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Xie J, Herr S, Ma D, Wu S, Zhao H, Sun S, Ma Z, Chan MYL, Li K, Yang Y, Huang F, Shi R, Yuan C. Acute Transcriptomic and Epigenetic Alterations at T12 After Rat T10 Spinal Cord Contusive Injury. Mol Neurobiol 2023; 60:2937-2953. [PMID: 36750527 DOI: 10.1007/s12035-023-03250-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 01/19/2023] [Indexed: 02/09/2023]
Abstract
Spinal cord injury is a severely debilitating condition affecting a significant population in the USA. Spinal cord injury patients often have increased risk of developing persistent neuropathic pain and other neurodegenerative conditions beyond the primary lesion center later in their life. The molecular mechanism conferring to the "latent" damages at distal tissues, however, remains elusive. Here, we studied molecular changes conferring abnormal functionality at distal spinal cord (T12) beyond the lesion center (T10) by combining next-generation sequencing (RNA- and bisulfite sequencing), super-resolution microscopy, and immunofluorescence staining at 7 days post injury. We observed significant transcriptomic changes primarily enriched in neuroinflammation and synaptogenesis associated pathways. Transcription factors (TFs) that regulate neurogenesis and neuron plasticity, including Egr1, Klf4, and Myc, are significantly upregulated. Along with global changes in chromatin arrangements and DNA methylation, including 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC), bisulfite sequencing further reveals the involvement of DNA methylation changes in regulating cytokine, growth factor, and ion channel expression. Collectively, our results pave the way towards understanding transcriptomic and epigenomic mechanism in conferring long-term disease risks at distal tissues away from the primary lesion center and shed light on potential molecular targets that govern the regulatory mechanism at distal spinal cord tissues.
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Affiliation(s)
- Junkai Xie
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, USA
| | - Seth Herr
- Center for Paralysis Research, Purdue University, West Lafayette, IN, USA
- Department of Basic Medical Sciences, Purdue University, West Lafayette, IN, USA
| | - Donghan Ma
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, USA
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Shichen Wu
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, USA
| | - Han Zhao
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, USA
| | - Siyuan Sun
- Center for Paralysis Research, Purdue University, West Lafayette, IN, USA
- Department of Basic Medical Sciences, Purdue University, West Lafayette, IN, USA
| | - Zhixiong Ma
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, USA
| | - Matthew Yan-Lok Chan
- Agriculture and Biological Engineering, Purdue University, West Lafayette, IN, USA
| | - Katherine Li
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, USA
| | - Yang Yang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Fang Huang
- Agriculture and Biological Engineering, Purdue University, West Lafayette, IN, USA
| | - Riyi Shi
- Center for Paralysis Research, Purdue University, West Lafayette, IN, USA.
- Department of Basic Medical Sciences, Purdue University, West Lafayette, IN, USA.
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA.
| | - Chongli Yuan
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, USA.
- Purdue Center of Cancer Research, Purdue University, West Lafayette, IN, USA.
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Bouali-Benazzouz R, Landry M, Benazzouz A, Fossat P. Neuropathic pain modeling: Focus on synaptic and ion channel mechanisms. Prog Neurobiol 2021; 201:102030. [PMID: 33711402 DOI: 10.1016/j.pneurobio.2021.102030] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 02/22/2021] [Indexed: 12/28/2022]
Abstract
Animal models of pain consist of modeling a pain-like state and measuring the consequent behavior. The first animal models of neuropathic pain (NP) were developed in rodents with a total lesion of the sciatic nerve. Later, other models targeting central or peripheral branches of nerves were developed to identify novel mechanisms that contribute to persistent pain conditions in NP. Objective assessment of pain in these different animal models represents a significant challenge for pre-clinical research. Multiple behavioral approaches are used to investigate and to validate pain phenotypes including withdrawal reflex to evoked stimuli, vocalizations, spontaneous pain, but also emotional and affective behaviors. Furthermore, animal models were very useful in investigating the mechanisms of NP. This review will focus on a detailed description of rodent models of NP and provide an overview of the assessment of the sensory and emotional components of pain. A detailed inventory will be made to examine spinal mechanisms involved in NP-induced hyperexcitability and underlying the current pharmacological approaches used in clinics with the possibility to present new avenues for future treatment. The success of pre-clinical studies in this area of research depends on the choice of the relevant model and the appropriate test based on the objectives of the study.
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Affiliation(s)
- Rabia Bouali-Benazzouz
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France.
| | - Marc Landry
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France
| | - Abdelhamid Benazzouz
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France
| | - Pascal Fossat
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France
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Wiedmann NM, Wong AW, Keast JR, Osborne PB. Sex differences in c-Fos and EGR-1/Zif268 activity maps of rat sacral spinal cord following cystometry-induced micturition. J Comp Neurol 2020; 529:311-326. [PMID: 32415681 PMCID: PMC7818477 DOI: 10.1002/cne.24949] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 04/21/2020] [Accepted: 05/07/2020] [Indexed: 12/24/2022]
Abstract
Storage and voiding of urine from the lower urinary tract (LUT) must be timed precisely to occur in appropriate behavioral contexts. A major part of the CNS circuit that coordinates this activity is found in the lumbosacral spinal cord. Immediate early gene (IEG) activity mapping has been widely used to investigate the lumbosacral LUT-related circuit, but most reports focus on the effects of noxious stimulation in anesthetized female rats. Here we use c-Fos and EGR-1 (Zif268) activity mapping of lumbosacral spinal cord to investigate cystometry-induced micturition in awake female and male rats. In females, after cystometry c-Fos neurons in spinal cord segments L5-S2 were concentrated in the sacral parasympathetic nucleus (SPN), dorsal horn laminae II-IV, and dorsal commissural nucleus (SDCom). Comparisons of cystometry and control groups in male and female revealed sex differences. Activity mapping suggested dorsal horn laminae II-IV was activated in females but showed net inhibition in males. However, inhibition in male rats was not detected by EGR-1 activity mapping, which showed low coexpression with c-Fos. A class of catecholamine neurons in SPN and SDCom neurons were also more strongly activated by micturition in females. In both sexes, most c-Fos neurons were identified as excitatory by their absence of Pax2 expression. In conclusion, IEG mapping in awake male and female rats has extended our understanding of the functional molecular anatomy of the LUT-related circuit in spinal cord. Using this approach, we have identified sex differences that were not detected by previous studies in anesthetized rats.
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Affiliation(s)
- Nicole M Wiedmann
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Agnes W Wong
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Janet R Keast
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Peregrine B Osborne
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
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Yasko JR, Moss IL, Mains RE. Transcriptional Profiling of Non-injured Nociceptors After Spinal Cord Injury Reveals Diverse Molecular Changes. Front Mol Neurosci 2019; 12:284. [PMID: 32038157 PMCID: PMC6988781 DOI: 10.3389/fnmol.2019.00284] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 11/08/2019] [Indexed: 01/01/2023] Open
Abstract
Traumatic spinal cord injury (SCI) has devastating implications for patients, including a high predisposition for developing chronic pain distal to the site of injury. Chronic pain develops weeks to months after injury, consequently, patients are treated after irreparable changes have occurred. Nociceptors are central to chronic pain; however, the diversity of this cellular population presents challenges to understanding mechanisms and attributing pain modalities to specific cell types. To begin to address how peripheral sensory neurons below the injury level may contribute to the below-level pain reported by SCI patients, we examined SCI-induced changes in gene expression in lumbar dorsal root ganglia (DRG) below the site of injury. SCI was performed at the T10 vertebral level, with injury produced by a vessel clip with a closing pressure of 15 g for 1 min. Alterations in gene expression produce long-term sensory changes, therefore, we were interested in studying SCI-induced transcripts before the onset of chronic pain, which may trigger changes in downstream signaling pathways and ultimately facilitate the transmission of pain. To examine changes in the nociceptor subpopulation in DRG distal to the site of injury, we retrograde labeled sensory neurons projecting to the hairy hindpaw skin with fluorescent dye and collected the corresponding lumbar (L2–L6) DRG 4 days post-injury. Following dissociation, labeled neurons were purified by fluorescence-activated cell sorting (FACS). RNA was extracted from sorted sensory neurons of naïve, sham, or SCI mice and sequenced. Transcript abundances validated that the desired population of nociceptors were isolated. Cross-comparisons to data sets from similar studies confirmed, we were able to isolate our cells of interest and identify a unique pattern of gene expression within a subpopulation of neurons projecting to the hairy hindpaw skin. Differential gene expression analysis showed high expression levels and significant transcript changes 4 days post-injury in SCI cell populations relevant to the onset of chronic pain. Regulatory interrelationships predicted by pathway analysis implicated changes within the synaptogenesis signaling pathway as well as networks related to inflammatory signaling mechanisms, suggesting a role for synaptic plasticity and a correlation with pro-inflammatory signaling in the transition from acute to chronic pain.
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Affiliation(s)
- Jessica R Yasko
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, United States
| | - Isaac L Moss
- Department of Orthopedic Surgery and the Comprehensive Spine Center, University of Connecticut Health Center, Farmington, CT, United States
| | - Richard E Mains
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, United States
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Duan W, Huang Q, Chen Z, Raja SN, Yang F, Guan Y. Comparisons of motor and sensory abnormalities after lumbar and thoracic contusion spinal cord injury in male rats. Neurosci Lett 2019; 708:134358. [PMID: 31269465 DOI: 10.1016/j.neulet.2019.134358] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 06/25/2019] [Accepted: 06/28/2019] [Indexed: 12/23/2022]
Abstract
Rodent models of contusion spinal cord injury (SCI) are widely studied for the mechanisms underlying functional deficits after SCI. Yet, how does lesion level affect SCI-induced motor and sensory dysfunctions remains unclear. Using a computer-controlled impactor (Impact One™, Leica) and the same parameters (diameter, 2.0 mm; Speed: 4.0 m/s; Depth: 1.5 mm; Dwell time: 0.1 s), we produced contusions at mid-thoracic (T10) and rostral-lumbar (L2) spinal cord in male rats, and compared locomotor and sensory dysfunctions within the same experimental setting. The time courses of locomotor deficit were comparable between thoracic (n = 8) and lumbar (n = 7) SCI rats, but the severity was greater after thoracic SCI especially during the first week post-injury, as indicated by the lower Basso, Beattle and Bresnahan open-field locomotion scores. Both groups showed similar heightened avoiding response (hyper-reactivity) to mechanical stimulation applied at the hindpaws from day 21-56 post-injury, as indicated by decreased paw withdrawal thresholds. Compared to lumbar SCI, thoracic SCI induced a greater decrease of paw withdrawal latency in hot-plate test from day 28-56 post-injury. In contrast, lumbar SCI rats showed a greater reduction of avoidance threshold to mechanical stimulation at the girdle region, and larger overgroomed area than thoracic SCI rats at day 14 post-injury. Thus, thoracic SCI may induce greater motor deficits and hindpaw heat hyper-reactivity than did lumbar SCI. In contrast, lumbar SCI may elicit greater at-level mechanical hyper-reactivity and overgrooming behavior than thoracic SCI. Future study needs to examine the specific pathological changes underlying different dysfunctions in two SCI models.
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Affiliation(s)
- Wanru Duan
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, 100053, China; Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Qian Huang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Zhiyong Chen
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Srinivasa N Raja
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Fei Yang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA; Department of Neurobiology, School of Basic Medical Sciences, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, 100069, China
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA; Department of Neurological Surgery, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA.
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Matsubayashi K, Nagoshi N, Komaki Y, Kojima K, Shinozaki M, Tsuji O, Iwanami A, Ishihara R, Takata N, Matsumoto M, Mimura M, Okano H, Nakamura M. Assessing cortical plasticity after spinal cord injury by using resting-state functional magnetic resonance imaging in awake adult mice. Sci Rep 2018; 8:14406. [PMID: 30258091 PMCID: PMC6158265 DOI: 10.1038/s41598-018-32766-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 07/26/2018] [Indexed: 12/30/2022] Open
Abstract
Neural connectivity has recently been shown to be altered after spinal cord injury (SCI) not only in the spinal cord but also in the brain. However, to date, no studies have analyzed the functional alterations after SCI in various areas of the cerebral cortex over time. To examine the plasticity of the neural connectivity in the brain after SCI, we performed resting-state functional magnetic resonance imaging (rs-fMRI) in awake adult mice pre- and post-SCI. After a complete thoracic SCI, the functional connectivity between the primary motor (MOp) and primary sensory (SSp) areas was significantly decreased during the chronic phase. In contrast, the connectivity between the MOp and motivation area was increased. Thus, impairments in sensory and motor connections after SCI led to a time-dependent compensatory upregulation of “motor functional motivation”. Moreover, the functional connectivity between the SSp and pain-related areas, such as the caudoputamen (CP) and the anterior cingulate area (ACA), was strengthened during the chronic phase, thus suggesting that rs-fMRI can indicate the presence of neuropathic pain after SCI. Therefore, rs-fMRI is a useful tool for revealing the pathological changes that occur in the brain after SCI.
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Affiliation(s)
- Kohei Matsubayashi
- Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan.,Department of Physiology, Keio University School of Medicine, Tokyo, Japan
| | - Narihito Nagoshi
- Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan
| | - Yuji Komaki
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan.,Central Institute for Experimental Animals, Kawasaki, Japan
| | - Kota Kojima
- Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan
| | - Munehisa Shinozaki
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
| | - Osahiko Tsuji
- Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan
| | - Akio Iwanami
- Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan
| | - Ryosuke Ishihara
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Norio Takata
- Central Institute for Experimental Animals, Kawasaki, Japan.,Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Morio Matsumoto
- Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan
| | - Masaru Mimura
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan. .,Laboratory for Marmoset Neural Architecture, RIKEN Center for Brain Science, Wako-shi, Saitama, 351-0198, Japan.
| | - Masaya Nakamura
- Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan.
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Shiao R, Lee-Kubli CA. Neuropathic Pain After Spinal Cord Injury: Challenges and Research Perspectives. Neurotherapeutics 2018; 15:635-653. [PMID: 29736857 PMCID: PMC6095789 DOI: 10.1007/s13311-018-0633-4] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Neuropathic pain is a debilitating consequence of spinal cord injury (SCI) that remains difficult to treat because underlying mechanisms are not yet fully understood. In part, this is due to limitations of evaluating neuropathic pain in animal models in general, and SCI rodents in particular. Though pain in patients is primarily spontaneous, with relatively few patients experiencing evoked pains, animal models of SCI pain have primarily relied upon evoked withdrawals. Greater use of operant tasks for evaluation of the affective dimension of pain in rodents is needed, but these tests have their own limitations such that additional studies of the relationship between evoked withdrawals and operant outcomes are recommended. In preclinical SCI models, enhanced reflex withdrawal or pain responses can arise from pathological changes that occur at any point along the sensory neuraxis. Use of quantitative sensory testing for identification of optimal treatment approach may yield improved identification of treatment options and clinical trial design. Additionally, a better understanding of the differences between mechanisms contributing to at- versus below-level neuropathic pain and neuropathic pain versus spasticity may shed insights into novel treatment options. Finally, the role of patient characteristics such as age and sex in pathogenesis of neuropathic SCI pain remains to be addressed.
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Affiliation(s)
- Rani Shiao
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 N. Torrey Pines, La Jolla, California, 92073, USA
| | - Corinne A Lee-Kubli
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 N. Torrey Pines, La Jolla, California, 92073, USA.
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The Neurotoxin DSP-4 Induces Hyperalgesia in Rats that is Accompanied by Spinal Oxidative Stress and Cytokine Production. Neuroscience 2018; 376:13-23. [PMID: 29421433 DOI: 10.1016/j.neuroscience.2018.01.058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 01/26/2018] [Accepted: 01/29/2018] [Indexed: 12/30/2022]
Abstract
Central neuropathic pain (CNP) a significant problem for many people, is not well-understood and difficult to manage. Dysfunction of the central noradrenergic system originating in the locus coeruleus (LC) may be a causative factor in the development of CNP. The LC is the major noradrenergic nucleus of the brain and plays a significant role in central modulation of nociceptive neurotransmission. Here, we examined CNS pathophysiological changes induced by intraperitoneal administration of the neurotoxin DSP-4 (N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride). Administration of DSP-4 decreased levels of norepinephrine in spinal tissue and cerebrospinal fluid (CSF) and led to the development of thermal and mechanical hyperalgesia over 21 days, that was reversible with morphine. Hyperalgesia was accompanied by significant increases in noradrenochrome (oxidized norepinephrine) and expression of 4-hydroxynonenal in CSF and spinal cord tissue respectively at day 21, indicative of oxidative stress. In addition, spinal levels of pro-inflammatory cytokines (interleukins 6 and 17A, tumor necrosis factor-α), as well as the anti-inflammatory cytokine interleukin10 were also significantly elevated at day 21, indicating that an inflammatory response occurred. The inflammatory effect of DSP-4 presented in this study that includes oxidative stress may be particularly useful in elucidating mechanisms of CNP in inflammatory disease states.
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Song RB, Basso DM, da Costa RC, Fisher LC, Mo X, Moore SA. von Frey anesthesiometry to assess sensory impairment after acute spinal cord injury caused by thoracolumbar intervertebral disc extrusion in dogs. Vet J 2016; 209:144-9. [PMID: 26832808 PMCID: PMC4749468 DOI: 10.1016/j.tvjl.2015.07.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 07/06/2015] [Accepted: 07/26/2015] [Indexed: 01/17/2023]
Abstract
Sensory threshold (ST) was measured using an electric von Frey anesthesiometer (VFA) in all limbs of 20 normal dogs and 29 dogs with acute thoracolumbar spinal cord injury (SCI) caused by spontaneous intervertebral disc extrusion. ST values were measured at three separate time points in normal dogs and on days 3, 10 and 30 following decompressive surgery in dogs with SCI. ST values were compared between groups and correlated with locomotor recovery in SCI-affected dogs. ST values were significantly higher (consistent with hypoalgesia) in the pelvic limbs of SCI-affected dogs at day 3, day 10 and day 30 when compared to normal dogs (P <0.05), while no significant difference in thoracic limb ST values was observed between groups. A progressive decrease in pelvic limb ST values occurred in SCI-affected dogs over time, consistent with improvement toward normal sensation or development of allodynia. This finding correlated inversely with locomotor score at 3 and 10 days after surgery. A significant decline in ST values across testing sessions was observed for all limbs of normal and SCI-affected dogs and may be related to patient acclimation, operator training effect, or effect of analgesic medications. This study supports the feasibility of VFA to assess differences in ST between normal and SCI-affected dogs. However, future studies must focus on techniques to minimize or compensate for clinical, environmental and behavioral factors which may impact ST values in the clinical setting.
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Affiliation(s)
- R B Song
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, 601 Vernon TharP St., Columbus, OH 43210, USA
| | - D M Basso
- School of Health and Rehabilitation Sciences, The Ohio State University, 453 West Tenth Ave, Columbus, OH 43210, USA
| | - R C da Costa
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, 601 Vernon TharP St., Columbus, OH 43210, USA
| | - L C Fisher
- School of Health and Rehabilitation Sciences, The Ohio State University, 453 West Tenth Ave, Columbus, OH 43210, USA
| | - X Mo
- Center for Biostatistics, The Ohio State University, 601 Vernon TharP St., Columbus, OH 43210, USA
| | - S A Moore
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, 601 Vernon TharP St., Columbus, OH 43210, USA.
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Analysis of the behavioral, cellular and molecular characteristics of pain in severe rodent spinal cord injury. Exp Neurol 2016; 278:91-104. [PMID: 26808661 DOI: 10.1016/j.expneurol.2016.01.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 01/07/2016] [Accepted: 01/12/2016] [Indexed: 12/31/2022]
Abstract
Human SCI is frequently associated with chronic pain that is severe and refractory to medical therapy. Most rodent models used to assess pain outcomes in SCI apply moderate injuries to lower thoracic spinal levels, whereas the majority of human lesions are severe in degree and occur at cervical or upper thoracic levels. To better model and understand mechanisms associated with chronic pain after SCI, we subjected adult rats to T3 severe compression or complete transection lesions, and examined pain-related behaviors for three months. Within one week after injury, rats developed consistent forepaw pain-related behaviors including increased spontaneous lifts, tactile allodynia and cold sensitivity that persisted for three months. Place escape avoidance testing confirmed that withdrawal of the forepaws from a von Frey stimulus represented active pain-related aversion. Spontaneous and evoked pain-related measures were attenuated by gabapentin, further indicating that these behaviors reflect development of pain. Spinal level of injury was relevant: rats with T11 severe SCI did not exhibit forepaw pain-related behaviors. Immunoblotting and immunofluorescence of C6-C8 spinal dorsal horn, reflecting sensory innervation of the forepaw, revealed: 1) expansion of CGRP immunoreactivity in lamina I/II; 2) increased GAP-43 expression; and 3) increased IBA1, GFAP and connexin-43 expression. These findings indicate that aberrant pain fiber sprouting and gliopathy occur after severe SCI. Notably, satellite glial cells (SGCs) in C6-C8 DRGs exhibited increases in GFAP and connexin-43, suggesting ongoing peripheral sensitization. Carbenoxolone, a gap junction inhibitor, and specific peptide inhibitors of connexin-43, ameliorated established tactile allodynia after severe SCI. Collectively, severe T3 SCI successfully models persistent pain states and could constitute a useful model system for examining candidate translational pain therapies after SCI.
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11
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Bojovic O, Bramham CR, Tjølsen A. Stimulation-induced expression of immediate early gene proteins in the dorsal horn is increased in neuropathy. Scand J Pain 2016; 10:43-51. [PMID: 28361770 DOI: 10.1016/j.sjpain.2015.09.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 09/05/2015] [Accepted: 09/08/2015] [Indexed: 12/27/2022]
Abstract
BACKGROUND AND AIMS Peripheral neuropathic pain is described as a pain state caused by an injury or dysfunction of the nervous system, and could have clinical manifestations such as hyperalgesia, allodynia and spontaneous pain. The development of neuropathic pain may depend on long-term forms of neuronal plasticity in the spinal cord (SC). Expression of the immediate early gene proteins (IEGPs) Arc, Zif268, and c-Fos are implicated in establishment of long-term potentiation (LTP) induced by conditioning stimulation (CS) of primary afferent fibres. However, the impact of the neuropathic state (Bennett's model) on CS-induced expression of IEGPs has not been studied. The aim of this study was to compare the levels of Arc, c-Fos and Zif268 immunoreactivity prior to and after conditioning stimulation in animals with developed neuropathic pain, with sham operated, non-ligated controls. METHODS Twenty-four animals were divided equally into the neuropathic and non-neuropathic groups. Neuropathic pain was induced in all animals by conducting a loose ligation of the sciatic nerve with Chromic Catgut 4.0 sutures 7 days prior to conditioning stimulation or sham operation. The loose ligation was performed by placing sutures around the sciatic nerve compressing the nerve slightly just enough to reduce but not completely diminish the perineural circulation. A state of neuropathy was confirmed by a significant decrease in mechanical withdrawal threshold measured by von Frey's fibres. Immunohistochemical analysis was performed on transverse sections obtained from the L3-L5 segments of the SC at 2 and 6h post-CS and IEGP positive cells were counted in lamina I and II of the dorsal horn. During statistical analyses, the groups were compared by means of analysis of variance (univariate general linear model). If significant differences were found, each set of animals was compared with the sham group with post hoc Tukey's multiple comparison test. RESULTS Strikingly, all IEGPs exhibited a significant increase in immunoreactivity at both time points compared to time-matched, sham operated controls. Maximal IEGP expression was found 2h after CS in neuropathic rats, and there was a smaller but still significant increase 6h after CS. The unstimulated side of the dorsal horn in stimulated animals did not show any significant change of the number of IEGP positive cells and was approximately at the same level as sham operated animals. The number of IEGP positive cells in sham operated controls (non-neuropathic and non-stimulated animals) showed same immunoreactivity in 2 and 6h post sham operation. CONCLUSIONS AND IMPLICATIONS The neurophysiological process of neuropathic pain development is complex and needs to be studied further in order to clarify its nature and components. This present study is meant to reveal a step towards further understanding the role of Arc, c-Fos and Zif268 in neuropathic pain. Moreover, this study might contribute to the knowledge base for further research on better therapeutic possibilities for neuropathic pain.
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Affiliation(s)
- Ognjen Bojovic
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5009Bergen, Norway
| | - Clive R Bramham
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5009Bergen, Norway
| | - Arne Tjølsen
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5009Bergen, Norway
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12
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Khan N, Woodruff TM, Smith MT. Establishment and characterization of an optimized mouse model of multiple sclerosis-induced neuropathic pain using behavioral, pharmacologic, histologic and immunohistochemical methods. Pharmacol Biochem Behav 2014; 126:13-27. [PMID: 25223977 DOI: 10.1016/j.pbb.2014.09.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/25/2014] [Accepted: 09/06/2014] [Indexed: 11/19/2022]
Abstract
Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS) that causes debilitating central neuropathic pain in many patients. Although mouse models of experimental autoimmune encephalomyelitis (EAE) have provided insight on the pathobiology of MS-induced neuropathic pain, concurrent severe motor impairments confound quantitative assessment of pain behaviors over the disease course. To address this issue, we have established and characterized an optimized EAE-mouse model of MS-induced neuropathic pain. Briefly, C57BL/6 mice were immunized with MOG35-55 (200μg) and adjuvants comprising Quil A (45μg) and pertussis toxin (2×250ng). The traditionally used Freund's Complete Adjuvant (FCA) was replaced with Quil A, as FCA itself induces CNS neuroinflammation. Herein, EAE-mice exhibited a mild relapsing-remitting clinical disease course with temporal development of mechanical allodynia in the bilateral hindpaws. Mechanical allodynia was fully developed by 28-30days post-immunization (p.i.) and was maintained until study completion (52-60days p.i.), in the absence of confounding motor deficits. Single bolus doses of amitriptyline (1-7mg/kg), gabapentin (10-50mg/kg) and morphine (0.1-2mg/kg) evoked dose-dependent analgesia in the bilateral hindpaws of EAE-mice; the corresponding ED50s were 1.5, 20 and 1mg/kg respectively. At day 39 p.i. in EAE-mice exhibiting mechanical allodynia in the hindpaws, there was marked demyelination and gliosis in the brain and lumbar spinal cord, mirroring these pathobiologic hallmark features of MS in humans. Our optimized EAE-mouse model of MS-associated neuropathic pain will be invaluable for future investigation of the pathobiology of MS-induced neuropathic pain and for efficacy profiling of novel molecules as potential new analgesics for improved relief of this condition.
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MESH Headings
- Amines/therapeutic use
- Amitriptyline/therapeutic use
- Animals
- Anti-Inflammatory Agents, Non-Steroidal/therapeutic use
- Brain/pathology
- Cyclohexanecarboxylic Acids/therapeutic use
- Demyelinating Diseases/pathology
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Encephalomyelitis, Autoimmune, Experimental/chemically induced
- Encephalomyelitis, Autoimmune, Experimental/complications
- Encephalomyelitis, Autoimmune, Experimental/drug therapy
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Female
- Gabapentin
- Gait
- Gliosis/pathology
- Hyperalgesia/chemically induced
- Hyperalgesia/complications
- Hyperalgesia/drug therapy
- Mice
- Morphine/therapeutic use
- Multiple Sclerosis/complications
- Multiple Sclerosis/drug therapy
- Myelin-Oligodendrocyte Glycoprotein
- Neuralgia/complications
- Neuralgia/drug therapy
- Peptide Fragments
- Pertussis Toxin
- Quillaja Saponins
- gamma-Aminobutyric Acid/therapeutic use
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Affiliation(s)
- Nemat Khan
- The University of Queensland, Center for Integrated Preclinical Drug Development, St Lucia Campus, Brisbane, Queensland 4072, Australia; School of Pharmacy, The University of Queensland, Pharmacy Australia Center of Excellence, Woolloongabba, Brisbane, Queensland 4102, Australia
| | - Trent M Woodruff
- The School of Biomedical Sciences, University of Queensland, St Lucia Campus, Brisbane, Queensland 4072, Australia
| | - Maree T Smith
- The University of Queensland, Center for Integrated Preclinical Drug Development, St Lucia Campus, Brisbane, Queensland 4072, Australia; School of Pharmacy, The University of Queensland, Pharmacy Australia Center of Excellence, Woolloongabba, Brisbane, Queensland 4102, Australia.
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13
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Moxon KA, Oliviero A, Aguilar J, Foffani G. Cortical reorganization after spinal cord injury: always for good? Neuroscience 2014; 283:78-94. [PMID: 24997269 DOI: 10.1016/j.neuroscience.2014.06.056] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 06/09/2014] [Accepted: 06/25/2014] [Indexed: 12/29/2022]
Abstract
Plasticity constitutes the basis of behavioral changes as a result of experience. It refers to neural network shaping and re-shaping at the global level and to synaptic contacts remodeling at the local level, either during learning or memory encoding, or as a result of acute or chronic pathological conditions. 'Plastic' brain reorganization after central nervous system lesions has a pivotal role in the recovery and rehabilitation of sensory and motor dysfunction, but can also be "maladaptive". Moreover, it is clear that brain reorganization is not a "static" phenomenon but rather a very dynamic process. Spinal cord injury immediately initiates a change in brain state and starts cortical reorganization. In the long term, the impact of injury - with or without accompanying therapy - on the brain is a complex balance between supraspinal reorganization and spinal recovery. The degree of cortical reorganization after spinal cord injury is highly variable, and can range from no reorganization (i.e. "silencing") to massive cortical remapping. This variability critically depends on the species, the age of the animal when the injury occurs, the time after the injury has occurred, and the behavioral activity and possible therapy regimes after the injury. We will briefly discuss these dependencies, trying to highlight their translational value. Overall, it is not only necessary to better understand how the brain can reorganize after injury with or without therapy, it is also necessary to clarify when and why brain reorganization can be either "good" or "bad" in terms of its clinical consequences. This information is critical in order to develop and optimize cost-effective therapies to maximize functional recovery while minimizing maladaptive states after spinal cord injury.
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Affiliation(s)
- K A Moxon
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA.
| | - A Oliviero
- Hospital Nacional de Parapléjicos, SESCAM, Finca la Peraleda s/n, 45071 Toledo, Spain
| | - J Aguilar
- Hospital Nacional de Parapléjicos, SESCAM, Finca la Peraleda s/n, 45071 Toledo, Spain
| | - G Foffani
- Hospital Nacional de Parapléjicos, SESCAM, Finca la Peraleda s/n, 45071 Toledo, Spain.
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14
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Yagüe J, Humanes-Valera D, Aguilar J, Foffani G. Functional reorganization of the forepaw cortical representation immediately after thoracic spinal cord hemisection in rats. Exp Neurol 2014; 257:19-24. [DOI: 10.1016/j.expneurol.2014.03.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 03/07/2014] [Accepted: 03/19/2014] [Indexed: 11/28/2022]
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Widerström-Noga E. Multidimensional clinical pain phenotypes after spinal cord injury. Pain Manag 2014; 2:467-78. [PMID: 24645863 DOI: 10.2217/pmt.12.44] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
SUMMARY Persistent neuropathic pain after spinal cord injury (SCI) is a serious problem that significantly affects general health and wellbeing over and above what is caused by other medical consequences after SCI. The ideal approach to the management of the neuropathic pain conditions after SCI would be to identify the primary contributing mechanisms of pain in each person and tailor the treatment to these. However, despite significant basic and clinical research progress, this approach remains elusive. One strategy to further this effort is to define neuropathic pain phenotypes based on pain symptoms, sensory function/dysfunction and psychosocial factors, and determine the relationship between these and treatment outcomes and biomarkers including brain imaging. This approach will facilitate the interaction between basic and clinical science and translational research, further the understanding of the mechanisms that contribute to the development and maintenance of neuropathic pain after SCI, and thus the development of effective mechanisms-based pain treatment strategies.
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Affiliation(s)
- Eva Widerström-Noga
- The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami, LPLC (R-48) and Departments of Neurological Surgery & Rehabilitation Medicine, Miller School of Medicine, University of Miami, LPLC (R-48), 1095 NW, 14th Terrace Miami, FL 33136, USA.
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16
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M'Dahoma S, Bourgoin S, Kayser V, Barthélémy S, Chevarin C, Chali F, Orsal D, Hamon M. Spinal cord transection-induced allodynia in rats--behavioral, physiopathological and pharmacological characterization. PLoS One 2014; 9:e102027. [PMID: 25019623 PMCID: PMC4096923 DOI: 10.1371/journal.pone.0102027] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 06/14/2014] [Indexed: 12/31/2022] Open
Abstract
In humans, spinal cord lesions induce not only major motor and neurovegetative deficits but also severe neuropathic pain which is mostly resistant to classical analgesics. Better treatments can be expected from precise characterization of underlying physiopathological mechanisms. This led us to thoroughly investigate (i) mechanical and thermal sensory alterations, (ii) responses to acute treatments with drugs having patent or potential anti-allodynic properties and (iii) the spinal/ganglion expression of transcripts encoding markers of neuronal injury, microglia and astrocyte activation in rats that underwent complete spinal cord transection (SCT). SCT was performed at thoracic T8-T9 level under deep isoflurane anaesthesia, and SCT rats were examined for up to two months post surgery. SCT induced a marked hyper-reflexia at hindpaws and strong mechanical and cold allodynia in a limited (6 cm2) cutaneous territory just rostral to the lesion site. At this level, pressure threshold value to trigger nocifensive reactions to locally applied von Frey filaments was 100-fold lower in SCT- versus sham-operated rats. A marked up-regulation of mRNAs encoding ATF3 (neuronal injury) and glial activation markers (OX-42, GFAP, P2×4, P2×7, TLR4) was observed in spinal cord and/or dorsal root ganglia at T6-T11 levels from day 2 up to day 60 post surgery. Transcripts encoding the proinflammatory cytokines IL-1β, IL-6 and TNF-α were also markedly but differentially up-regulated at T6-T11 levels in SCT rats. Acute treatment with ketamine (50 mg/kg i.p.), morphine (3-10 mg/kg s.c.) and tapentadol (10-20 mg/kg i.p.) significantly increased pressure threshold to trigger nocifensive reaction in the von Frey filaments test, whereas amitriptyline, pregabalin, gabapentin and clonazepam were ineffective. Because all SCT rats developed long lasting, reproducible and stable allodynia, which could be alleviated by drugs effective in humans, thoracic cord transection might be a reliable model for testing innovative therapies aimed at reducing spinal cord lesion-induced central neuropathic pain.
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Affiliation(s)
- Saïd M'Dahoma
- Centre de Psychiatrie et Neurosciences, Institut National de la Santé et de la Recherche Médicale, INSERM U894, Université Paris Descartes, Paris, France
- Neuropsychopharmacologie, Faculté de Médecine Pierre et Marie Curie, site Pitié-Salpêtrière, Paris, France
- * E-mail:
| | - Sylvie Bourgoin
- Centre de Psychiatrie et Neurosciences, Institut National de la Santé et de la Recherche Médicale, INSERM U894, Université Paris Descartes, Paris, France
- Neuropsychopharmacologie, Faculté de Médecine Pierre et Marie Curie, site Pitié-Salpêtrière, Paris, France
| | - Valérie Kayser
- Centre de Psychiatrie et Neurosciences, Institut National de la Santé et de la Recherche Médicale, INSERM U894, Université Paris Descartes, Paris, France
- Neuropsychopharmacologie, Faculté de Médecine Pierre et Marie Curie, site Pitié-Salpêtrière, Paris, France
| | - Sandrine Barthélémy
- Centre de Psychiatrie et Neurosciences, Institut National de la Santé et de la Recherche Médicale, INSERM U894, Université Paris Descartes, Paris, France
- Neuropsychopharmacologie, Faculté de Médecine Pierre et Marie Curie, site Pitié-Salpêtrière, Paris, France
| | - Caroline Chevarin
- Centre de Psychiatrie et Neurosciences, Institut National de la Santé et de la Recherche Médicale, INSERM U894, Université Paris Descartes, Paris, France
- Neuropsychopharmacologie, Faculté de Médecine Pierre et Marie Curie, site Pitié-Salpêtrière, Paris, France
| | - Farah Chali
- Laboratoire de Neurobiologie des Signaux Intercellulaires, Centre National de la Recherche Scientifique, CNRS UMR 7101, Université Pierre et Marie Curie, Paris, France
| | - Didier Orsal
- Laboratoire de Neurobiologie des Signaux Intercellulaires, Centre National de la Recherche Scientifique, CNRS UMR 7101, Université Pierre et Marie Curie, Paris, France
| | - Michel Hamon
- Centre de Psychiatrie et Neurosciences, Institut National de la Santé et de la Recherche Médicale, INSERM U894, Université Paris Descartes, Paris, France
- Neuropsychopharmacologie, Faculté de Médecine Pierre et Marie Curie, site Pitié-Salpêtrière, Paris, France
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17
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Sydekum E, Ghosh A, Gullo M, Baltes C, Schwab M, Rudin M. Rapid functional reorganization of the forelimb cortical representation after thoracic spinal cord injury in adult rats. Neuroimage 2013; 87:72-9. [PMID: 24185021 DOI: 10.1016/j.neuroimage.2013.10.045] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 09/30/2013] [Accepted: 10/21/2013] [Indexed: 11/28/2022] Open
Abstract
Thoracic spinal cord injured rats rely largely on forelimbs to walk, as their hindlimbs are dysfunctional. This increased limb use is accompanied by expansion of the cortical forelimb sensory representation. It is unclear how quickly the representational changes occur and whether they are at all related to the behavioral adaptation. Using blood oxygenation level dependent functional mangetic resonance imaging (BOLD-fMRI) we show that major plastic changes of the somato-sensory map can occur as early as one day after injury. The extent of map increase was variable between animals, and some animals showed a reduction in map size. However, at three or seven days after injury a significant enhancement of the forelimb representation was evident in all the animals. In a behavioral test for precise limb control, crossing of a horizontal ladder, the injured rats relied almost entirely on their forelimbs; they initially made more mistakes than at 7 days post injury. Remarkably, in the individual animals the behavioral performance seen at seven days was proportional to the physiological change present at one day after injury. The rapid increase in cortical representation of the injury-spared body part may provide the additional neural substrate necessary for high level behavioral adaptation.
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Affiliation(s)
- Esther Sydekum
- Institute for Biomedical Engineering, University of Zurich, Switzerland; ETH Zurich, Switzerland
| | - Arko Ghosh
- Institute of Neuroinformatics, University of Zurich, Switzerland; Center for Neuroscience Zurich, University of Zurich and ETH Zurich, Switzerland; Institute of Cognitive Neuroscience, University College London, UK; ETH Zurich, Switzerland.
| | - Miriam Gullo
- Brain Research Institute, University of Zurich, Switzerland; ETH Zurich, Switzerland
| | - Christof Baltes
- Institute for Biomedical Engineering, University of Zurich, Switzerland; ETH Zurich, Switzerland
| | - Martin Schwab
- Center for Neuroscience Zurich, University of Zurich and ETH Zurich, Switzerland; Brain Research Institute, University of Zurich, Switzerland; ETH Zurich, Switzerland
| | - Markus Rudin
- Institute for Biomedical Engineering, University of Zurich, Switzerland; Center for Neuroscience Zurich, University of Zurich and ETH Zurich, Switzerland; Institute for Pharmacology and Toxicology, University of Zurich, Switzerland; ETH Zurich, Switzerland.
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18
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Effects of gabapentin on thermal sensitivity following spinal nerve ligation or spinal cord compression. Behav Pharmacol 2013; 24:598-609. [DOI: 10.1097/fbp.0b013e3283656d9b] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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19
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Guptarak J, Wanchoo S, Durham-Lee J, Wu Y, Zivadinovic D, Paulucci-Holthauzen A, Nesic O. Inhibition of IL-6 signaling: A novel therapeutic approach to treating spinal cord injury pain. Pain 2013; 154:1115-28. [PMID: 23639820 DOI: 10.1016/j.pain.2013.03.026] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 02/03/2013] [Accepted: 03/15/2013] [Indexed: 01/13/2023]
Abstract
To characterize the contribution of interleukin-6 (IL-6) to spinal cord injury pain (SCIP), we employed a clinically relevant rat contusion model of SCIP. Using Western blots, we measured IL-6 levels in lumbar segments (L1-L5), at the lesion site (T10), and in the corresponding lumbar and thoracic dorsal root ganglia (DRG) in 2 groups of similarly injured rats: (a) SCI rats that developed hind-limb mechanical allodynia (SCIP), and (b) SCI rats that did not develop SCIP. Only in SCIP rats did we find significantly increased IL-6 levels. Immunocytochemistry showed elevated IL-6 predominantly in reactive astrocytes. Our data also showed that increased production of IL-6 in hyperreactive astrocytes in SCIP rats may explain still-poorly understood astrocytic contribution to SCIP. To test the hypothesis that IL-6 contributes to mechanical allodynia, we treated SCIP rats with neutralizing IL-6 receptor antibody (IL-6-R Ab), and found that one systemic injection abolished allodynia and associated weight loss; in contrast to gabapentin, the analgesic effect lasted for at least 2weeks after the injection, despite the shorter presence of the Ab in the circulation. We also showed that IL-6-R Ab partially reversed SCI-induced decreases in the protein levels of the glutamate transporter GLT-1 12hours and 8days after Ab injection, which may explain the lasting analgesic effect of the Ab in SCIP rats. A link between reactive astrocytes IL-6-GLT-1 has not been previously shown. Given that the humanized IL-6-R Ab tocilizumab is Food and Drug Administration-approved for rheumatoid arthritis, we are proposing tocilizumab as a novel and potentially effective treatment for SCIP.
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Affiliation(s)
- Jutatip Guptarak
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555-1072, USA
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Xifró X, Puig T, Boadas-Vaello P. Diagnóstico y tratamiento farmacológico del dolor neuropático del lesionado medular: del laboratorio a la clínica. Med Clin (Barc) 2013. [DOI: 10.1016/j.medcli.2012.09.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
This paper is the thirty-fourth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2011 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration (Section 16); and immunological responses (Section 17).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY 11367, United States.
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Stolz ED, Viana AF, Hasse DR, von Poser GL, do Rego JC, Rates SMK. Uliginosin B presents antinociceptive effect mediated by dopaminergic and opioid systems in mice. Prog Neuropsychopharmacol Biol Psychiatry 2012; 39:80-7. [PMID: 22627196 DOI: 10.1016/j.pnpbp.2012.05.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 05/03/2012] [Accepted: 05/15/2012] [Indexed: 12/16/2022]
Abstract
Previous studies have shown that uliginosin B inhibits dopamine reuptake in rat brain. This compound occurs in Hypericum polyanthemum and H. caprifoliatum for which was reported to have antinociceptive effect sensitive to naloxone. The aim of this study was to assess the antinociceptive effect of uliginosin B and to evaluate the involvement of opioid and dopaminergic receptors activation. Uliginosin B presented antinociceptive effect in hot-plate and abdominal writhing tests, in mice, at doses that did not impair the motor coordination (15 mg/kg, i.p.). Uliginosin B in high dose (90 mg/kg, i.p.) presented ataxic effect in the rotarod apparatus. These effects seem to be mediated by distinct receptors since the effect on the hot-plate was completely abolished by naloxone and sulpiride, but it was unaffected by SCH 23390. On the other hand, the motor impairment induced by uliginosin B was completely prevented by naloxone and partially prevented by sulpiride and SCH 23390. However, the receptors' activation appears to be indirect since uliginosin B did not bind to opioid and dopaminergic receptors. Thus, uliginosin B effects probably are due to its ability to inhibit monoamine reuptake with consequent activation of dopamine receptors and indirect stimulation of opioid system.
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Affiliation(s)
- Eveline Dischkaln Stolz
- Programa de Pós-Graduação em Neurociências, Universidade Federal do Rio Grande do Sul, Avenida Ipiranga 2752/505c, 90610-000 Porto Alegre, RS, Brazil
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Walters ET. Nociceptors as chronic drivers of pain and hyperreflexia after spinal cord injury: an adaptive-maladaptive hyperfunctional state hypothesis. Front Physiol 2012; 3:309. [PMID: 22934060 PMCID: PMC3429080 DOI: 10.3389/fphys.2012.00309] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2012] [Accepted: 07/13/2012] [Indexed: 11/13/2022] Open
Abstract
Spinal cord injury (SCI) causes chronic peripheral sensitization of nociceptors and persistent generation of spontaneous action potentials (SA) in peripheral branches and the somata of hyperexcitable nociceptors within dorsal root ganglia (DRG). Here it is proposed that SCI triggers in numerous nociceptors a persistent hyperfunctional state (peripheral, synaptic, and somal) that originally evolved as an adaptive response to compensate for loss of sensory terminals after severe but survivable peripheral injury. In this hypothesis, nociceptor somata monitor the status of their own receptive field and the rest of the body by integrating signals received by their peripheral and central branches and the soma itself. A nociceptor switches into a potentially permanent hyperfunctional state when central neural, glial, and inflammatory signal combinations are detected that indicate extensive peripheral injury. Similar signal combinations are produced by SCI and disseminated widely to uninjured as well as injured nociceptors. This paper focuses on the uninjured nociceptors that are altered by SCI. Enhanced activity generated in below-level nociceptors promotes below-level central sensitization, somatic and autonomic hyperreflexia, and visceral dysfunction. If sufficient ascending fibers survive, enhanced activity in below-level nociceptors contributes to below-level pain. Nociceptor activity generated above the injury level contributes to at- and above-level sensitization and pain (evoked and spontaneous). Thus, SCI triggers a potent nociceptor state that may have been adaptive (from an evolutionary perspective) after severe peripheral injury but is maladaptive after SCI. Evidence that hyperfunctional nociceptors make large contributions to behavioral hypersensitivity after SCI suggests that nociceptor-specific ion channels required for nociceptor SA and hypersensitivity offer promising targets for treating chronic pain and hyperreflexia after SCI.
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Affiliation(s)
- Edgar T Walters
- Department of Integrative Biology and Pharmacology, University of Texas Medical School at Houston Houston, TX, USA
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Finnerup NB, Baastrup C. Spinal Cord Injury Pain: Mechanisms and Management. Curr Pain Headache Rep 2012; 16:207-16. [PMID: 22392531 DOI: 10.1007/s11916-012-0259-x] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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25
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Grimpe B. Deoxyribozymes and bioinformatics: complementary tools to investigate axon regeneration. Cell Tissue Res 2011; 349:181-200. [PMID: 22190188 PMCID: PMC7087747 DOI: 10.1007/s00441-011-1291-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 11/17/2011] [Indexed: 11/28/2022]
Abstract
For over 100 years, scientists have tried to understand the mechanisms that lead to the axonal growth seen during development or the lack thereof during regeneration failure after spinal cord injury (SCI). Deoxyribozyme technology as a potential therapeutic to treat SCIs or other insults to the brain, combined with a bioinformatics approach to comprehend the complex protein-protein interactions that occur after such trauma, is the focus of this review. The reader will be provided with information on the selection process of deoxyribozymes and their catalytic sequences, on the mechanism of target digestion, on modifications, on cellular uptake and on therapeutic applications and deoxyribozymes are compared with ribozymes, siRNAs and antisense technology. This gives the reader the necessary knowledge to decide which technology is adequate for the problem at hand and to design a relevant agent. Bioinformatics helps to identify not only key players in the complex processes that occur after SCI but also novel or less-well investigated molecules against which new knockdown agents can be generated. These two tools used synergistically should facilitate the pursuit of a treatment for insults to the central nervous system.
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Affiliation(s)
- Barbara Grimpe
- Applied Neurobiology, Department of Neurology, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany.
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26
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The animal model of spinal cord injury as an experimental pain model. J Biomed Biotechnol 2011; 2011:939023. [PMID: 21436995 PMCID: PMC3062973 DOI: 10.1155/2011/939023] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 12/19/2010] [Indexed: 12/25/2022] Open
Abstract
Pain, which remains largely unsolved, is one of the most crucial problems for spinal cord injury patients. Due to sensory problems, as well as motor dysfunctions, spinal cord injury research has proven to be complex and difficult. Furthermore, many types of pain are associated with spinal cord injury, such as neuropathic, visceral, and musculoskeletal pain. Many animal models of spinal cord injury exist to emulate clinical situations, which could help to determine common mechanisms of pathology. However, results can be easily misunderstood and falsely interpreted. Therefore, it is important to fully understand the symptoms of human spinal cord injury, as well as the various spinal cord injury models and the possible pathologies. The present paper summarizes results from animal models of spinal cord injury, as well as the most effective use of these models.
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27
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Davis MP. Opioid tolerance and hyperalgesia: basic mechanisms and management in review. PROGRESS IN PALLIATIVE CARE 2011. [DOI: 10.1179/174329111x13045147380537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Yague JG, Foffani G, Aguilar J. Cortical hyperexcitability in response to preserved spinothalamic inputs immediately after spinal cord hemisection. Exp Neurol 2010; 227:252-63. [PMID: 21093438 DOI: 10.1016/j.expneurol.2010.11.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Accepted: 11/09/2010] [Indexed: 01/27/2023]
Abstract
Chronic injury of the main somatosensory pathways ascending along the spinal cord - the dorsal columns and the spinothalamic tract - can produce both changes in the organization of cortical somatotopic maps and neuropathic pain. Little is known, however, about the early neurophysiological changes occurring immediately after injury. We bilaterally recorded the neural activity of the hindpaw representation of the primary somatosensory cortex evoked by stimuli delivered to the hindpaws before and immediately after a thoracic spinal cord hemisection in anesthetized rats. This unilateral spinal cord injury allowed us to separately investigate the cortical effects of deafferenting the dorsal column (stimuli ipsilateral to the hemisection) or the spinothalamic tract (stimuli contralateral to the hemisection). The hemisection produced immediate bilateral changes in the cortical responses evoked by stimuli delivered to the hindpaw ipsilateral to the hemisection (deafferented dorsal column): an expected loss of classical short-latency cortical responses, accompanied by an unexpected appearance of long-latency activations. At the population level, these activations reflected a progressive stimulus-induced transition of the hindpaw somatosensory cortex from up-and-down states to a sustained activated state. At the single-cell level, these cortical activations resembled the "wind-up" typically observed - with the same type of stimuli - in the dorsal horn cells originating the spinothalamic tract. Virtually no changes were observed in the responses evoked by stimuli delivered to the hindpaw contralateral to the hemisection (deafferented spinothalamic tract). These results suggest that spinal cord hemisection immediately produces an abnormal hyperexcitability of the primary somatosensory cortex in response to preserved spinothalamic inputs from the hindpaw. This immediate cortical hyperexcitability could be important to understand the long-term development of cortical reorganization and neuropathic pain after incomplete spinal cord lesions.
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Affiliation(s)
- J G Yague
- Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain
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