a handful of major pathways such as the corticospinal, rubrospinal, and raphespinal. Much less is known about many additional populations that carry information to modulate or compensate for these main pathways, or which carry pre-autonomic and other information of high value to individuals with spinal injury. A confluence of technical developments, however, now enables a whole-connectome study of spinal cord injury. Improved viral labeling, tissue clearing, and automated registration to 3D atlases can quantify supraspinal neurons throughout the murine brain, offering a practical means to track responses to injury and treatment on an unprecedented scale. Here we discuss the need for expanded connectome-wide analyses in spinal injury research, illustrate the potential by discussing a new web-based resource for brain-wide study of supraspinal neurons, and highlight future prospects for connectome analyses.
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Affiliation(s)
- Murray Blackmore
- Department of Biomedical Sciences, Marquette University, 53201, United States of America.
| | - Elizabeth Batsel
- Department of Biomedical Sciences, Marquette University, 53201, United States of America
| | - Pantelis Tsoulfas
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, United States of America
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Baylo-Marín O, Flores Á, García-Alías G. Long-term rehabilitation reduces task error variability in cervical spinal cord contused rats. Exp Neurol 2021; 348:113928. [PMID: 34813841 DOI: 10.1016/j.expneurol.2021.113928] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 10/27/2021] [Accepted: 11/16/2021] [Indexed: 11/28/2022]
Abstract
To promote skilled forelimb function following a spinal cord injury, we have evaluated whether long-term voluntary sensorimotor rehabilitation can promote substantial reaching and grasping recovery. Long-Evans rats were trained to reach single pellets and then received a moderate 100 kdyn contusion to the C5 lateral funiculi. During the first eight months post-injury, a group of animals was enrolled in daily skilled reaching rehabilitation consisting of grabbing and manipulating seeds from the bottom of a grid. Single-pellet reaching and grasping recovery was tested biweekly throughout the functional follow-up and the recovery was compared to a second group of contused but non-rehabilitated animals. Following the injury, reaching and grasping success dropped to zero in both groups and remained absent for three months post-injury, followed by a slight recovery that remained constant until the end of the follow-up. No differences in reaching success were found between groups. Nevertheless, the type of gesture errors in the failed attempts were categorized and scored. The errors ranged from the animal's inability to lift the paw and initiate the movement to the final stage of the attempt, in which the pellet falls during grasping and retraction of the paw towards the mouth. Both groups of animals exhibited similar types of errors but the animals with rehabilitation showed less error variability and those that occurred at the latest stages of the attempt predominated compared to those performed by the non-trained animals. Histological examination of the injury showed that injury severity was similar between groups and that the damage was circumscribed to the site of impact, affecting mainly the dorsal and medial region of the lateral funiculi, with preservation of the dorsal component of the corticospinal tract and the interneurons and motoneurons of the spinal segments beyond the site of injury. The results indicate that activity-dependent plasticity driven by voluntary rehabilitation decreases task error variability and drives the recovery of the movement gestures. However, the plasticity achieved is insufficient to attain full functional recovery to successfully reach, grasp and release the pellets in the mouth, indicating the necessity for additional interventional therapies to promote repair.
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Affiliation(s)
- Olaia Baylo-Marín
- Department of Cell Biology, Physiology and Immunology & Institute of Neuroscience, Universitat Autònoma de Barcelona, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
| | - África Flores
- Department of Cell Biology, Physiology and Immunology & Institute of Neuroscience, Universitat Autònoma de Barcelona, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
| | - Guillermo García-Alías
- Department of Cell Biology, Physiology and Immunology & Institute of Neuroscience, Universitat Autònoma de Barcelona, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain; Institut Guttmann de Neurorehabilitació, Badalona, Spain.
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8
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Ohri SS, Howard RM, Liu Y, Andres KR, Hetman M, Whittemore SR. Oligodendrocyte-specific deletion of Xbp1 exacerbates the endoplasmic reticulum stress response and restricts locomotor recovery after thoracic spinal cord injury. Glia 2021; 69:424-435. [PMID: 32926479 PMCID: PMC8931742 DOI: 10.1002/glia.23907] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 08/21/2020] [Accepted: 08/23/2020] [Indexed: 12/31/2022]
Abstract
The endoplasmic reticulum stress response (ERSR) is activated in various neurodegenerative diseases and/or after CNS traumatic injuries. The ERSR is comprised of three major arms, PERK, IRE-1, and activating transcription factor-6, with the latter two contributing to the unfolded protein response (UPR). PERK activity overlaps with the integrated stress response (ISR) kinases, PKR, HRI, and GCN2 which all signal through, eukaryotic initiation factor 2α, ATF4, and CHOP. All initially attempt to restore endoplasmic reticulum (ER) homeostasis, but if ER stress is unresolved, ATF4/CHOP-mediated cell death is initiated. Here, we investigate the contribution of the inositol-requiring protein-1α-X-box binding protein-1 (XBP1)-mediated UPR signaling pathway to the pathogenesis of spinal cord injury (SCI). We demonstrate that deletion of Xbp1 caused an exacerbated ATF4/CHOP signaling in cultured mouse oligodendrocyte (OL) progenitor cells and enhanced their sensitivity to ER stress. Similar effects were also observed with the Xbp1 pathway inhibitor toyocamycin. Furthermore, OL lineage-specific loss of Xbp1 resulted in enhanced ISR in mice that underwent moderate contusive SCI at the T9 level. Consistently, post-injury recovery of hindlimb locomotion and white matter sparing were reduced in OL Xbp1-deficient mice, which correlated with chronically decreased relative density of OPCs and OLs at the injury epicenter at 6 weeks post-SCI. We conclude that the IRE1-XBP1-mediated UPR signaling pathway contributes to restoration of ER homeostasis in OLs and is necessary for enhanced white matter sparing and functional recovery post-SCI.
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Affiliation(s)
- Sujata Saraswat Ohri
- Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, 511 S. Floyd St., MDR 616, Louisville, KY 40202, USA
- Departments of Neurological Surgery, University of Louisville, School of Medicine, 511 S. Floyd St., MDR 616, Louisville, KY 40202, USA
| | - Russell M. Howard
- Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, 511 S. Floyd St., MDR 616, Louisville, KY 40202, USA
- Departments of Neurological Surgery, University of Louisville, School of Medicine, 511 S. Floyd St., MDR 616, Louisville, KY 40202, USA
| | - Yu Liu
- Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, 511 S. Floyd St., MDR 616, Louisville, KY 40202, USA
- Departments of Neurological Surgery, University of Louisville, School of Medicine, 511 S. Floyd St., MDR 616, Louisville, KY 40202, USA
| | - Kariena R. Andres
- Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, 511 S. Floyd St., MDR 616, Louisville, KY 40202, USA
- Departments of Neurological Surgery, University of Louisville, School of Medicine, 511 S. Floyd St., MDR 616, Louisville, KY 40202, USA
| | - Michal Hetman
- Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, 511 S. Floyd St., MDR 616, Louisville, KY 40202, USA
- Departments of Neurological Surgery, University of Louisville, School of Medicine, 511 S. Floyd St., MDR 616, Louisville, KY 40202, USA
- Departments of Pharmacology & Toxicology, University of Louisville, School of Medicine, 511 S. Floyd St., MDR 616, Louisville, KY 40202, USA
- Departments of Anatomical Sciences & Neurobiology, University of Louisville, School of Medicine, 511 S. Floyd St., MDR 616, Louisville, KY 40202, USA
| | - Scott R. Whittemore
- Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, 511 S. Floyd St., MDR 616, Louisville, KY 40202, USA
- Departments of Neurological Surgery, University of Louisville, School of Medicine, 511 S. Floyd St., MDR 616, Louisville, KY 40202, USA
- Departments of Pharmacology & Toxicology, University of Louisville, School of Medicine, 511 S. Floyd St., MDR 616, Louisville, KY 40202, USA
- Departments of Anatomical Sciences & Neurobiology, University of Louisville, School of Medicine, 511 S. Floyd St., MDR 616, Louisville, KY 40202, USA
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Fouad K, Popovich PG, Kopp MA, Schwab JM. The neuroanatomical-functional paradox in spinal cord injury. Nat Rev Neurol 2021; 17:53-62. [PMID: 33311711 PMCID: PMC9012488 DOI: 10.1038/s41582-020-00436-x] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/11/2020] [Indexed: 12/13/2022]
Abstract
Although lesion size is widely considered to be the most reliable predictor of outcome after CNS injury, lesions of comparable size can produce vastly different magnitudes of functional impairment and subsequent recovery. This neuroanatomical-functional paradox is likely to contribute to the many failed attempts to independently replicate findings from animal models of neurotrauma. In humans, the analogous clinical-radiological paradox could explain why individuals with similar injuries can respond differently to rehabilitation. We describe the neuroanatomical-functional paradox in the context of traumatic spinal cord injury (SCI) and discuss the underlying mechanisms of the paradox, including the concepts of lesion-affected and recovery-related networks. We also consider the various secondary complications that further limit the accuracy of outcome prediction in SCI and provide suggestions for how to increase the predictive, translational value of preclinical SCI models.
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Affiliation(s)
- Karim Fouad
- Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
- Institute for Neuroscience and Mental Health, University of Alberta, Edmonton, AB, Canada
| | - Phillip G Popovich
- Belford Center for Spinal Cord Injury, The Ohio State University, Wexner Medical Center, Columbus, OH, USA
- Center for Brain and Spinal Cord Repair, The Ohio State University, Wexner Medical Center, Columbus, OH, USA
- Department of Neuroscience, The Ohio State University, Wexner Medical Center, Columbus, OH, USA
- The Neurological Institute, The Ohio State University, Wexner Medical Center, Columbus, OH, USA
| | - Marcel A Kopp
- Clinical & Experimental Spinal Cord Injury Research, Department of Neurology with Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health (QUEST-Center for Transforming Biomedical Research), Berlin, Germany
| | - Jan M Schwab
- Belford Center for Spinal Cord Injury, The Ohio State University, Wexner Medical Center, Columbus, OH, USA.
- Center for Brain and Spinal Cord Repair, The Ohio State University, Wexner Medical Center, Columbus, OH, USA.
- Department of Neuroscience, The Ohio State University, Wexner Medical Center, Columbus, OH, USA.
- The Neurological Institute, The Ohio State University, Wexner Medical Center, Columbus, OH, USA.
- Clinical & Experimental Spinal Cord Injury Research, Department of Neurology with Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany.
- Spinal Cord Injury Medicine (Neuroplegiology), Department of Neurology, The Ohio State University, Wexner Medical Center, Columbus, OH, USA.
- Department of Physical Medicine and Rehabilitation, The Ohio State University, Wexner Medical Center, Columbus, OH, USA.
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Pham BN, Luo J, Anand H, Kola O, Salcedo P, Nguyen C, Gaunt S, Zhong H, Garfinkel A, Tillakaratne N, Edgerton VR. Redundancy and multifunctionality among spinal locomotor networks. J Neurophysiol 2020; 124:1469-1479. [PMID: 32966757 PMCID: PMC8356786 DOI: 10.1152/jn.00338.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 08/26/2020] [Accepted: 09/13/2020] [Indexed: 02/08/2023] Open
Abstract
c-Fos is used to identify system-wide neural activation with cellular resolution in vivo. However, c-Fos can only capture neural activation of one event. Targeted recombination in active populations (TRAP) allows the capture of two different c-Fos activation patterns in the same animal. So far, TRAP has only been used to examine brain circuits. This study uses TRAP to investigate spinal circuit activation during resting and stepping, giving novel insights of network activation during these events. The level of colabeled (c-Fos+ and TRAP+) neurons observed after performing two bouts of stepping suggests that there is a probabilistic-like phenomenon that can recruit many combinations of neural populations (synapses) when repetitively generating many step cycles. Between two 30-min bouts of stepping, each consisting of thousands of steps, only ∼20% of the neurons activated from the first bout of stepping were also activated by the second bout. We also show colabeling of interneurons that have been active during stepping and resting. The use of the FosTRAP methodology in the spinal cord provides a new tool to compare the engagement of different populations of spinal interneurons in vivo under different motor tasks or under different conditions.NEW & NOTEWORTHY The results are consistent with there being an extensive amount of redundancy among spinal locomotor circuits. Using the newly developed FosTRAP mouse model, only ∼20% of neurons that were active (labeled by Fos-linked tdTomato expression) during a first bout of 30-min stepping were also labeled for c-Fos during a second bout of stepping. This finding suggests variability of neural networks that enables selection of many combinations of neurons (synapses) when generating each step cycle.
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Affiliation(s)
- Bau N. Pham
- Department of Bioengineering, University of California, Los Angeles, California
| | - Jiangyuan Luo
- Department of Neuroscience, University of California, Los Angeles, California
| | - Harnadar Anand
- Institute for Society and Genetics, University of California, Los Angeles, California
| | - Olivia Kola
- Department of Neuroscience, University of California, Los Angeles, California
| | - Pia Salcedo
- Department of Psychobiology, University of California, Los Angeles, California
| | - Connie Nguyen
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California
| | - Sarah Gaunt
- Department of Molecular Cellular and Developmental Biology, University of California, Los Angeles, California
| | - Hui Zhong
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California
| | - Alan Garfinkel
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California
| | - Niranjala Tillakaratne
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California
- Brain Research Institute, University of California, Los Angeles, California
| | - V. Reggie Edgerton
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California
- Brain Research Institute, University of California, Los Angeles, California
- Department of Neurobiology, University of California, Los Angeles, California
- Department of Neurosurgery, University of California, Los Angeles, California
- Institut Guttmann, Hospital de Neurorehabilitació, Universitat Autònoma de Barcelona, Badalona, Spain
- Centre for Neuroscience and Regenerative Medicine, Faculty of Science, University of Technology Sydney, Ultimo, Australia
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11
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Slomnicki LP, Myers SA, Saraswat Ohri S, Parsh MV, Andres KR, Chariker JH, Rouchka EC, Whittemore SR, Hetman M. Improved locomotor recovery after contusive spinal cord injury in Bmal1 -/- mice is associated with protection of the blood spinal cord barrier. Sci Rep 2020; 10:14212. [PMID: 32848194 PMCID: PMC7450087 DOI: 10.1038/s41598-020-71131-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 08/10/2020] [Indexed: 11/09/2022] Open
Abstract
The transcription factor BMAL1/ARNTL is a non-redundant component of the clock pathway that regulates circadian oscillations of gene expression. Loss of BMAL1 perturbs organismal homeostasis and usually exacerbates pathological responses to many types of insults by enhancing oxidative stress and inflammation. Surprisingly, we observed improved locomotor recovery and spinal cord white matter sparing in Bmal1-/- mice after T9 contusive spinal cord injury (SCI). While acute loss of neurons and oligodendrocytes was unaffected, Bmal1 deficiency reduced the chronic loss of oligodendrocytes at the injury epicenter 6 weeks post SCI. At 3 days post-injury (dpi), decreased expression of genes associated with cell proliferation, neuroinflammation and disruption of the blood spinal cord barrier (BSCB) was also observed. Moreover, intraspinal extravasation of fibrinogen and immunoglobulins was decreased acutely at dpi 1 and subacutely at dpi 7. Subacute decrease of hemoglobin deposition was also observed. Finally, subacutely reduced levels of the leukocyte marker CD45 and even greater reduction of the pro-inflammatory macrophage receptor CD36 suggest not only lower numbers of those cells but also their reduced inflammatory potential. These data indicate that Bmal1 deficiency improves SCI outcome, in part by reducing BSCB disruption and hemorrhage decreasing cytotoxic neuroinflammation and attenuating the chronic loss of oligodendrocytes.
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Affiliation(s)
- Lukasz P Slomnicki
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville, Louisville, KY, 40202, USA
| | - Scott A Myers
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville, Louisville, KY, 40202, USA
| | - Sujata Saraswat Ohri
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, 40202, USA.
- Department of Neurological Surgery, University of Louisville, Louisville, KY, 40202, USA.
- Kentucky Spinal Cord Injury Research Center, University of Louisville, 511 S. Floyd St., MDR616, Louisville, KY, 40292, USA.
| | - Molly V Parsh
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville, Louisville, KY, 40202, USA
| | - Kariena R Andres
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville, Louisville, KY, 40202, USA
| | - Julia H Chariker
- Department of Computer Engineering and Computer Science, University of Louisville, Louisville, KY, 40202, USA
- Kentucky Biomedical Research Infrastructure Network Bioinformatics Core, University of Louisville, Louisville, KY, 40202, USA
| | - Eric C Rouchka
- Department of Computer Engineering and Computer Science, University of Louisville, Louisville, KY, 40202, USA
- Kentucky Biomedical Research Infrastructure Network Bioinformatics Core, University of Louisville, Louisville, KY, 40202, USA
| | - Scott R Whittemore
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville, Louisville, KY, 40202, USA
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, 40202, USA
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY, 40202, USA
| | - Michal Hetman
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, 40202, USA.
- Department of Neurological Surgery, University of Louisville, Louisville, KY, 40202, USA.
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, 40202, USA.
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY, 40202, USA.
- Kentucky Spinal Cord Injury Research Center, University of Louisville, 511 S. Floyd St., MDR616, Louisville, KY, 40292, USA.
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12
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Pukos N, Goodus MT, Sahinkaya FR, McTigue DM. Myelin status and oligodendrocyte lineage cells over time after spinal cord injury: What do we know and what still needs to be unwrapped? Glia 2019; 67:2178-2202. [PMID: 31444938 DOI: 10.1002/glia.23702] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 07/29/2019] [Accepted: 07/30/2019] [Indexed: 01/04/2023]
Abstract
Spinal cord injury (SCI) affects over 17,000 individuals in the United States per year, resulting in sudden motor, sensory and autonomic impairments below the level of injury. These deficits may be due at least in part to the loss of oligodendrocytes and demyelination of spared axons as it leads to slowed or blocked conduction through the lesion site. It has long been accepted that progenitor cells form new oligodendrocytes after SCI, resulting in the acute formation of new myelin on demyelinated axons. However, the chronicity of demyelination and the functional significance of remyelination remain contentious. Here we review work examining demyelination and remyelination after SCI as well as the current understanding of oligodendrocyte lineage cell responses to spinal trauma, including the surprisingly long-lasting response of NG2+ oligodendrocyte progenitor cells (OPCs) to proliferate and differentiate into new myelinating oligodendrocytes for months after SCI. OPCs are highly sensitive to microenvironmental changes, and therefore respond to the ever-changing post-SCI milieu, including influx of blood, monocytes and neutrophils; activation of microglia and macrophages; changes in cytokines, chemokines and growth factors such as ciliary neurotrophic factor and fibroblast growth factor-2; glutamate excitotoxicity; and axon degeneration and sprouting. We discuss how these changes relate to spontaneous oligodendrogenesis and remyelination, the evidence for and against demyelination being an important clinical problem and if remyelination contributes to motor recovery.
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Affiliation(s)
- Nicole Pukos
- Neuroscience Graduate Program, Ohio State University, Columbus, Ohio.,Belford Center for Spinal Cord Injury, Ohio State University, Columbus, Ohio
| | - Matthew T Goodus
- Belford Center for Spinal Cord Injury, Ohio State University, Columbus, Ohio.,Department of Neuroscience, Wexner Medical Center, Ohio State University, Columbus, Ohio
| | - Fatma R Sahinkaya
- Neuroscience Graduate Program, Ohio State University, Columbus, Ohio
| | - Dana M McTigue
- Belford Center for Spinal Cord Injury, Ohio State University, Columbus, Ohio.,Department of Neuroscience, Wexner Medical Center, Ohio State University, Columbus, Ohio
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13
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Testing Pathological Variation of White Matter Tract in Adult Rats after Severe Spinal Cord Injury with MRI. BIOMED RESEARCH INTERNATIONAL 2018; 2018:4068156. [PMID: 30534561 PMCID: PMC6252222 DOI: 10.1155/2018/4068156] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 09/07/2018] [Accepted: 10/15/2018] [Indexed: 01/21/2023]
Abstract
The purpose of this study was to assess the pathological variation in white matter tracts in the adult severe thoracic contusion spinal cord injury (SCI) rat models combined with in vivo magnetic resonance imaging (MRI), as well as the effect of spared white matter (WM) quantity on hindlimb motor function recovery. 7.0T MRI was conducted for all experimental animals before SCI and 1, 3, 7, and 14 days after SCI. The variation in the white matter tract in different regions of the spinal cord after SCI was examined by luxol fast blue (LFB) staining, NF200 immunochemistry, and diffusion tensor imaging (DTI) parameters, including fraction anisotropy, mean diffusivity, axial diffusion, and radial diffusivity. Meanwhile, Basso-Beattie-Bresnahan (BBB) open-field scoring was performed to evaluate the behavior of the paraplegic hind limbs. The quantitative analysis showed that spared white matter measures assessed by LFB and MRI had a close correlation (R2 = 0.8508). The percentage of spared white matter area was closely correlated with BBB score (R2 = 0.8460). After SCI, spared white matter in the spinal cord, especially the ventral column WM, played a critical role in motor function restoration. The results suggest that the first three days provides a key time window for SCI protection and treatment; spared white matter, especially in the ventral column, plays a key role in motor function recovery in rats. Additionally, DTI may be an important noninvasive technique to diagnose acute SCI degree as well as a tool to evaluate functional prognosis. During the transition from nerve protection toward clinical treatment after SCI, in vivo DTI may serve as an emerging noninvasive technique to diagnose acute SCI degree and predict the degree of spontaneous functional recovery after SCI.
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14
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Following Spinal Cord Injury Transected Reticulospinal Tract Axons Develop New Collateral Inputs to Spinal Interneurons in Parallel with Locomotor Recovery. Neural Plast 2017; 2017:1932875. [PMID: 29138697 PMCID: PMC5613456 DOI: 10.1155/2017/1932875] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 07/06/2017] [Accepted: 07/30/2017] [Indexed: 12/19/2022] Open
Abstract
The reticulospinal tract (RtST) descends from the reticular formation and terminates in the spinal cord. The RtST drives the initiation of locomotion and postural control. RtST axons form new contacts with propriospinal interneurons (PrINs) after incomplete spinal cord injury (SCI); however, it is unclear if injured or uninjured axons make these connections. We completely transected all traced RtST axons in rats using a staggered model, where a hemisection SCI at vertebra T10 is followed by a contralateral hemisection at vertebra T7. In one group of the animals, the T7 SCI was performed 2 weeks after the T10 SCI (delayed; dSTAG), and in another group, the T10 and T7 SCIs were concomitant (cSTAG). dSTAG animals had significantly more RtST-PrIN contacts in the grey matter compared to cSTAG animals (p < 0.05). These results were accompanied by enhanced locomotor recovery with dSTAG animals significantly outperforming cSTAG animals (BBB test; p < 0.05). This difference suggests that activity in neuronal networks below the first SCI may contribute to enhanced recovery, because dSTAG rats recovered locomotor ability before the second hemisection. In conclusion, our findings support the hypothesis that the injured RtST forms new connections and is a key player in the recovery of locomotion post-SCI.
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15
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AAV-KLF7 Promotes Descending Propriospinal Neuron Axonal Plasticity after Spinal Cord Injury. Neural Plast 2017; 2017:1621629. [PMID: 28884027 PMCID: PMC5572611 DOI: 10.1155/2017/1621629] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/27/2017] [Accepted: 06/12/2017] [Indexed: 01/16/2023] Open
Abstract
DPSN axons mediate and maintain a variety of normal spinal functions. Unsurprisingly, DPSN tracts have been shown to mediate functional recovery following SCI. KLF7 could contribute to CST axon plasticity after spinal cord injury. In the present study, we assessed whether KLF7 could effectively promote DPSN axon regeneration and synapse formation following SCI. An AAV-KLF7 construct was used to overexpress KLF7. In vitro, KLF7 and target proteins were successfully elevated and axonal outgrowth was enhanced. In vivo, young adult C57BL/6 mice received a T10 contusion followed by an AAV-KLF7 injection at the T7–9 levels above the lesion. Five weeks later, overexpression of KLF7 was expressed in DPSN. KLF7 and KLF7 target genes (NGF, TrkA, GAP43, and P0) were detectably increased in the injured spinal cord. Myelin sparring at the lesion site, DPSN axonal regeneration and synapse formation, muscle weight, motor endplate morphology, and functional parameters were all additionally improved by KLF7 treatment. Our findings suggest that KLF7 promotes DPSN axonal plasticity and the formation of synapses with motor neurons at the caudal spinal cord, leading to improved functional recovery and further supporting the potential of AAV-KLF7 as a therapeutic agent for spinal cord injury.
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16
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Schaal SM, Kitay BM, Cho KS, Lo TP, Barakat DJ, Marcillo AE, Sanchez AR, Andrade CM, Pearse DD. Schwann Cell Transplantation Improves Reticulospinal Axon Growth and Forelimb Strength after Severe Cervical Spinal Cord Contusion. Cell Transplant 2017; 16:207-28. [PMID: 17503734 DOI: 10.3727/000000007783464768] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Schwann cell (SC) implantation alone has been shown to promote the growth of propriospinal and sensory axons, but not long-tract descending axons, after thoracic spinal cord injury (SCI). In the current study, we examined if an axotomy close to the cell body of origin (so as to enhance the intrinsic growth response) could permit supraspinal axons to grow onto SC grafts. Adult female Fischer rats received a severe (C5) cervical contusion (1.1 mm displacement, 3 KDyn). At 1 week postinjury, 2 million SCs ex vivo transduced with lentiviral vector encoding enhanced green fluorescent protein (EGFP) were implanted within media into the injury epicenter; injury-only animals served as controls. Animals were tested weekly using the BBB score for 7 weeks postimplantation and received at end point tests for upper body strength: self-supported forelimb hanging, forearm grip force, and the incline plane. Following behavioral assessment, animals were anterogradely traced bilaterally from the reticular formation using BDA-Texas Red. Stereological quantification revealed a twofold increase in the numbers of preserved NeuN+ neurons rostral and caudal to the injury/graft site in SC implanted animals, corroborating previous reports of their neuroprotective efficacy. Examination of labeled reticulospinal axon growth revealed that while rarely an axon was present within the lesion site of injury-only controls, numerous reticulospinal axons had penetrated the SC implant/lesion milieu. This has not been observed following implantation of SCs alone into the injured thoracic spinal cord. Significant behavioral improvements over injury-only controls in upper limb strength, including an enhanced grip strength (a 296% increase) and an increased self-supported forelimb hanging, accompanied SC-mediated neuroprotection and reticulospinal axon growth. The current study further supports the neuroprotective efficacy of SC implants after SCI and demonstrates that SCs alone are capable of supporting modest supraspinal axon growth when the site of axon injury is closer to the cell body of the axotomized neuron.
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Affiliation(s)
- S M Schaal
- The Miami Project to Cure Paralysis, University of Miami School of Medicine, Miami, FL 33101, USA
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17
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Nardone R, Florea C, Höller Y, Brigo F, Versace V, Lochner P, Golaszewski S, Trinka E. Rodent, large animal and non-human primate models of spinal cord injury. ZOOLOGY 2017; 123:101-114. [PMID: 28720322 DOI: 10.1016/j.zool.2017.06.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 06/02/2017] [Accepted: 06/02/2017] [Indexed: 01/05/2023]
Abstract
In this narrative review we aimed to assess the usefulness of the different animal models in identifying injury mechanisms and developing therapies for humans suffering from spinal cord injury (SCI). Results obtained from rodent studies are useful but, due to the anatomical, molecular and functional differences, confirmation of these findings in large animals or non-human primates may lead to basic discoveries that cannot be made in rodent models and that are more useful for developing treatment strategies in humans. SCI in dogs can be considered as intermediate between rodent models and human clinical trials, but the primate models could help to develop appropriate methods that might be more relevant to humans. Ideally, an animal model should meet the requirements of availability and repeatability as well as reproduce the anatomical features and the clinical pathological changing process of SCI. An animal model that completely simulates SCI in humans does not exist. The different experimental models of SCI have advantages and disadvantages for investigating the different aspects of lesion development, recovery mechanisms and potential therapeutic interventions. The potential advantages of non-human primate models include genetic similarities, similar caliber/length of the spinal cord as well as biological and physiological responses to injury which are more similar to humans. Among the potential disadvantages, high operating costs, infrastructural requirements and ethical concerns should be considered. The translation from experimental repair strategies to clinical applications needs to be investigated in future carefully designed studies.
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Affiliation(s)
- Raffaele Nardone
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Ignaz-Harrer-Str. 79, A-5020, Salzburg, Austria; Department of Neurology, Franz Tappeiner Hospital, Via Rossini 5, I-39012, Merano, Italy; Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Ignaz-Harrer-Str. 79, A-5020, Salzburg, Austria.
| | - Cristina Florea
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Ignaz-Harrer-Str. 79, A-5020, Salzburg, Austria
| | - Yvonne Höller
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Ignaz-Harrer-Str. 79, A-5020, Salzburg, Austria
| | - Francesco Brigo
- Department of Neurology, Franz Tappeiner Hospital, Via Rossini 5, I-39012, Merano, Italy; Department of Neurosciences, Biomedicine and Movement Sciences, Section of Clinical Neurology, University of Verona, Piazzale L.A. Scuro, I-37134 Verona, Italy
| | - Viviana Versace
- Department of Neurorehabilitation, Hospital of Vipiteno, Via Santa Margherita 24, I-39049, Italy
| | - Piergiorgio Lochner
- Department of Neurology, Saarland University Medical Center, Kirrberger-Str. 100, D-66421 Homburg, Germany
| | - Stefan Golaszewski
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Ignaz-Harrer-Str. 79, A-5020, Salzburg, Austria
| | - Eugen Trinka
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Ignaz-Harrer-Str. 79, A-5020, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Ignaz-Harrer-Str. 79, A-5020, Salzburg, Austria
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18
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Wu W, Xiong W, Zhang P, Chen L, Fang J, Shields C, Xu XM, Jin X. Increased threshold of short-latency motor evoked potentials in transgenic mice expressing Channelrhodopsin-2. PLoS One 2017; 12:e0178803. [PMID: 28562670 PMCID: PMC5451077 DOI: 10.1371/journal.pone.0178803] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 05/18/2017] [Indexed: 01/28/2023] Open
Abstract
Transgenic mice that express channelrhodopsin-2 or its variants provide a powerful tool for optogenetic study of the nervous system. Previous studies have established that introducing such exogenous genes usually does not alter anatomical, electrophysiological, and behavioral properties of neurons in these mice. However, in a line of Thy1-ChR2-YFP transgenic mice (line 9, Jackson lab), we found that short-latency motor evoked potentials (MEPs) induced by transcranial magnetic stimulation had a longer latency and much lower amplitude than that of wild type mice. MEPs evoked by transcranial electrical stimulation also had a much higher threshold in ChR2 mice, although similar amplitudes could be evoked in both wild and ChR2 mice at maximal stimulation. In contrast, long-latency MEPs evoked by electrically stimulating the motor cortex were similar in amplitude and latency between wild type and ChR2 mice. Whole-cell patch clamp recordings from layer V pyramidal neurons of the motor cortex in ChR2 mice revealed no significant differences in intrinsic membrane properties and action potential firing in response to current injection. These data suggest that corticospinal tract is not accountable for the observed abnormality. Motor behavioral assessments including BMS score, rotarod, and grid-walking test showed no significant differences between the two groups. Because short-latency MEPs are known to involve brainstem reticulospinal tract, while long-latency MEPs mainly involve primary motor cortex and dorsal corticospinal tract, we conclude that this line of ChR2 transgenic mice has normal function of motor cortex and dorsal corticospinal tract, but reduced excitability and responsiveness of reticulospinal tracts. This abnormality needs to be taken into account when using these mice for related optogenetic study.
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Affiliation(s)
- Wei Wu
- Department of Neurological Surgery, Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States of America.,Spinal Cord and Brain Injury Research Group, Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Wenhui Xiong
- Spinal Cord and Brain Injury Research Group, Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States of America.,Department of Anatomy and Cell Biology, Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Ping Zhang
- Norton Neuroscience Institute, Norton Healthcare, Louisville, Kentucky, United States of America
| | - Lifang Chen
- Department of Anatomy and Cell Biology, Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States of America.,Department of Acupuncture, Third Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang Province, China
| | - Jianqiao Fang
- Department of Acupuncture, Third Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang Province, China.,Zhejiang Chinese Medical University, Hangzhou, China
| | - Christopher Shields
- Norton Neuroscience Institute, Norton Healthcare, Louisville, Kentucky, United States of America
| | - Xiao-Ming Xu
- Department of Neurological Surgery, Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States of America.,Spinal Cord and Brain Injury Research Group, Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States of America.,Department of Anatomy and Cell Biology, Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Xiaoming Jin
- Department of Neurological Surgery, Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States of America.,Spinal Cord and Brain Injury Research Group, Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States of America.,Department of Anatomy and Cell Biology, Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
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19
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Park JH, Kim JH, Oh SK, Baek SR, Min J, Kim YW, Kim ST, Woo CW, Jeon SR. Analysis of equivalent parameters of two spinal cord injury devices: the New York University impactor versus the Infinite Horizon impactor. Spine J 2016; 16:1392-1403. [PMID: 27349631 DOI: 10.1016/j.spinee.2016.06.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 05/11/2016] [Accepted: 06/22/2016] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT The New York University (NYU) impactor and the Infinite Horizon (IH) impactor are used to create spinal cord injury (SCI) models. However, the parameters of these two devices that yield equivalent SCI severity remain unclear. PURPOSE To identify equivalent parameters, rats with SCIs induced by either device set at various parameters were subjected to behavioral and histologic analyses. STUDY DESIGN This is an animal laboratory study. METHODS Groups of eight rats acquired SCIs by dropping a 10 g rod from a height of 25 mm or 50 mm by using the NYU device or by delivering a force of 150 kdyn, 175 kdyn, 200 kdyn, or 250 kdyn by using the IH impactor. All injured rats were tested weekly for 8 weeks by using the Basso, Beattie, and Bresnahan (BBB) test and the ladder rung test. On the 10th week, the lesion volume of each group was measured by using a 9.4 Tesla magnetic resonance imaging (MRI), and the spinal cords were subjected to histologic analysis using anterograde biotinylated dextran amine (BDA) tracing and immunofluorescence staining with an anti-protein kinase C-gamma (PKC-γ) antibody. RESULTS Basso, Beattie, and Bresnahan test scores between the 25 mm and the 200 kdyn groups as well as between the 50 mm and and 250 kdyn groups were very similar. Although it was not statistically significant, the mean scores of the ladder rung test in the 200 kdyn group were higher than the 25 mm group at all assessment time points. There was a significantly different cavity volume only between the 50 mm and the 200 kdyn groups. Midline sagittal images of the spinal cord on the MRI revealed that the 25 mm group predominantly had dorsal injuries, whereas the 200 kdyn group had deeper injuries. Anterograde tracing with BDA showed that in the 200 kdyn group, the dorsal corticospinal tract of the caudal area of the lesion was labeled. Similar labeling was not observed in the 25 mm group. Immunofluorescence staining of PKC-γ also revealed strong staining of the dorsal corticospinal tract in the 200 kdyn group but not in the 25 mm group. CONCLUSIONS The 25 mm injuries generated by the NYU impactor are generally equivalent to the 200 kdyn injuries generated by using the IH impactor. However, differences in the ladder rung test scores, MRI images, BDA traces, and PKC-γ staining demonstrate that the two devices exert qualitatively different impacts on the spinal cord.
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Affiliation(s)
- Jin Hoon Park
- Department of Neurological Surgery, Gangneung Asan Hospital, University of Ulsan College of Medicine, Bangdong-gil, 38, Sacheon-myun, Gangneung, Republic of Korea
| | - Jeong Hoon Kim
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea
| | - Sun-Kyu Oh
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea
| | - Se Rim Baek
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea
| | - Joongkee Min
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea
| | - Yong Whan Kim
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Sang Tae Kim
- Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea
| | - Chul-Woong Woo
- Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea
| | - Sang Ryong Jeon
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea.
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20
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Early application of tail nerve electrical stimulation-induced walking training promotes locomotor recovery in rats with spinal cord injury. Spinal Cord 2016; 54:942-946. [PMID: 27067652 PMCID: PMC5399155 DOI: 10.1038/sc.2016.30] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 01/07/2016] [Accepted: 01/14/2016] [Indexed: 01/16/2023]
Abstract
Study design: This is a randomized controlled prospective trial with two parallel groups. Objectives: The objective of this study was to determine whether early application of tail nerve electrical stimulation (TANES)-induced walking training can improve the locomotor function. Setting: This study was conducted in SCS Research Center in Colorado, USA. Methods: A contusion injury to spinal cord T10 was produced using the New York University impactor device with a 25 -mm height setting in female, adult Long–Evans rats. Injured rats were randomly divided into two groups (n=12 per group). One group was subjected to TANES-induced walking training 2 weeks post injury, and the other group, as control, received no TANES-induced walking training. Restorations of behavior and conduction were assessed using the Basso, Beattie and Bresnahan open-field rating scale, horizontal ladder rung walking test and electrophysiological test (Hoffmann reflex). Results: Early application of TANES-induced walking training significantly improved the recovery of locomotor function and benefited the restoration of Hoffmann reflex. Conclusion: TANES-induced walking training is a useful method to promote locomotor recovery in rats with spinal cord injury.
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21
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Snider S, Cavalli A, Colombo F, Gallotti AL, Quattrini A, Salvatore L, Madaghiele M, Terreni MR, Sannino A, Mortini P. A novel composite type I collagen scaffold with micropatterned porosity regulates the entrance of phagocytes in a severe model of spinal cord injury. J Biomed Mater Res B Appl Biomater 2016; 105:1040-1053. [PMID: 26958814 DOI: 10.1002/jbm.b.33645] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 01/29/2016] [Accepted: 02/12/2016] [Indexed: 01/28/2023]
Abstract
Traumatic spinal cord injury (SCI) is a damage to the spinal cord that results in loss or impaired motor and/or sensory function. SCI is a sudden and unexpected event characterized by high morbidity and mortality rate during both acute and chronic stages, and it can be devastating in human, social and economical terms. Despite significant progresses in the clinical management of SCI, there remain no effective treatments to improve neurological outcomes. Among experimental strategies, bioengineered scaffolds have the potential to support and guide injured axons contributing to neural repair. The major aim of this study was to investigate a novel composite type I collagen scaffold with micropatterned porosity in a rodent model of severe spinal cord injury. After segment resection of the thoracic spinal cord we implanted the scaffold in female Sprague-Dawley rats. Controls were injured without receiving implantation. Behavioral analysis of the locomotor performance was monitored up to 55 days postinjury. Two months after injury histopathological analysis were performed to evaluate the extent of scar and demyelination, the presence of connective tissue and axonal regrowth through the scaffold and to evaluate inflammatory cell infiltration at the injured site. We provided evidence that the new collagen scaffold was well integrated with the host tissue, slightly ameliorated locomotor function, and limited the robust recruitment of the inflammatory cells at the injury site during both the acute and chronic stage in spinal cord injured rats. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1040-1053, 2017.
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Affiliation(s)
- Silvia Snider
- Division of Neurosurgery, San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy
| | - Andrea Cavalli
- Division of Neurosurgery, San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy
| | - Francesca Colombo
- Division of Neurosurgery, San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy
| | - Alberto Luigi Gallotti
- Division of Neurosurgery, San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy
| | - Angelo Quattrini
- Division of Neuroscience and INSPE, San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy
| | - Luca Salvatore
- Department of Engineering for Innovation, University of Salento, Via per Monteroni, 73100, Lecce, Italy
| | - Marta Madaghiele
- Department of Engineering for Innovation, University of Salento, Via per Monteroni, 73100, Lecce, Italy
| | - Maria Rosa Terreni
- Division of Pathology, San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy
| | - Alessandro Sannino
- Department of Engineering for Innovation, University of Salento, Via per Monteroni, 73100, Lecce, Italy
| | - Pietro Mortini
- Division of Neurosurgery, San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy
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22
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Leszczyńska AN, Majczyński H, Wilczyński GM, Sławińska U, Cabaj AM. Thoracic Hemisection in Rats Results in Initial Recovery Followed by a Late Decrement in Locomotor Movements, with Changes in Coordination Correlated with Serotonergic Innervation of the Ventral Horn. PLoS One 2015; 10:e0143602. [PMID: 26606275 PMCID: PMC4659566 DOI: 10.1371/journal.pone.0143602] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 11/06/2015] [Indexed: 11/18/2022] Open
Abstract
Lateral thoracic hemisection of the rodent spinal cord is a popular model of spinal cord injury, in which the effects of various treatments, designed to encourage locomotor recovery, are tested. Nevertheless, there are still inconsistencies in the literature concerning the details of spontaneous locomotor recovery after such lesions, and there is a lack of data concerning the quality of locomotion over a long time span after the lesion. In this study, we aimed to address some of these issues. In our experiments, locomotor recovery was assessed using EMG and CatWalk recordings and analysis. Our results showed that after hemisection there was paralysis in both hindlimbs, followed by a substantial recovery of locomotor movements, but even at the peak of recovery, which occurred about 4 weeks after the lesion, some deficits of locomotion remained present. The parameters that were abnormal included abduction, interlimb coordination and speed of locomotion. Locomotor performance was stable for several weeks, but about 3-4 months after hemisection secondary locomotor impairment was observed with changes in parameters, such as speed of locomotion, interlimb coordination, base of hindlimb support, hindlimb abduction and relative foot print distance. Histological analysis of serotonergic innervation at the lumbar ventral horn below hemisection revealed a limited restoration of serotonergic fibers on the ipsilateral side of the spinal cord, while on the contralateral side of the spinal cord it returned to normal. In addition, the length of these fibers on both sides of the spinal cord correlated with inter- and intralimb coordination. In contrast to data reported in the literature, our results show there is not full locomotor recovery after spinal cord hemisection. Secondary deterioration of certain locomotor functions occurs with time in hemisected rats, and locomotor recovery appears partly associated with reinnervation of spinal circuitry by serotonergic fibers.
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Affiliation(s)
| | | | | | | | - Anna M Cabaj
- Nencki Insitute of Experimental Biology, PAS, Warsaw, Poland.,Nałęcz Institute of Biocybernetics and Biomedical Engineering, PAS, Warsaw, Poland
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23
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Zhu Q, Tan Z, Zhao S, Huang H, Zhao X, Hu X, Zhang Y, Shields CB, Uetani N, Qiu M. Developmental expression and function analysis of protein tyrosine phosphatase receptor type D in oligodendrocyte myelination. Neuroscience 2015; 308:106-14. [PMID: 26341907 PMCID: PMC4600676 DOI: 10.1016/j.neuroscience.2015.08.062] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 08/13/2015] [Accepted: 08/24/2015] [Indexed: 11/22/2022]
Abstract
Receptor protein tyrosine phosphatases (RPTPs) are extensively expressed in the central nervous system (CNS), and have distinct spatial and temporal patterns in different cell types during development. Previous studies have demonstrated possible roles for RPTPs in axon outgrowth, guidance, and synaptogenesis. In the present study, our results revealed that protein tyrosine phosphatase, receptor type D (PTPRD) was initially expressed in mature neurons in embryonic CNS, and later in oligodendroglial cells at postnatal stages when oligodendrocytes undergo active axonal myelination process. In PTPRD mutants, oligodendrocyte differentiation was normal and a transient myelination delay occurred at early postnatal stages, indicating the contribution of PTPRD to the initiation of axonal myelination. Our results also showed that the remyelination process was not affected in the absence of PTPRD function after a cuprizone-induced demyelination in adult animals.
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Affiliation(s)
- Q Zhu
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY 40292, USA
| | - Z Tan
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY 40292, USA; Institute of Developmental and Regenerative Biology, Zhejiang Key Lab of Organ Development and Regeneration, College of Life Sciences, Hangzhou Normal University, China
| | - S Zhao
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY 40292, USA
| | - H Huang
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY 40292, USA; Institute of Developmental and Regenerative Biology, Zhejiang Key Lab of Organ Development and Regeneration, College of Life Sciences, Hangzhou Normal University, China
| | - X Zhao
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY 40292, USA; Institute of Developmental and Regenerative Biology, Zhejiang Key Lab of Organ Development and Regeneration, College of Life Sciences, Hangzhou Normal University, China
| | - X Hu
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY 40292, USA
| | - Y Zhang
- Norton Neuroscience Institute, Norton Healthcare, Louisville, KY 40202, USA
| | - C B Shields
- Norton Neuroscience Institute, Norton Healthcare, Louisville, KY 40202, USA
| | - N Uetani
- McGill Cancer Centre and Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - M Qiu
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY 40292, USA; Institute of Developmental and Regenerative Biology, Zhejiang Key Lab of Organ Development and Regeneration, College of Life Sciences, Hangzhou Normal University, China.
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Ahmad AS, Satriotomo I, Fazal J, Nadeau SE, Doré S. Considerations for the Optimization of Induced White Matter Injury Preclinical Models. Front Neurol 2015; 6:172. [PMID: 26322013 PMCID: PMC4532913 DOI: 10.3389/fneur.2015.00172] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 07/20/2015] [Indexed: 11/13/2022] Open
Abstract
White matter (WM) injury in relation to acute neurologic conditions, especially stroke, has remained obscure until recently. Current advances in imaging technologies in the field of stroke have confirmed that WM injury plays an important role in the prognosis of stroke and suggest that WM protection is essential for functional recovery and post-stroke rehabilitation. However, due to the lack of a reproducible animal model of WM injury, the pathophysiology and mechanisms of this injury are not well studied. Moreover, producing selective WM injury in animals, especially in rodents, has proven to be challenging. Problems associated with inducing selective WM ischemic injury in the rodent derive from differences in the architecture of the brain, most particularly, the ratio of WM to gray matter in rodents compared to humans, the agents used to induce the injury, and the location of the injury. Aging, gender differences, and comorbidities further add to this complexity. This review provides a brief account of the techniques commonly used to induce general WM injury in animal models (stroke and non-stroke related) and highlights relevance, optimization issues, and translational potentials associated with this particular form of injury.
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Affiliation(s)
- Abdullah Shafique Ahmad
- Department of Anesthesiology, Center for Translational Research in Neurodegenerative Disease, University of Florida , Gainesville, FL , USA
| | - Irawan Satriotomo
- Department of Anesthesiology, Center for Translational Research in Neurodegenerative Disease, University of Florida , Gainesville, FL , USA
| | - Jawad Fazal
- Department of Anesthesiology, Center for Translational Research in Neurodegenerative Disease, University of Florida , Gainesville, FL , USA
| | - Stephen E Nadeau
- Research Service, Brain Rehabilitation Research Center, Malcom Randall Veterans Affairs Medical Center , Gainesville, FL , USA ; Department of Neurology, University of Florida , Gainesville, FL , USA
| | - Sylvain Doré
- Department of Anesthesiology, Center for Translational Research in Neurodegenerative Disease, University of Florida , Gainesville, FL , USA ; Research Service, Brain Rehabilitation Research Center, Malcom Randall Veterans Affairs Medical Center , Gainesville, FL , USA ; Department of Neurology, University of Florida , Gainesville, FL , USA ; Department of Neuroscience, University of Florida , Gainesville, FL , USA ; Department of Neurology, University of Florida , Gainesville, FL , USA ; Department of Pharmaceutics, University of Florida , Gainesville, FL , USA ; Department of Psychology, University of Florida , Gainesville, FL , USA ; Department of Psychiatry, University of Florida , Gainesville, FL , USA
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25
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Kim JH, Song SK, Haldar JP. Signal-to-noise ratio-enhancing joint reconstruction for improved diffusion imaging of mouse spinal cord white matter injury. Magn Reson Med 2015; 75:852-8. [PMID: 25824472 DOI: 10.1002/mrm.25691] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 02/16/2015] [Accepted: 02/17/2015] [Indexed: 11/08/2022]
Abstract
PURPOSE To assess the capability of signal-to-noise ratio enhancing reconstruction (SER) to reduce the acquisition time for quantitative white matter injury assessment. METHODS Four single-average diffusion tensor imaging (DTI) datasets were acquired for each animal from four mouse cohorts: two models of spinal cord injury and two control groups. Quantitative parameters (apparent diffusion coefficient, relative anisotropy, axial and radial diffusivities) were computed from (I) single-average data with traditional reconstruction; (II) single-average data with SER; (III) four-average data with traditional reconstruction; and (IV) single-average data with optimized multicomponent nonlocal means (OMNLM) denoising. These approaches were compared based on coefficients of variation (COVs) and whether estimated diffusion parameters were sensitive to injury. RESULTS SER yielded better COVs for diffusivity and anisotropy than traditional reconstruction of single-average data, and yielded comparable COVs to that achieved with four-average data. In addition, diffusion parameters obtained using SER with single-average data had comparable injury sensitivity to those obtained from four-average data, while diffusion parameters obtained from OMNLM and traditional reconstruction of single-average data had limited sensitivity. CONCLUSION A four-fold reduction in the number of averages for quantitative diffusion imaging of small animal white matter injury is feasible using SER. Our results also underscore the need to validate nonlinear methods using task-based measures on an application-by-application basis.
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Affiliation(s)
- Joong Hee Kim
- Department of Radiology, Washington University, St. Louis, Missouri, USA
| | - Sheng-Kwei Song
- Department of Radiology, Washington University, St. Louis, Missouri, USA
| | - Justin P Haldar
- Departments of Electrical Engineering and Biomedical Engineering, University of Southern California, Los Angeles, California, USA
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26
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Zhang Y, Zhang YP, Pepinsky B, Huang G, Shields LBE, Shields CB, Mi S. Inhibition of LINGO-1 promotes functional recovery after experimental spinal cord demyelination. Exp Neurol 2015; 266:68-73. [PMID: 25681574 DOI: 10.1016/j.expneurol.2015.02.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 01/15/2015] [Accepted: 02/05/2015] [Indexed: 10/24/2022]
Abstract
Blocking LINGO-1 has been shown to enhance remyelination in the rat lysolecithin-induced focal spinal cord demyelination model. We used transcranial magnetic motor-evoked potentials (tcMMEPs) to assess the effect of blocking LINGO-1 on recovery of axonal function in a mouse lysolecithin model at 1, 2 and 4weeks after injury. The role of LINGO-1 was assessed using LINGO-1 knockout (KO) mice and in wild-type mice after intraperitoneal administration of anti-LINGO-1 antagonist monoclonal antibody (mAb3B5). Response rates (at 2 and 4weeks) and amplitudes (at 4weeks) were significantly increased in LINGO-1 KO and mAb3B5-treated mice compared with matched controls. The latency of potentials at 4weeks was significantly shorter in mAb3B5-treated mice compared with controls. Lesion areas in LINGO-1 KO and mAb3B5-treated mice were reduced significantly compared with matched controls. The number of remyelinated axons within the lesions was increased and the G-ratios of the axons were decreased in both LINGO-1 KO and mAb3B5-treated mice compared with matched controls. These data provide morphometric and functional evidence of enhancement of remyelination associated with antagonism of LINGO-1.
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Affiliation(s)
- Yongjie Zhang
- Department of Human Anatomy, Nanjing Medical University, 140 Hanzhong Road, Nanjing, Jiangsu Province 210029, China.
| | - Yi Ping Zhang
- Norton Neuroscience Institute, Norton Healthcare, 210 E. Gray Street, Suite 1102, Louisville, KY 40202, USA.
| | - Blake Pepinsky
- Department of Discovery Biology, Biogen Idec Inc., 14 Cambridge Center, Cambridge, MA 02142, USA.
| | - Guanrong Huang
- Department of Discovery Biology, Biogen Idec Inc., 14 Cambridge Center, Cambridge, MA 02142, USA.
| | - Lisa B E Shields
- Norton Neuroscience Institute, Norton Healthcare, 210 E. Gray Street, Suite 1102, Louisville, KY 40202, USA.
| | - Christopher B Shields
- Norton Neuroscience Institute, Norton Healthcare, 210 E. Gray Street, Suite 1102, Louisville, KY 40202, USA.
| | - Sha Mi
- Department of Discovery Biology, Biogen Idec Inc., 14 Cambridge Center, Cambridge, MA 02142, USA.
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27
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Translation of the rat thoracic contusion model; part 2 — forward versus backward locomotion testing. Spinal Cord 2014; 52:529-35. [DOI: 10.1038/sc.2014.73] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 04/06/2014] [Accepted: 04/08/2014] [Indexed: 12/23/2022]
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28
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Behavioral and anatomical consequences of repetitive mild thoracic spinal cord contusion injury in the rat. Exp Neurol 2014; 257:57-69. [PMID: 24786492 DOI: 10.1016/j.expneurol.2014.04.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 03/19/2014] [Accepted: 04/20/2014] [Indexed: 01/21/2023]
Abstract
Moderate and severe spinal cord contusion injuries have been extensively studied, yet much less is known about mild injuries. Mild contusions result in transient functional deficits, proceeding to near-complete recovery, but they may render the spinal cord vulnerable to future injuries. However, to date there have been no appropriate models to study the behavioral consequences, anatomical changes, and susceptibility of a mild contusion to repeated injuries, which may occur in children as well as adults during competitive sport activities. We have developed a novel mild spinal cord contusion injury model characterized by a sequence of transient functional deficits after the first injury and restoration to near-complete motor and sensory function, which is then followed up by a second injury. This model can serve not only to study the effects of repeated injuries on behavioral and anatomical changes, but also to examine the relationship between successive tissue damage and recovery of function. In the present study, we confirmed that mild thoracic spinal cord contusion, utilizing the NYU impactor device, resulted in localized tissue damage, characterized by a cystic cavity and peripheral rim of spared white matter at the injury epicenter, and rapid functional recovery to near-normal levels utilizing several behavioral tests. Repeated injury after 3weeks, when functional recovery has been completed, resulted in worsening of both motor and sensory function, which did not recover to prior levels. Anatomical analyses showed no differences in the volumes of spared white matter, lesion, or cyst, but revealed modest extension of lesion area rostral to the injury epicenter as well as an increase in inflammation and apoptosis. These studies demonstrate that a mild injury model can be used to test efficacy of treatments for repeated injuries and may serve to assist in the formulation of policies and clinical practice regarding mild SCI injury and spinal concussion.
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29
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Torres-Espín A, Redondo-Castro E, Hernández J, Navarro X. Bone marrow mesenchymal stromal cells and olfactory ensheathing cells transplantation after spinal cord injury--a morphological and functional comparison in rats. Eur J Neurosci 2014; 39:1704-17. [PMID: 24635194 DOI: 10.1111/ejn.12542] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 02/04/2014] [Indexed: 12/13/2022]
Abstract
Cell therapy for spinal cord injury (SCI) is a promising strategy for clinical application. Both bone marrow mesenchymal stromal cells (MSCs; also known as bone marrow-derived 'mesenchymal stem cells') and olfactory ensheathing cells (OECs) have demonstrated beneficial effects following transplantation in animal models of SCI. However, due to the large number of affecting parameters that determine the therapy success and the lack of methodological consensus, the comparison of different works is difficult. Therefore, we compared the effects of MSC and OEC transplants at early or delayed time after a spinal cord contusion injury in the rat. Functional outcomes for locomotion, sensory perception and electrophysiological responses were assessed. Moreover, the grafted cells survival and the amount of cavity and spared tissue were studied. The findings indicate that grafted cells survived until 7 days post-injection, but markedly disappeared in the following 2 weeks. Despite the low survival of the cells, MSC and OEC grafts provided tissue protection after early and delayed transplantation. Nevertheless, only acute MSC grafts improved locomotion recovery in treadmill condition and electrophysiological outcomes with respect to the other injured groups. These results, together with previous works, indicate that the MSC seem a better option than OEC for treatment of contusion injuries.
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Affiliation(s)
- Abel Torres-Espín
- Department of Cell Biology, Physiology and Immunology, Group of Neuroplasticity and Regeneration, Institute of Neurosciences, Edif. M, Universitat Autònoma de Barcelona, Bellaterra, E-08193, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
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30
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Walker CL, Xu XM. PTEN inhibitor bisperoxovanadium protects oligodendrocytes and myelin and prevents neuronal atrophy in adult rats following cervical hemicontusive spinal cord injury. Neurosci Lett 2014; 573:64-8. [PMID: 24582904 DOI: 10.1016/j.neulet.2014.02.039] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 02/13/2014] [Accepted: 02/15/2014] [Indexed: 12/21/2022]
Abstract
Cervical spinal cord injury (SCI) damages axons and motor neurons responsible for ipsilateral forelimb function and causes demyelination and oligodendrocyte death. Inhibition of the phosphatase and tensin homologue, PTEN, promotes neural cell survival, neuroprotection and regeneration in vivo and in vitro. PTEN inhibition can also promote oligodendrocyte-mediated myelination of axons in vitro likely through Akt activation. We recently demonstrated that acute treatment with phosphatase PTEN inhibitor, bisperoxovanadium (bpV)-pic reduced tissue damage, neuron death, and promoted functional recovery after cervical hemi-contusion SCI. Evidence suggests bpV can promote myelin stability; however, bpV effects on myelination and oligodendrocytes in contusive SCI models are unclear. We hypothesized that bpV could increase myelin around the injury site through sparing or remyelination, and that bpV treatment may promote increased numbers of oligodendrocytes. Using histological and immunofluorescence labeling, we found that bpV treatment promoted significant spared white matter (30%; p<0.01) and relative Luxol Fast Blue (LFB)(+) myelin area rostral (Veh: 0.56 ± 0.01 vs. bpV: 0.64 ± 0.02; p<0.05) and at the epicenter (Veh: 0.42 ± 0.03 vs. bpV: 0.54 ± 0.03; p<0.05). VLF oligodendrocytes were also significantly greater with bpV therapy (109 ± 5.3 vs. Veh: 77 ± 2.7 mm(-2); p<0.01). In addition, bpV increased mean motor neuron soma area versus vehicle-treatment (1.0 ± 0.02 vs. Veh: 0.77 ± 0.02) relative to Sham neuron size. This study provides key insight into additional cell and tissue effects that could contribute to bpV-mediated functional recovery observed after contusive cervical SCI.
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Affiliation(s)
- Chandler L Walker
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, 950 W. Walnut Street, R2 Building, Room 402, Indianapolis, IN 46202, USA; Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Anatomy and Cell Biology, Indiana University School of Medicine, 950 W. Walnut Street, R2 Building, Room 402, Indianapolis, IN 46202, USA.
| | - Xiao-Ming Xu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, 950 W. Walnut Street, R2 Building, Room 402, Indianapolis, IN 46202, USA; Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Anatomy and Cell Biology, Indiana University School of Medicine, 950 W. Walnut Street, R2 Building, Room 402, Indianapolis, IN 46202, USA.
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Silva NA, Sousa N, Reis RL, Salgado AJ. From basics to clinical: a comprehensive review on spinal cord injury. Prog Neurobiol 2013; 114:25-57. [PMID: 24269804 DOI: 10.1016/j.pneurobio.2013.11.002] [Citation(s) in RCA: 526] [Impact Index Per Article: 47.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 11/12/2013] [Accepted: 11/12/2013] [Indexed: 12/15/2022]
Abstract
Spinal cord injury (SCI) is a devastating neurological disorder that affects thousands of individuals each year. Over the past decades an enormous progress has been made in our understanding of the molecular and cellular events generated by SCI, providing insights into crucial mechanisms that contribute to tissue damage and regenerative failure of injured neurons. Current treatment options for SCI include the use of high dose methylprednisolone, surgical interventions to stabilize and decompress the spinal cord, and rehabilitative care. Nonetheless, SCI is still a harmful condition for which there is yet no cure. Cellular, molecular, rehabilitative training and combinatorial therapies have shown promising results in animal models. Nevertheless, work remains to be done to ascertain whether any of these therapies can safely improve patient's condition after human SCI. This review provides an extensive overview of SCI research, as well as its clinical component. It starts covering areas from physiology and anatomy of the spinal cord, neuropathology of the SCI, current clinical options, neuronal plasticity after SCI, animal models and techniques to assess recovery, focusing the subsequent discussion on a variety of promising neuroprotective, cell-based and combinatorial therapeutic approaches that have recently moved, or are close, to clinical testing.
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Affiliation(s)
- Nuno A Silva
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Rui L Reis
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal; 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, 4806-909 Caldas das Taipas, Guimarães, Portugal
| | - António J Salgado
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
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Cai J, Zhang YP, Shields LBE, Zhang ZZ, Liu N, Xu XM, Feng SQ, Shields CB. Correlation between electrophysiological properties, morphological maturation, and olig gene changes during postnatal motor tract development. Dev Neurobiol 2013; 73:713-22. [PMID: 23696057 DOI: 10.1002/dneu.22094] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 05/13/2013] [Accepted: 05/14/2013] [Indexed: 11/05/2022]
Abstract
This study investigated electrophysiological and histological changes as well as alterations of myelin relevant proteins of descending motor tracts in rat pups. Motor-evoked potentials (MEPs) represent descending conducting responses following stimulation of the motor cortex to responses being elicited from the lower extremities. MEP responses were recorded biweekly from postnatal (PN) week 1 to week 9 (adult). MEP latencies in PN week 1 rats averaged 23.7 ms and became shorter during early maturation, stabilizing at 6.6 ms at PN week 4. During maturation, the conduction velocity (CV) increased from 2.8 ± 0.2 at PN week 1 to 35.2 ± 3.1 mm/ms at PN week 8. Histology of the spinal cord and sciatic nerves revealed progressive axonal myelination. Expression of the oligodendrocyte precursor markers PDGFRα and NG2 were downregulated in spinal cords, and myelin-relevant proteins such as GalC, CNP, and MBP increased during maturation. Oligodendrocyte-lineage markers Olig2 and MOG, expressed in myelinated oligodendrocytes, peaked at PN week 3 and were downregulated thereafter. A similar expression pattern was observed in neurofilament M/H subunits that were extensively phosphorylated in adult spinal cords but not in neonatal spinal cords, suggesting an increase in axon diameter and myelin formation. Ultrastructural morphology in the ventrolateral funiculus (VLF) showed axon myelination of the VLF axons (99.3%) at PN week 2, while 44.6% were sheathed at PN week 1. Increased axon diameter and myelin thickness in the VLF and sciatic nerves were highly correlated to the CV (rs > 0.95). This suggests that MEPs could be a predicator of morphological maturity of myelinated axons in descending motor tracts.
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Affiliation(s)
- Jun Cai
- Departments of Pediatrics and Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
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Rangasamy SB. Locomotor recovery after spinal cord hemisection/contusion injures in bonnet monkeys: footprint testing--a minireview. Synapse 2013; 67:427-53. [PMID: 23401170 DOI: 10.1002/syn.21645] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 02/01/2013] [Indexed: 12/12/2022]
Abstract
Spinal cord injuries usually produce loss or impairment of sensory, motor and reflex function below the level of damage. In the absence of functional regeneration or manipulations that promote regeneration, spontaneous improvements in motor functions occur due to the activation of multiple compensatory mechanisms in animals and humans following the partial spinal cord injury. Many studies were performed on quantitative evaluation of locomotor recovery after induced spinal cord injury in animals using behavioral tests and scoring techniques. Although few studies on rodents have led to clinical trials, it would appear imperative to use nonhuman primates such as macaque monkeys in order to relate the research outcomes to recovery of functions in humans. In this review, we will discuss some of our research evidences concerning the degree of spontaneous recovery in bipedal locomotor functions of bonnet monkeys that underwent spinal cord hemisection/contusion lesions. To our knowledge, this is the first report to discuss on the extent of spontaneous recovery in bipedal locomotion of macaque monkeys through the application of footprint analyzing technique. In addition, the results obtained were compared with the published data on recovery of quadrupedal locomotion of spinally injured rodents. We propose that the mechanisms underlying spontaneous recovery of functions in spinal cord lesioned monkeys may be correlated to the mature function of spinal pattern generator for locomotion under the impact of residual descending and afferent connections. Moreover, based on analysis of motor functions observed in locomotion in these subjected monkeys, we understand that spinal automatism and development of responses by afferent stimuli from outside the cord could possibly contribute to recovery of paralyzed hindlimbs. This report also emphasizes the functional contribution of progressive strengthening of undamaged nerve fibers through a collateral sprouts/synaptic plasticity formed in partially lesioned cord of monkeys.
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Affiliation(s)
- Suresh Babu Rangasamy
- Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois, 60612, USA.
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Kuypers NJ, James KT, Enzmann GU, Magnuson DSK, Whittemore SR. Functional consequences of ethidium bromide demyelination of the mouse ventral spinal cord. Exp Neurol 2013; 247:615-22. [PMID: 23466931 DOI: 10.1016/j.expneurol.2013.02.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 02/19/2013] [Accepted: 02/25/2013] [Indexed: 02/08/2023]
Abstract
Ethidium bromide (EB) has been extensively used in the rat as a model of spinal cord demyelination. However, this lesion has not been addressed in the adult mouse, a model with unlimited genetic potential. Here we characterize behavioral function, inflammation, myelin status and axonal viability following bilateral injection of 0.20 mg/mL ethidium bromide or saline into the ventral white matter (VWM) of female C57Bl/6 mice. EB-induced VWM demyelination significantly reduced spared VWM and Basso Mouse Scale (BMS) scores persisting out to 2 months. Chronic hindlimb dysfunction was accompanied by a persistent inflammatory response (demonstrated by CD45(+) immunofluorescence) and axonal loss (demonstrated by NF-M immunofluorescence and electron microscopy; EM). These cellular responses differ from the rat where inflammation resolves by 3-4 weeks and axon loss is minimal following EB demyelination. As these data suggest that EB-injection in the mouse spinal cord is a non-remyelinating lesion, we sought to ask whether wheel running could promote recovery by enhancing plasticity of local lumbar circuitry independent of remyelination. This did not occur as BMS and Treadscan assessment revealed no significant effect of wheel running on recovery. However, this study defines the importance of descending ventral motor pathways to locomotor function in the mouse as VWM loss results in a chronic hindlimb deficit.
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Affiliation(s)
- Nicholas J Kuypers
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY 40292, USA
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Cervical response among ascending ventrolateral funiculus pathways of the neonatal rat. Brain Res 2013; 1491:136-46. [DOI: 10.1016/j.brainres.2012.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Revised: 10/02/2012] [Accepted: 11/04/2012] [Indexed: 12/28/2022]
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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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Magnetic field-based delivery of human CD133⁺ cells promotes functional recovery after rat spinal cord injury. Spine (Phila Pa 1976) 2012; 37:E768-77. [PMID: 22246536 DOI: 10.1097/brs.0b013e318246d59c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Experimental animal study of spinal cord injury (SCI), using a cell delivery system. OBJECTIVE To investigate the therapeutic effects of transplantation of peripheral blood-derived CD133 cells, with a magnetic delivery system in a rat SCI model. SUMMARY OF BACKGROUND DATA There are no reports on intrathecal transplantation of peripheral blood-derived CD133 cells, with a magnetic cell delivery system to treat SCI. METHODS Magnetically isolated peripheral blood-derived CD133 cells were used as the cell source. Contusion SCI was induced by an Infinite Horizon impactor in athymic nude rats. CD133 cells or phosphate-buffered saline was administered via a lumbar puncture immediately after SCI, and a magnetic field was applied to rats for 30 minutes. Animals were analyzed at specific times after transplantation by several methods to examine cell tracking, functional recovery, and histological angiogenesis and neurogenesis. RESULTS A combination of cell transplantation and application of a magnetic field at the site of injury caused significant functional recovery. Transplantation of the cells alone in the absence of the magnetic field showed no effect beyond that observed in control rats. CONCLUSION The combination of intrathecal transplantation of CD133 cells and application of a magnetic field at the site of injury is a possible therapeutic strategy to treat rat SCI and may therefore find application in clinical settings.
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Hunanyan AS, Petrosyan HA, Alessi V, Arvanian VL. Repetitive spinal electromagnetic stimulation opens a window of synaptic plasticity in damaged spinal cord: role of NMDA receptors. J Neurophysiol 2012; 107:3027-39. [PMID: 22402659 DOI: 10.1152/jn.00015.2012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
As we reported previously, propagation of action potentials through surviving axons is impaired dramatically, resulting in reduced transmission to lumbar motoneurons after midthoracic lateral hemisection (HX) in rats. The aim of the present study was to evoke action potentials through the spared fibers using noninvasive electromagnetic stimulation (EMS) over intact T2 vertebrae in an attempt to activate synaptic inputs to lumbar motoneurons and thus to enhance plasticity of spinal neural circuits after HX. We found that EMS was able to activate synaptic inputs to lumbar motoneurons and motor-evoked potentials (MEP) in hindlimb muscles in adult anesthetized rats. Amplitude of MEP was attenuated in parallel with the decline of responses recorded from the motoneuron pool after HX. Repetitive EMS (50 min, 0.2 Hz) facilitated the amplitudes of responses elicited by electric stimulation of lateral white matter or dorsal corticospinal tracts in HX rats. Facilitation sustained for at least 1.5 h after termination of EMS. The N-methyl-d-aspartate (NMDA) receptor blocker MK-801, injected intraspinally close to the recording electrode prior to EMS, did not alter these responses but blocked the EMS-induced facilitation, suggesting that activation of NMDA receptors is required to initiate an EMS-evoked increase. When MK-801 was administered after EMS-induced facilitation was established, it induced depression of these elevated responses. Results suggest that repetitive EMS over intact vertebrae could be used as a therapeutic approach to open a window of synaptic plasticity after incomplete midthoracic injuries, i.e., to activate NMDA receptors in the lumbar motoneuron pool at synaptic inputs and to strengthen transmission in damaged spinal cord.
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Affiliation(s)
- Arsen S Hunanyan
- Northport Veterans Affairs Medical Center, Northport, NY 11768, USA
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Popovich PG, Tovar CA, Wei P, Fisher L, Jakeman LB, Basso DM. A reassessment of a classic neuroprotective combination therapy for spinal cord injured rats: LPS/pregnenolone/indomethacin. Exp Neurol 2012; 233:677-85. [PMID: 22177997 PMCID: PMC3477520 DOI: 10.1016/j.expneurol.2011.11.045] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 11/17/2011] [Accepted: 11/29/2011] [Indexed: 11/20/2022]
Abstract
These experiments were completed as part of an NIH-NINDS contract entitled "Facilities of Research Excellence-Spinal Cord Injury (FORE-SCI)-Replication". Our goal was to replicate data from a paper published by Dr. Lloyd Guth and colleagues in which combined injections of lipopolysaccharide, indomethacin and pregnenolone (referred to herein as LIP therapy) conferred marked neuroprotection in a pre-clinical model of spinal cord injury (SCI). Specifically, post-injury injection of the combination LIP therapy was found to significantly reduce tissue damage at/nearby the site of injury and significantly improve recovery of locomotor function. In this report, we confirm the primary observations made by Guth et al., however, the effects of LIP treatment were modest. Specifically, LIP treatment improved myelin and axon sparing, axonal sprouting while reducing lesion cavitation. However, spontaneous recovery of locomotion, as assessed using historical (Tarlov scoring) and more current rating scales (i.e., BBB scoring), was not affected by LIP treatment. Instead, more refined parameters of functional recovery (paw placement accuracy during grid walk) revealed a significant effect of treatment. Possible explanations for the neuroprotective effects of LIP therapy are described along with reasons why the magnitude of neuroprotection may have differed between this study and that of Guth and colleagues.
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Affiliation(s)
- Phillip G Popovich
- Center for Brain and Spinal Cord Repair, The Ohio State University College of Medicine, Columbus, OH, USA.
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Reier PJ, Lane MA, Hall ED, Teng YD, Howland DR. Translational spinal cord injury research: preclinical guidelines and challenges. HANDBOOK OF CLINICAL NEUROLOGY 2012; 109:411-33. [PMID: 23098728 PMCID: PMC4288927 DOI: 10.1016/b978-0-444-52137-8.00026-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Advances in the neurobiology of spinal cord injury (SCI) have prompted increasing attention to opportunities for moving experimental strategies towards clinical applications. Preclinical studies are the centerpiece of the translational process. A major challenge is to establish strategies for achieving optimal translational progression while minimizing potential repetition of previous disappointments associated with clinical trials. This chapter reviews and expands upon views pertaining to preclinical design reported in recently published opinion surveys. Subsequent discussion addresses other preclinical considerations more specifically related to current and potentially imminent cellular and pharmacological approaches to acute/subacute and chronic SCI. Lastly, a retrospective and prospective analysis examines how guidelines currently under discussion relate to select examples of past, current, and future clinical translations. Although achieving definition of the "perfect" preclinical scenario is difficult to envision, this review identifies therapeutic robustness and independent replication of promising experimental findings as absolutely critical prerequisites for clinical translation. Unfortunately, neither has been fully embraced thus far. Accordingly, this review challenges the notion "everything works in animals and nothing in humans", since more rigor must first be incorporated into the bench-to-bedside translational process by all concerned, whether in academia, clinical medicine, or corporate circles.
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Affiliation(s)
- Paul J Reier
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, USA.
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Kim JH, Song SK, Burke DA, Magnuson DSK. Comprehensive locomotor outcomes correlate to hyperacute diffusion tensor measures after spinal cord injury in the adult rat. Exp Neurol 2011; 235:188-96. [PMID: 22119625 DOI: 10.1016/j.expneurol.2011.11.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 10/10/2011] [Accepted: 11/10/2011] [Indexed: 01/02/2023]
Abstract
In adult rats, locomotor deficits following a contusive thoracic spinal cord injury (SCI) are caused primarily by white matter loss/dysfunction at the epicenter. This loss/dysfunction decreases descending input from the brain and cervical spinal cord, and decreases ascending signals in long propriospinal, spinocerebellar and somatosensory pathways, among many others. Predicting the long-term functional consequences of a contusive injury acutely, without knowledge of the injury severity is difficult due to the temporary flaccid paralysis and loss of reflexes that accompany spinal shock. It is now well known that recovery of high quality hindlimb stepping requires only 12-15% spared white matter at the epicenter, but that forelimb-hindlimb coordination and precision stepping (grid or horizontal ladder) require substantially more trans-contusion communication. In order to translate our understanding of the neural substrates for functional recovery in the rat to the clinical arena, common outcome measures and imaging modalities are required. In the current study we furthered the exploration of one of these approaches, diffusion tensor magnetic resonance imaging (DTI), a technique now used commonly to image the brain in clinical research but rarely used diagnostically or prognostically for spinal cord injury. In the adult rat model of SCI, we found that hyperacute (<3h post-injury) DTI of the lateral and ventral white matter at the injury epicenter was predictive of both electrophysiological and behavioral (locomotor) recovery at 4 weeks post-injury, despite the presence of flaccid paralysis/spinal shock. Regions of white matter with a minimum axial diffusivity of 1.5 μm(2)/ms at 3h were able to conduct action potentials at 4 weeks, and axial diffusivity within the lateral funiculus was highly predictive of locomotor function at 4 weeks. These observations suggest that acute DTI should be useful to provide functional predictions for spared white matter following contusive spinal cord injuries clinically.
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Affiliation(s)
- Joong H Kim
- Department of Radiology, Washington University, St. Louis, MO 63110, USA
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Hwang DH, Kim HM, Kang YM, Joo IS, Cho CS, Yoon BW, Kim SU, Kim BG. Combination of Multifaceted Strategies to Maximize the Therapeutic Benefits of Neural Stem Cell Transplantation for Spinal Cord Repair. Cell Transplant 2011; 20:1361-79. [DOI: 10.3727/096368910x557155] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Neural stem cells (NSCs) possess therapeutic potentials to reverse complex pathological processes following spinal cord injury (SCI), but many obstacles remain that could not be fully overcome by NSC transplantation alone. Combining complementary strategies might be required to advance NSC-based treatments to the clinical stage. The present study was undertaken to examine whether combination of NSCs, polymer scaffolds, neurotrophin-3 (NT3), and chondroitinase, which cleaves chondroitin sulfate proteoglycans at the interface between spinal cord and implanted scaffold, could provide additive therapeutic benefits. In a rat hemisection model, poly(e-caprolactone) (PCL) was used as a bridging scaffold and as a vehicle for NSC delivery. The PCL scaffolds seeded with F3 NSCs or NT3 overexpressing F3 cells (F3.NT3) were implanted into hemisected cavities. F3.NT3 showed better survival and migration, and more frequently differentiated into neurons and oligodendrocytes than F3 cells. Animals with PCL scaffold containing F3.NT3 cells showed the best locomotor recovery, and motor evoked potentials (MEPs) following transcranial magnetic stimulation were recorded only in PCL-F3.NT3 group in contralateral, but not ipsilateral, hindlimbs. Implantation of PCL scaffold with F3.NT3 cells increased NT3 levels, promoted neuroplasticity, and enhanced remyelination of contralateral white matter. Combining chondroitinase treatment after PCL-F3.NT3 implantation further enhanced cell migration and promoted axonal remodeling, and this was accompanied by augmented locomotor recovery and restoration of MEPs in ipsilateral hindlimbs. We demonstrate that combining multifaceted strategies can maximize the therapeutic benefits of NSC transplantation for SCI. Our results may have important clinical implications for the design of future NSC-based strategies.
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Affiliation(s)
- Dong H. Hwang
- Brain Disease Research Center, Institute of Medical Sciences, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Hyuk M. Kim
- Brain Disease Research Center, Institute of Medical Sciences, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Young M. Kang
- Brain Disease Research Center, Institute of Medical Sciences, Ajou University School of Medicine, Suwon, Republic of Korea
| | - In S. Joo
- Department of Neurology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Chong-Su Cho
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
| | - Byung-Woo Yoon
- Departments of Neurology and Neuroscience Research Center, Clinical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Seung U. Kim
- Department of Neurology, University of British Columbia, Vancouver, BC, Canada
- Medical Research Institute, Chungang University School of Medicine, Seoul, Republic of Korea
| | - Byung G. Kim
- Brain Disease Research Center, Institute of Medical Sciences, Ajou University School of Medicine, Suwon, Republic of Korea
- Department of Neurology, Ajou University School of Medicine, Suwon, Republic of Korea
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García-Alías G, Fawcett JW. Training and anti-CSPG combination therapy for spinal cord injury. Exp Neurol 2011; 235:26-32. [PMID: 21946272 DOI: 10.1016/j.expneurol.2011.09.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 08/23/2011] [Accepted: 09/09/2011] [Indexed: 12/18/2022]
Abstract
Combining different therapies is a promising strategy to promote spinal cord repair, by targeting axon plasticity and functional circuit reconnectivity. In particular, digestion of chondroitin sulphate proteoglycans at the site of the injury by the activity of the bacterial enzyme chondrotinase ABC, together with the development of intensive task specific motor rehabilitation has shown synergistic effects to promote behavioural recovery. This review describes the mechanisms by which chondroitinase ABC and motor rehabilitation promote neural plasticity and we discuss their additive and independent effects on promoting behavioural recovery.
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Initiation of segmental locomotor-like activities by stimulation of ventrolateral funiculus in the neonatal rat. Exp Brain Res 2011; 214:151-61. [PMID: 21858680 DOI: 10.1007/s00221-011-2816-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 07/23/2011] [Indexed: 10/17/2022]
Abstract
Descending control is critically important for the generation of locomotor activities. Yet, our understanding of the descending control system of locomotion is limited. We hypothesized that stimulation of the ventrolateral funiculus (VLF) induces rhythmic activity in lumbar neurons that is correlated with locomotor-like activity in the neonatal rat. Intracellular recordings were conducted in the L2-L3 lumbar segments, while locomotor-like output was monitored in the L2 and L5 ventral roots. Stimulation of the VLF at thoracic segments induced locomotor-like activity in the L2 and L5 ventral roots in majority of the preparations (26/33). In a few midline split cord preparations (4/13), VLF stimulation induced rhythmic locomotor-like bursts in either L2 or L5 ventral root without alternating pattern between the ventral roots. The response latencies suggest that VLF stimulation induced antidromic activation (<1 ms, 8 cells), monosynaptic activation (1-3 ms, 18 cells), and oligosynaptic activation (3.5-5 ms, 14 cells) of segmental neurons in the lumbar region. VLF stimulation induced rhythmic membrane potential oscillations with or without bursting of action potentials in 9 of 40 putative interneurons. The membrane potential oscillations were in phase with the locomotor-like output of the L2 ventral root in 7 of the 9 cells while the other 2 cells oscillated in phase with the L5 ventral root activity. We have thus demonstrated that descending axons exist in the VLF which make synaptic connections with segmental neurons in the lumbar region that may be a critical element of the locomotor neural network for the initiation of locomotion.
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Iannotti CA, Clark M, Horn KP, van Rooijen N, Silver J, Steinmetz MP. A combination immunomodulatory treatment promotes neuroprotection and locomotor recovery after contusion SCI. Exp Neurol 2011; 230:3-15. [DOI: 10.1016/j.expneurol.2010.03.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2009] [Revised: 03/04/2010] [Accepted: 03/10/2010] [Indexed: 10/19/2022]
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Onifer SM, Smith GM, Fouad K. Plasticity after spinal cord injury: relevance to recovery and approaches to facilitate it. Neurotherapeutics 2011; 8:283-93. [PMID: 21384221 PMCID: PMC3101826 DOI: 10.1007/s13311-011-0034-4] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Motor, sensory, and autonomic functions can spontaneously return or recover to varying extents in both humans and animals, regardless of the traumatic spinal cord injury (SCI) level and whether it was complete or incomplete. In parallel, adverse and painful functions can appear. The underlying mechanisms for all of these diverse functional changes are summarized under the term plasticity. Our review will describe what is known regarding this phenomenon after traumatic SCI and focus on its relevance to motor and sensory recovery. Although it is still somewhat speculative, plasticity can be found throughout the neuraxis and includes various changes ranging from alterations in the properties of spared neuronal circuitries, intact or lesioned axon collateral sprouting, and synaptic rearrangements. Furthermore, we will discuss a selection of potential approaches for facilitating plasticity as possible SCI treatments. Because a mechanism underlying spontaneous plasticity and recovery might be motor activity and the related neuronal activity, activity-based therapies are being used and investigated both clinically and experimentally. Additional pharmacological and gene-delivery approaches, based on plasticity being dependent on the delicate balance between growth inhibition and promotion as well as the basic intrinsic growth ability of the neurons themselves, have been found to be effective alone and in combination with activity-based therapies. The positive results have to be tempered with the reality that not all plasticity is beneficial. Therefore, a tremendous number of questions still need to be addressed. Ultimately, answers to these questions will enhance plasticity's potential for improving the quality of life for persons with SCI.
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Affiliation(s)
- Stephen M. Onifer
- Spinal Cord and Brain Injury Research Center, University of Kentucky, College of Medicine, Lexington, Kentucky 40536-0509 USA
- Department of Anatomy and Neurobiology, University of Kentucky, College of Medicine, Lexington, Kentucky 40536-0098 USA
| | - George M. Smith
- Spinal Cord and Brain Injury Research Center, University of Kentucky, College of Medicine, Lexington, Kentucky 40536-0509 USA
- Department of Physiology, University of Kentucky, College of Medicine, Lexington, Kentucky 40536-0298 USA
| | - Karim Fouad
- Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, T6G 2G4 Canada
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Onifer SM, Zhang O, Whitnel-Smith LK, Raza K, O'Dell CR, Lyttle TS, Rabchevsky AG, Kitzman PH, Burke DA. Horizontal ladder task-specific re-training in adult rats with contusive thoracic spinal cord injury. Restor Neurol Neurosci 2011; 29:275-86. [PMID: 21697591 PMCID: PMC3544551 DOI: 10.3233/rnn-2011-598] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE Using the horizontal ladder task, we examined some issues that need to be resolved before task-specific rehabilitative training can be employed clinically for the frequent contusive spinal cord injury (SCI). We hypothesized that improving recovery in task performance after contusive thoracic SCI requires frequent re-training and initiating the re-training early during spontaneous recovery. METHODS Contusive SCI was produced at the adult female Sprague Dawley rat T10 vertebra. Task re-training was initiated one week later when occasional weight-supported plantar steps were taken overground (n = 8). It consisted of 2 repetitions each day, 5 days each week, for 3 weeks. Task performance and overground locomotion were assessed weekly. Neurotransmission through the SCI ventrolateral funiculus was examined. SCI morphometry was determined. RESULTS Re-training did not improve task performance recovery compared to untrained Controls (n = 7). Untrained overground locomotion and neurotransmission through the SCI did not change. Lesion area at the injury epicenter as a percentage of the total spinal cord area as well as total tissue, lesion, and spared tissue, white matter, or gray matter volumes did not differ. CONCLUSIONS For the horizontal ladder task after contusive thoracic SCI, earlier re-training sessions with more repetitions and critical neural circuitry may be necessary to engender a rehabilitation effect.
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Affiliation(s)
- Stephen M Onifer
- Spinal Cord and Brain Injury Research Center, College of Medicine, University of Kentucky, Lexington, KY 40536, USA.
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Post-mortem assessment of rat spinal cord injury and white matter sparing using inversion recovery-supported proton density magnetic resonance imaging. Spinal Cord 2010; 49:345-51. [PMID: 20877332 DOI: 10.1038/sc.2010.129] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
STUDY DESIGN This was an experimental study. OBJECTIVES White matter sparing influences locomotor recovery after traumatic spinal cord injury (SCI). The objective of the present post-mortem magnetic resonance imaging (MRI) investigation was to assess the potential of a simple inversion recovery (IR) sequence in combination with high-resolution proton density (PD) images to selectively depict spared white matter after experimental SCI in the rat. SETTING This study was conducted at University of Liège and Centre Hospitalier Universitaire, Liège, Belgium and Hasselt University, Diepenbeek, Belgium. METHODS Post-mortem 9.4 tesla (T) MRI was obtained from five excised rat spines 2 months after compressive SCI. The locomotor recovery had been followed weekly using the standardized Basso-Beattie-Bresnahan scale. IR MRI was used to depict normal white matter as very hypo-intense. Preserved white matter, cord atrophy and lesion volume were assessed, and histology was used to confirm MRI data. RESULTS MRI showed lesion severity and white matter sparing in accordance with the degree of locomotor recovery. IR MRI enhanced detection of spared and injured white matter by selectively altering the signal of spared white matter. Even subtle white matter changes could be detected, increasing diagnostic accuracy as compared to PD alone. MRI accuracy was confirmed by histology. CONCLUSION High-resolution IR-supported PD MRI provides useful micro-anatomical information about white matter damage and sparing in the post-mortem assessment of chronic rat SCI.
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Shaw AC, Jackson AW, Holmes T, Thurman S, Davis GR, McClellan AD. Descending brain neurons in larval lamprey: spinal projection patterns and initiation of locomotion. Exp Neurol 2010; 224:527-41. [PMID: 20510243 DOI: 10.1016/j.expneurol.2010.05.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 05/18/2010] [Accepted: 05/20/2010] [Indexed: 01/14/2023]
Abstract
In larval lamprey, partial lesions were made in the rostral spinal cord to determine which spinal tracts are important for descending activation of locomotion and to identify descending brain neurons that project in these tracts. In whole animals and in vitro brain/spinal cord preparations, brain-initiated spinal locomotor activity was present when the lateral or intermediate spinal tracts were spared but usually was abolished when the medial tracts were spared. We previously showed that descending brain neurons are located in eleven cell groups, including reticulospinal (RS) neurons in the mesenecephalic reticular nucleus (MRN) as well as the anterior (ARRN), middle (MRRN), and posterior (PRRN) rhombencephalic reticular nuclei. Other descending brain neurons are located in the diencephalic (Di) as well as the anterolateral (ALV), dorsolateral (DLV), and posterolateral (PLV) vagal groups. In the present study, the Mauthner and auxillary Mauthner cells, most neurons in the Di, ALV, DLV, and PLV cell groups, and some neurons in the ARRN and PRRN had crossed descending axons. The majority of neurons projecting in medial spinal tracts included large identified Müller cells and neurons in the Di, MRN, ALV, and DLV. Axons of individual descending brain neurons usually did not switch spinal tracts, have branches in multiple tracts, or cross the midline within the rostral cord. Most neurons that projected in the lateral/intermediate spinal tracts were in the ARRN, MRRN, and PRRN. Thus, output neurons of the locomotor command system are distributed in several reticular nuclei, whose neurons project in relatively wide areas of the cord.
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Affiliation(s)
- Albert C Shaw
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211-6190, USA
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Fouad K, Krajacic A, Tetzlaff W. Spinal cord injury and plasticity: opportunities and challenges. Brain Res Bull 2010; 84:337-42. [PMID: 20471456 DOI: 10.1016/j.brainresbull.2010.04.017] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Revised: 04/29/2010] [Accepted: 04/30/2010] [Indexed: 01/03/2023]
Abstract
There is still no effective treatment to promote functional recovery following spinal cord injury. However, promoting injury-induced adaptive changes (plasticity) within the central nervous system, associated with repair, promise new treatment strategies. Recent contributions from our group and current challenges of this relatively young field are discussed in this review.
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