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Meng FX, Hou JM, Sun TS. Effect of oxidative stress induced by intracranial iron overload on central pain after spinal cord injury. J Orthop Surg Res 2017; 12:24. [PMID: 28178997 PMCID: PMC5299723 DOI: 10.1186/s13018-017-0526-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 01/28/2017] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Central pain (CP) is a common clinical problem in patients with spinal cord injury (SCI). Recent studies found the pathogenesis of CP was related to the remodeling of the brain. We investigate the roles of iron overload and subsequent oxidative stress in the remodeling of the brain after SCI. METHODS We established a rat model of central pain after SCI. Rats were divided randomly into four groups: SCI, sham operation, SCI plus deferoxamine (DFX) intervention, and SCI plus nitric oxide synthase (NOS) inhibitor treatment. Pain behavior was observed and thermal pain threshold was measured regularly, and brain levels of iron, transferrin receptor 1 (TfR1), ferritin (Fn), and lactoferrin (Lf), were detected in the different groups 12 weeks after establishment of the model. RESULTS Rats demonstrated self-biting behavior after SCI. Furthermore, the latent period of thermal pain was reduced and iron levels in the hind limb sensory area, hippocampus, and thalamus increased after SCI. Iron-regulatory protein (IRP) 1 levels increased in the hind limb sensory area, while Fn levels decreased. TfR1 mRNA levels were also increased and oxidative stress was activated. Oxidative stress could be inhibited by ferric iron chelators and NOS inhibitors. CONCLUSIONS SCI may cause intracranial iron overload through the NOS-iron-responsive element/IRP pathway, resulting in central pain mediated by the oxidative stress response. Iron chelators and oxidative stress inhibitors can effectively relieve SCI-associated central pain.
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Affiliation(s)
- Fan Xing Meng
- Third Military Medical University, No. 30 Gaotanyan Street, 400038 Chongqing, China
- Department of Orthopedics, Chinese PLA Army General Hospital, Dongcheng District, Nanmencang No. 5, 100700 Beijing, China
| | - Jing Ming Hou
- Department of Orthopedics, Chinese PLA Army General Hospital, Dongcheng District, Nanmencang No. 5, 100700 Beijing, China
- Southwest Hospital, Third Military Medical University, No. 30 Gaotanyan Street, 400038 Chongqing, China
| | - Tian Sheng Sun
- Third Military Medical University, No. 30 Gaotanyan Street, 400038 Chongqing, China
- Department of Orthopedics, Chinese PLA Army General Hospital, Dongcheng District, Nanmencang No. 5, 100700 Beijing, China
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Eguchi R, Akao S, Otsuguro KI, Yamaguchi S, Ito S. Different mechanisms of extracellular adenosine accumulation by reduction of the external Ca(2+) concentration and inhibition of adenosine metabolism in spinal astrocytes. J Pharmacol Sci 2015; 128:47-53. [PMID: 26003082 DOI: 10.1016/j.jphs.2015.04.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 03/26/2015] [Accepted: 04/21/2015] [Indexed: 12/11/2022] Open
Abstract
Extracellular adenosine is a neuromodulator in the central nervous system. Astrocytes mainly participate in adenosine production, and extracellular adenosine accumulates under physiological and pathophysiological conditions. Inhibition of intracellular adenosine metabolism and reduction of the external Ca(2+) concentration ([Ca(2+)]e) participate in adenosine accumulation, but the precise mechanisms remain unclear. This study investigated the mechanisms underlying extracellular adenosine accumulation in cultured rat spinal astrocytes. The combination of adenosine kinase and deaminase (ADK/ADA) inhibition and a reduced [Ca(2+)]e increased the extracellular adenosine level. ADK/ADA inhibitors increased the level of extracellular adenosine but not of adenine nucleotides, which was suppressed by inhibition of equilibrative nucleoside transporter (ENT) 2. Unlike ADK/ADA inhibition, a reduced [Ca(2+)]e increased the extracellular level not only of adenosine but also of ATP. This adenosine increase was enhanced by ENT2 inhibition, and suppressed by sodium polyoxotungstate (ecto-nucleoside triphosphate diphosphohydrolase inhibitor). Gap junction inhibitors suppressed the increases in adenosine and adenine nucleotide levels by reduction of [Ca(2+)]e. These results indicate that extracellular adenosine accumulation by ADK/ADA inhibition is due to the adenosine release via ENT2, while that by reduction of [Ca(2+)]e is due to breakdown of ATP released via gap junction hemichannels, after which ENT2 incorporates adenosine into the cells.
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Affiliation(s)
- Ryota Eguchi
- Laboratory of Pharmacology, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo 060-0818, Japan
| | - Sanae Akao
- Laboratory of Pharmacology, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo 060-0818, Japan
| | - Ken-ichi Otsuguro
- Laboratory of Pharmacology, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo 060-0818, Japan.
| | - Soichiro Yamaguchi
- Laboratory of Pharmacology, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo 060-0818, Japan
| | - Shigeo Ito
- Laboratory of Pharmacology, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo 060-0818, Japan
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Onifer SM, Rabchevsky AG, Scheff SW. Rat Models of Traumatic Spinal Cord Injury to Assess Motor Recovery. ILAR J 2007; 48:385-95. [PMID: 17712224 DOI: 10.1093/ilar.48.4.385] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Devastating motor, sensory, and autonomic dysfunctions render long-term personal hardships to the survivors of traumatic spinal cord injury (SCI). The suffering also extends to the survivors' families and friends, who endure emotional, physical, and financial burdens in providing for necessary surgeries, care, and rehabilitation. After the primary mechanical SCI, there is a complex secondary injury cascade that leads to the progressive death of otherwise potentially viable axons and cells and that impairs endogenous recovery processes. Investigations of possible cures and of ways to alleviate the hardships of traumatic SCI include those of interventions that attenuate or overcome the secondary injury cascade, enhance the endogenous repair mechanisms, regenerate axons, replace lost cells, and rehabilitate. These investigations have led to the creation of laboratory animal models of the different types of traumatic human SCI and components of the secondary injury cascade. However, no particular model completely addresses all aspects of traumatic SCI. In this article, we describe adult rat SCI models and the motor, and in some cases sensory and autonomic, deficits that each produces. Importantly, as researchers in this area move toward clinical trials to alleviate the hardships of traumatic SCI, there is a need for standardized small and large animal SCI models as well as quantitative behavioral and electrophysiological assessments of their outcomes so that investigators testing various interventions can directly compare their results and correlate them with the molecular, biochemical, and histological alterations.
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Affiliation(s)
- Stephen M Onifer
- Spinal Cord and Brain Injury Research Center, Biomedical and Biological Sciences Research Building, University of Kentucky, 741 South Limestone Street, Lexington, KY 40536-0509, USA.
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Ribeiro CAJ, Grando V, Dutra Filho CS, Wannmacher CMD, Wajner M. Evidence that quinolinic acid severely impairs energy metabolism through activation of NMDA receptors in striatum from developing rats. J Neurochem 2006; 99:1531-42. [PMID: 17230642 DOI: 10.1111/j.1471-4159.2006.04199.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
In the present study we investigated the effect of intrastriatal administration of 150 nmol quinolinic acid to young rats on critical enzyme activities of energy production and transfer, as well as on 14CO2 production from [1-14C]acetate at distinct periods after quinolinic acid injection. We observed that quinolinic acid injection significantly inhibited complexes II (50%), III (46%) and II-III (35%), as well as creatine kinase (27%), but not the activities of complexes I and IV and citrate synthase in striatum prepared 12 h after treatment. In contrast, no alterations of these enzyme activities were observed 3 or 6 h after quinolinic acid administration. 14CO2 production from [1-14C]acetate was also significantly inhibited (27%) by quinolinic acid in rat striatum prepared 12 h after injection. However, no alterations of these activities were observed in striatum homogenates incubated in the presence of 100 microm quinolinic acid . Pretreatment with the NMDA receptor antagonist MK-801 and with creatine totally prevented all inhibitory effects elicited by quinolinic acid administration. In addition, alpha-tocopherol plus ascorbate and the nitric oxide synthase inhibitor l-NAME completely abolished the inhibitions provoked by quinolinic acid on creatine kinase and complex III. Furthermore, pyruvate pretreatment totally blocked the inhibitory effects of quinolinic acid injection on complex II activity and partially prevented quinolinic acid-induced creatine kinase inhibition. These observations strongly indicate that oxidative phosphorylation, the citric acid cycle and cellular energy transfer are compromised by high concentrations of quinolinic acid in the striatum of young rats and that these inhibitory effects were probably mediated by NMDA stimulation.
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Affiliation(s)
- César A J Ribeiro
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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Liu D, Ling X, Wen J, Liu J. The role of reactive nitrogen species in secondary spinal cord injury: formation of nitric oxide, peroxynitrite, and nitrated protein. J Neurochem 2000; 75:2144-54. [PMID: 11032904 DOI: 10.1046/j.1471-4159.2000.0752144.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To determine whether reactive nitrogen species contribute to secondary damage in CNS injury, the time courses of nitric oxide, peroxynitrite, and nitrotyrosine production were measured following impact injury to the rat spinal cord. The concentration of nitric oxide measured by a nitric oxide-selective electrode dramatically increased immediately following injury and then quickly declined. Nitro-L-arginine reduced nitric oxide production. The extracellular concentration of peroxynitrite, measured by perfusing tyrosine through a microdialysis fiber into the cord and quantifying nitrotyrosine in the microdialysates, significantly increased after injury to 3.5 times the basal level, and superoxide dismutase and nitro-L-arginine completely blocked peroxynitrite production. Tyrosine nitration examined immunohistochemically significantly increased at 12 and 24 h postinjury, but not in sham-control sections. Mn(III) tetrakis(4-benzoic acid)-porphyrin (a novel cell-permeable superoxide dismutase mimetic) and nitro-L-arginine significantly reduced the numbers of nitrotyrosine-positive cells. Protein-bound nitrotyrosine was significantly higher in the injured tissue than in the sham-operated controls. These results demonstrate that traumatic injury increases nitric oxide and peroxynitrite production, thereby nitrating tyrosine, including protein-bound tyrosine. Together with our previous report that trauma increases superoxide, our results suggest that reactive nitrogen species cause secondary damage by nitrating protein through the pathway superoxide + nitric oxide peroxynitrite protein nitration.
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Affiliation(s)
- D Liu
- Department of Neurology, University of Texas Medical Branch, Galveston, Texas 77555-0653, USA.
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de Mendonça A, Sebastião AM, Ribeiro JA. Adenosine: does it have a neuroprotective role after all? BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 2000; 33:258-74. [PMID: 11011069 DOI: 10.1016/s0165-0173(00)00033-3] [Citation(s) in RCA: 200] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A neuroprotective role for adenosine is commonly assumed. Recent studies revealed that adenosine may unexpectedly, under certain circumstances, have the opposite effects contributing to neuronal damage and death. The basis for this duality may be the activation of distinct subtypes of adenosine receptors, interactions between these receptors, differential actions on neuronal and glial cells, and various time frames of adenosinergic compounds administration. If these aspects are understood, adenosine should remain an interesting target for therapeutical neuroprotective approaches after all.
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Affiliation(s)
- A de Mendonça
- Laboratory of Neurosciences, Faculty of Medicine of Lisbon, Av. Professor Egas Moniz, 1649-035, Lisbon, Portugal.
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Abstract
The hypothesis that release of adenosine following spinal cord injury (SCI) may provide neuroprotective feedback is explored. Consistent with this hypothesis, substantial release of adenosine, estimated to reach 100 microM in the extracellular space, was detected by microdialysis sampling immediately following contusion SCI. There is also considerable release of excitatory amino acids following SCI. The latter was not affected by administration of the general adenosine receptor antagonist theophylline and the A1 antagonist 8-cyclopentyl-1,3-dipropylxanthine, implying that the adenosine released following SCI does not significantly influence the release of neurotoxic amino acids. Administration of the concentration of glutamate released upon SCI into the spinal cord caused only about 1% as much release of adenosine as did injury, evidence that elevated excitatory amino acids do not elicit an appreciable fraction of the release of adenosine that follows SCI. Results obtained suggest that release of endogenous adenosine is not neuroprotective by blocking release of excitatory amino acids following SCI.
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Affiliation(s)
- D J McAdoo
- Marine Biomedical Institute, University of Texas Medical Branch, Galveston 77555-1069, USA.
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Brewer KL, Bethea JR, Yezierski RP. Neuroprotective effects of interleukin-10 following excitotoxic spinal cord injury. Exp Neurol 1999; 159:484-93. [PMID: 10506519 DOI: 10.1006/exnr.1999.7173] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Intraspinal injection of quisqualic acid (QUIS) produces excitotoxic injury with pathological characteristics similar to those associated with ischemic and traumatic spinal cord injury (SCI). Inflammatory responses appear to be a major component of the secondary neuronal injury initiated by SCI and play a role in the pathogenesis of QUIS-induced injury. IL-10 is a potent antiinflammatory cytokine that has been shown to reduce inflammation and improve functional outcome in human and animal models of inflammatory diseases. We propose the administration of IL-10 following excitotoxic SCI will attenuate the inflammatory response, thus resulting in increased neuronal survival. Female, Sprague-Dawley rats were given intraspinal injections of QUIS followed by either intraspinal (5 ng, n = 8) or systemic injections (5 microgram n = 14) of IL-10. Survival times were varied (2-3 days) in order to produce a range of injury states and inflammatory involvement. When administered intraspinally, IL-10 significantly exacerbated the QUIS damage (P < 0.05), resulting in an 11.2% increase in lesion volume. When given systemically, IL-10 significantly decreased lesion volume by 18.1% in the more advanced injury (P < 0.05), but did not effect the more acute injury. These divergent effects were attributed to the modest inflammatory response in the short-term injury compared to the more robust inflammatory response in the more chronic injury. In conclusion, reducing the inflammatory response to SCI by systemic administration of IL-10 resulted in a significant reduction in neuronal damage, suggesting that targeting injury-induced inflammation may be an effective treatment strategy for acute SCI.
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Affiliation(s)
- K L Brewer
- Department of Anatomy and Cell Biology, East Carolina University, 27858, USA
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