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Yeo JH, Roh DH. The mTOR inhibitor rapamycin suppresses trigeminal neuropathic pain and p-MKK4/p-p38 mitogen-activated protein kinase-mediated microglial activation in the trigeminal nucleus caudalis of mice with infraorbital nerve injury. Front Mol Neurosci 2023; 16:1172366. [PMID: 37122619 PMCID: PMC10140572 DOI: 10.3389/fnmol.2023.1172366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 03/27/2023] [Indexed: 05/02/2023] Open
Abstract
Neuropathic pain caused by trigeminal nerve injury is a typical refractory orofacial chronic pain accompanied by the development of hyperalgesia and allodynia. We previously demonstrated that the mammalian target of rapamycin (mTOR) inhibitor rapamycin suppressed orofacial formalin injection-induced nociception; however, the underlying mechanism is unclear, and it is unknown whether it can reduce trigeminal neuropathic pain. In mice, left infraorbital nerve and partial nerve ligation (ION-pNL) was performed using a silk suture (8-0). Fourteen days after surgery, neuropathic pain behavior was examined on a whisker pad and rapamycin (0.1, 0.3, and 1.0 mg/kg) was administered intraperitoneally. Mechanical and cold sensitivities in the orofacial region were quantified using von Frey filaments and acetone solution, respectively. Changes in mTOR and related proteins, such as p-MKK3/6, p-MKK4, p-JNK, p-ERK, p-p38 MAPK, GFAP, and Iba-1, in the trigeminal nucleus caudalis (TNC) or the trigeminal ganglia (TG) tissues were examined via western blot analysis or immunohistochemistry. Mice demonstrated significant mechanical and cold allodynia 2 weeks following ION-pNL injury, both of which were significantly reduced 1 h after the administration of high-dose rapamycin (1.0 mg/kg). In the TG tissue, ION-pNL surgery or rapamycin treatment did not change p-mTOR and p-4EBP1, but rapamycin reduced the increase of p-S6 and S6 induced by ION-pNL. In the TNC tissue, neither ION-pNL surgery nor rapamycin treatment altered p-mTOR, p-S6, and p-4EBP1 expressions, whereas rapamycin significantly decreased the ION-pNL-induced increase in Iba-1 expression. In addition, rapamycin suppressed the increase in p-p38 MAPK and p-MKK4 expressions but not p-MKK3/6 expression. Moreover, p-p38 MAPK-positive cells were colocalized with increased Iba-1 in the TNC. Our findings indicate that rapamycin treatment reduces both mechanical and cold orofacial allodynia in mice with trigeminal neuropathic pain, which is closely associated with the modulation of p-MKK4/p-p38 MAPK-mediated microglial activation in the TNC.
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Differential Activation of pERK1/2 and c-Fos Following Injury to Different Regions of Primary Sensory Neuron. Life (Basel) 2022; 12:life12050752. [PMID: 35629419 PMCID: PMC9147482 DOI: 10.3390/life12050752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/15/2022] [Accepted: 05/17/2022] [Indexed: 12/30/2022] Open
Abstract
Nerve injury causes hyperexcitability of the dorsal root ganglion (DRG) and spinal dorsal horn (DH) neurons, which results in neuropathic pain. We have previously demonstrated that partial dorsal rhizotomy (PDR) produced less severe pain-like behavior than chronic constriction injury (CCI) or chronic compression of DRG (CCD) and did not enhance DRG neuronal excitability. However, the mechanisms underlying such discrepancy remain unclear. This study was designed to compare the activation of phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2) in DRG and DH, and c-Fos in DH following treatments of CCI, CCD, and PDR. We confirmed that thermal hyperalgesia produced by PDR was less severe than that produced by CCI or CCD. We showed that pERK1/2 in DRG and DH was greatly activated by CCI or CCD, whereas PDR produced only transient and mild pERK1/2 activation. CCI, CCD, and PDR induced robust c-Fos expression in DH; nevertheless, c-Fos+ neurons following PDR were much fewer than that following CCI or CCD. Blocking retrograde axonal transport by colchicine proximal to the CCI injury site diminished thermal hyperalgesia and inhibited pERK1/2 and c-Fos activation. These findings demonstrate that less severe pain-like behavior produced by PDR than CCI or CCD attributes to less activation of pERK1/2 and c-Fos. Such neurochemical activation partially relies on retrograde axonal transport of certain “injury signals” from the peripheral injured site to DRG somata.
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Terayama R, Uchibe K. Reorganization of synaptic inputs to spinal dorsal horn neurons in neuropathic pain. Int J Neurosci 2021; 132:1210-1216. [PMID: 33428497 DOI: 10.1080/00207454.2021.1873980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Peripheral nerve injuries produce a variety of negative structural and functional changes in the central terminal sites of damaged axons, as well as the injured primary afferents. Such changes have been shown to be involved in the development of neuropathic pain, which includes abnormal pain sensations such as allodynia and hyperalgesia. Since the spinal dorsal horn is the first central site where signals from peripheral sensory nerves are transmitted and shows a variety of changes after peripheral nerve injury or chronic inflammation of peripheral tissues, it is one of the most important sites contributing to the mechanisms underlying the development of neuropathic pain. The functional disruption of inhibitory interneurons and glial activation in the spinal dorsal horn after peripheral nerve injury cause reorganization of neuronal circuits and changes in the excitability of second-order neurons. These events are involved in the development or maintenance of neuropathic pain. Here, we describe the interactions of primary afferents, interneurons, and glial cells that may cause reorganization of synaptic inputs to spinal dorsal horn neurons after peripheral nerve injury.
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Affiliation(s)
- Ryuji Terayama
- Department of Maxillofacial Anatomy and Neuroscience, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Kenta Uchibe
- Department of Maxillofacial Anatomy and Neuroscience, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
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Zhang Y, Zhang X, Xing Z, Tang S, Chen H, Zhang Z, Li J, Li Y. circStrn3 is involved in bone cancer pain regulation in a rat model. Acta Biochim Biophys Sin (Shanghai) 2020; 52:495-505. [PMID: 32395748 PMCID: PMC7270972 DOI: 10.1093/abbs/gmaa018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 03/06/2020] [Accepted: 03/09/2020] [Indexed: 12/14/2022] Open
Abstract
Bone cancer pain (BCP) is a common chronic pain that is caused by a primary or metastatic bone tumor. More detailed molecular mechanisms of BCP are warranted. In this study, we established a BCP rat model. The von Frey hair test, body weight, and hematoxylin and eosin staining were employed. We screened differentially expressed circRNAs (DECs) between the BCP group and sham group. The results revealed that 850 DECs were significantly up-regulated and 644 DECs were significantly down-regulated in the BCP group. Furthermore, we identified 1177 differentially expressed genes (DEGs) significantly up-regulated and 565 DEGs significantly down-regulated in the BCP group. Gene Ontology annotation of all 1742 DEGs revealed that biological regulation of metabolic processes, cellular processes, and binding were the top enriched terms. For Kyoto Encyclopedia of Genes and Genomes analysis, phagosome, HTLV-I infection, proteoglycans in cancer, and herpes simplex infection were significantly enriched in this study. In addition, we identified four selected circRNAs, chr6:72418120|72430205, chr20:7561057|7573740, chr18:69943105|69944476, and chr5:167516581|167558250, by quantitative real time PCR. chr6:72418120|72430205 (circStrn3) was selected for further study based on expression level and the circRNA–miRNA–mRNA network table. Western blot analysis suggested that knockdown of circStrn3 could effectively induce Walker 256 cell apoptosis. In summary, our study provided a more in-depth understanding of the molecular mechanisms of BCP.
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Affiliation(s)
- Yiwen Zhang
- Department of Anesthesiology, The First Affiliated Hospital of Jinan University, Guangzhou 510632, China
- Department of Anesthesiology, Shunde Hospital of Southern Medical University (The First People’s Hospital of Shunde Foshan), Foshan 528308, China
| | - Xiaoxia Zhang
- Department of Anesthesiology, Shunde Hospital of Southern Medical University (The First People’s Hospital of Shunde Foshan), Foshan 528308, China
| | - Zumin Xing
- Department of Anesthesiology, Shunde Hospital of Southern Medical University (The First People’s Hospital of Shunde Foshan), Foshan 528308, China
| | - Shuyi Tang
- Department of Anesthesiology, Shunde Hospital of Southern Medical University (The First People’s Hospital of Shunde Foshan), Foshan 528308, China
| | - Hanwen Chen
- Department of Anesthesiology, Shunde Hospital of Southern Medical University (The First People’s Hospital of Shunde Foshan), Foshan 528308, China
| | - Zhongqi Zhang
- Department of Anesthesiology, Shunde Hospital of Southern Medical University (The First People’s Hospital of Shunde Foshan), Foshan 528308, China
| | - Jiyuan Li
- Department of Anesthesiology, Shunde Hospital of Southern Medical University (The First People’s Hospital of Shunde Foshan), Foshan 528308, China
| | - Yalan Li
- Department of Anesthesiology, The First Affiliated Hospital of Jinan University, Guangzhou 510632, China
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Yin Y, Guo R, Shao Y, Ge M, Miao C, Cao L, Yang Y, Hu L. Pretreatment with resveratrol ameliorate trigeminal neuralgia by suppressing matrix metalloproteinase-9/2 in trigeminal ganglion. Int Immunopharmacol 2019; 72:339-347. [PMID: 31009895 DOI: 10.1016/j.intimp.2019.04.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 03/29/2019] [Accepted: 04/05/2019] [Indexed: 01/05/2023]
Abstract
Trigeminal neuralgia (TN) is a common type of neuropathic pain whereas the underlying pathogenesis has not been completely elucidated. Recent study suggests that the development of neuroinflammation is responsible for generating and sustaining neuropathic pain. The purpose of our study was to investigate the protective effect of intervening the inflammation in early stages of pain and explore its potential mechanism. MMP-9 and MMP-2 are vital proinflammatory participants and accumulating evidence indicates that they are involved in the early development of neuropathic pain. In this study, we found that MMP-9/2 showed different temporal up regulation in trigeminal ganglion (TG) significantly after chronic constriction injury (CCI) surgery. However, the activation of MMP-9/2 were suppressed by the pretreatment with resveratrol, which delayed and attenuated CCI-induced mechanical allodynia simultaneously. Besides, the expression of proinflammatory cytokines like IL-1β and TNF-α as well as the excessive neuronal activity induced by CCI were suppressed by resveratrol. Moreover, we believed that the inhibition of MMP-9/2 activation and pain sensitization may be related to the TLR-4/NF-κB signaling pathway, which might be negatively regulated by the induction of SOCS3. In conclusion, pretreatment with resveratrol could be an effective approach to alleviate trigeminal neuralgia in early stages via a powerful inhibition on the activation of MMP-9/2 in TG.
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Affiliation(s)
- Yuling Yin
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing 210029, Jiangsu Province, China; Department of Pediatric and Preventive Dentistry, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing 210029, Jiangsu Province, China
| | - Rong Guo
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing 210029, Jiangsu Province, China; Department of Pediatric and Preventive Dentistry, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing 210029, Jiangsu Province, China
| | - Yu Shao
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing 210029, Jiangsu Province, China; Department of Pediatric and Preventive Dentistry, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing 210029, Jiangsu Province, China
| | - Mixue Ge
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing 210029, Jiangsu Province, China; Department of Pediatric and Preventive Dentistry, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing 210029, Jiangsu Province, China
| | - Chen Miao
- Department of Pathology, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, 210029, Jiangsu Province, China
| | - Ling Cao
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing 210029, Jiangsu Province, China; Department of Pediatric and Preventive Dentistry, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing 210029, Jiangsu Province, China
| | - Yanjing Yang
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing 210029, Jiangsu Province, China; Department of Pediatric and Preventive Dentistry, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing 210029, Jiangsu Province, China.
| | - Liang Hu
- Neuroprotective Drug Discovery Key Laboratory of Nanjing Medical University, Department of Pharmacology, Nanjing Medical University, Nanjing 210029, Jiangsu Province, China.
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Terayama R, Tabata M, Maruhama K, Iida S. A 3 adenosine receptor agonist attenuates neuropathic pain by suppressing activation of microglia and convergence of nociceptive inputs in the spinal dorsal horn. Exp Brain Res 2018; 236:3203-3213. [PMID: 30206669 DOI: 10.1007/s00221-018-5377-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Accepted: 09/06/2018] [Indexed: 01/23/2023]
Abstract
Peripheral nerve injuries cause glial activation and neuronal hyperactivity in the spinal dorsal horn. These changes have been considered to be involved in the underlying mechanisms for the development and maintenance of neuropathic pain. Using double immunofluorescence labeling, we previously demonstrated that spinal microglial activation induced by nerve injury enhanced convergence of nociceptive inputs in the spinal dorsal horn from uninjured afferents. The adenosine A3 receptor (A3AR) agonists have been shown to have antinociceptive activities in several experimental neuropathic pain models. However, the mechanisms underlying these antinociceptive actions of the A3AR agonist are still not fully explored. In this study, the effects of the A3AR agonist (i.e., IB-MECA) on microglial activation, enhancement of convergent nociceptive inputs, and nocifensive behaviors were examined after tibial nerve injury. Injury to the tibial nerve initially caused hyposensitivity to touch stimulus at 3 days, and then resulted in tactile allodynia at 14-day post-injury. The daily systemic administration of IB-MECA (0.1 mg/kg/day) for 8 days in a row starting on the day of nerve injury or 7 days after nerve injury prevented the development of behaviorally assessed hypersensitivities, and spinal microglial activation induced by nerve injury. These treatments also suppressed anomalous convergence of nociceptive primary inputs in the spinal dorsal horn. The present findings indicate that the A3AR agonist attenuates neuropathic pain states by suppressing enhanced microglial activation, and anomalous convergence of nociceptive inputs in the spinal dorsal horn from uninjured afferents after injury to the peripheral nerve.
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Affiliation(s)
- Ryuji Terayama
- Department of Oral Function and Anatomy, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8525, Japan. .,Department of Maxillofacial Anatomy and Neuroscience, Hiroshima University Graduate School of Biomedical and Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan.
| | - Mitsuyasu Tabata
- Department of Oral Function and Anatomy, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8525, Japan.,Department of Oral and Maxillofacial Reconstructive Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8525, Japan
| | - Kotaro Maruhama
- Department of Oral Function and Anatomy, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8525, Japan
| | - Seiji Iida
- Department of Oral and Maxillofacial Reconstructive Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8525, Japan
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Jing L, Liu XD, Yang HX, Zhang M, Wang Y, Duan L, Zhang J, Lu L, Yang T, Wang DM, Chen LW, Wang MQ. ERK potentiates p38 in central sensitization induced by traumatic occlusion. Neuroscience 2016; 340:445-454. [PMID: 27865869 DOI: 10.1016/j.neuroscience.2016.11.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 10/22/2016] [Accepted: 11/08/2016] [Indexed: 12/28/2022]
Abstract
This study was to investigate the role of p38 activation via ERK1/2 phosphorylation in neurons and microglia of the spinal trigeminal subnucleus caudalis (Vc) in the promotion of orofacial hyperalgesia induced by unilateral anterior crossbite (UAC) traumatic occlusion in adult rats. U0126, a p-ERK1/2 inhibitor, was injected intracisternally before UAC implant. The effects of the U0126 injection were compared to those following the injection of SB203580, a p-p38 inhibitor. Mechanical hyperalgesia was evaluated via pressure pain threshold measurements. Brain stem tissues were processed for a Western blot analysis to evaluate the activation of ERK1/2 and p38. Double immunofluorescence was also performed to observe the expression of p-ERK1/2 and p-p38 in neurons (labeled by NeuN) and microglia (labeled by OX42). The data showed that UAC caused orofacial hyperalgia ipsilaterally on d1 to d7, peaking on d3 (P<0.05). An upregulation of p-ERK1/2 was observed in the ipsilateral Vc on d1 to d3, peaking on d1. An upregulation of p-p38 was also observed on d1 to d7, peaking on d3 (P<0.05). p-ERK1/2 primarily co-localized with NeuN and, to a lesser extent, with OX42, while p-p38 co-localized with both NeuN and OX42. Pretreatment with U0126 prevented the upregulation of both p-ERK1/2 and p-p38. Similarly to an intracisternal injection of SB203580, U0126 pretreatment attenuated the UAC-induced orofacial hyperalgesia. These data indicate that UAC caused orofacial hyperalgesia by inducing central sensitization via the activation of ERK1/2 and p38 in both neurons and microglia in the Vc, potentially impacting the effects of p-ERK1/2 during p38 activation.
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Affiliation(s)
- Lei Jing
- State Key Laboratory of Military Stomatology, Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, 145 Changlexi Road, Xi'an 710032, China
| | - Xiao-Dong Liu
- State Key Laboratory of Military Stomatology, Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, 145 Changlexi Road, Xi'an 710032, China
| | - Hong-Xu Yang
- State Key Laboratory of Military Stomatology, Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, 145 Changlexi Road, Xi'an 710032, China
| | - Mian Zhang
- State Key Laboratory of Military Stomatology, Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, 145 Changlexi Road, Xi'an 710032, China
| | - Ying Wang
- State Key Laboratory of Military Stomatology, Shaanxi Engineering Research Center for Dental Materials and Advanced Manufacture, Department of Periodontal Disease, School of Stomatology, The Fourth Military Medical University, 145 Changlexi Road, Xi'an 710032, China
| | - Li Duan
- Institute of Neurosciences, Fourth Military Medical University, 169 Changlexi Road, Xi'an 710032, China
| | - Jing Zhang
- State Key Laboratory of Military Stomatology, Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, 145 Changlexi Road, Xi'an 710032, China
| | - Lei Lu
- State Key Laboratory of Military Stomatology, Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, 145 Changlexi Road, Xi'an 710032, China
| | - Ting Yang
- State Key Laboratory of Military Stomatology, Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, 145 Changlexi Road, Xi'an 710032, China
| | - Dong-Mei Wang
- State Key Laboratory of Military Stomatology, Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, 145 Changlexi Road, Xi'an 710032, China
| | - Liang-Wei Chen
- Institute of Neurosciences, Fourth Military Medical University, 169 Changlexi Road, Xi'an 710032, China.
| | - Mei-Qing Wang
- State Key Laboratory of Military Stomatology, Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, 145 Changlexi Road, Xi'an 710032, China.
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Kaji K, Shinoda M, Honda K, Unno S, Shimizu N, Iwata K. Connexin 43 contributes to ectopic orofacial pain following inferior alveolar nerve injury. Mol Pain 2016; 12:12/0/1744806916633704. [PMID: 27030716 PMCID: PMC4955997 DOI: 10.1177/1744806916633704] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Accepted: 12/29/2015] [Indexed: 12/22/2022] Open
Abstract
Background Clinically, it is well known that injury of mandibular nerve fiber induces persistent ectopic pain which can spread to a wide area of the orofacial region innervated by the uninjured trigeminal nerve branches. However, the exact mechanism of such persistent ectopic orofacial pain is not still known. The present study was undertaken to determine the role of connexin 43 in the trigeminal ganglion on mechanical hypersensitivity in rat whisker pad skin induced by inferior alveolar nerve injury. Here, we examined changes in orofacial mechanical sensitivity following inferior alveolar nerve injury. Furthermore, changes in connexin 43 expression in the trigeminal ganglion and its localization in the trigeminal ganglion were also examined. In addition, we investigated the functional significance of connexin 43 in relation to mechanical allodynia by using a selective gap junction blocker (Gap27). Results Long-lasting mechanical allodynia in the whisker pad skin and the upper eyelid skin, and activation of satellite glial cells in the trigeminal ganglion, were induced after inferior alveolar nerve injury. Connexin 43 was expressed in the activated satellite glial cells encircling trigeminal ganglion neurons innervating the whisker pad skin, and the connexin 43 protein expression was significantly increased after inferior alveolar nerve injury. Administration of Gap27 in the trigeminal ganglion significantly reduced satellite glial cell activation and mechanical hypersensitivity in the whisker pad skin. Moreover, the marked activation of satellite glial cells encircling trigeminal ganglion neurons innervating the whisker pad skin following inferior alveolar nerve injury implies that the satellite glial cell activation exerts a major influence on the excitability of nociceptive trigeminal ganglion neurons. Conclusions These findings indicate that the propagation of satellite glial cell activation throughout the trigeminal ganglion via gap junctions, which are composed of connexin 43, plays a pivotal role in ectopic mechanical hypersensitivity in whisker pad skin following inferior alveolar nerve injury.
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Affiliation(s)
- Kaori Kaji
- Department of Orthodontics, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
| | - Masamichi Shinoda
- Department of Physiology, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
| | - Kuniya Honda
- Department of Physiology, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
| | - Syumpei Unno
- Department of Physiology, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
| | - Noriyoshi Shimizu
- Department of Orthodontics, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
| | - Koichi Iwata
- Department of Physiology, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
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Fan LY, Wang ZC, Wang P, Lan YY, Tu L. Exogenous nerve growth factor protects the hypoglossal nerve against crush injury. Neural Regen Res 2016; 10:1982-8. [PMID: 26889186 PMCID: PMC4730822 DOI: 10.4103/1673-5374.172316] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Studies have shown that sensory nerve damage can activate the p38 mitogen-activated protein kinase (MAPK) pathway, but whether the same type of nerve injury after exercise activates the p38MAPK pathway remains unclear. Several studies have demonstrated that nerve growth factor may play a role in the repair process after peripheral nerve injury, but there has been little research focusing on the hypoglossal nerve injury and repair. In this study, we designed and established rat models of hypoglossal nerve crush injury and gave intraperitoneal injections of exogenous nerve growth factor to rats for 14 days. p38MAPK activity in the damaged neurons was increased following hypoglossal nerve crush injury; exogenous nerve growth factor inhibited this increase in acitivity and increased the survival rate of motor neurons within the hypoglossal nucleus. Under transmission electron microscopy, we found that the injection of nerve growth factor contributed to the restoration of the morphology of hypoglossal nerve after crush injury. Our experimental findings indicate that exogenous nerve growth factor can protect damaged neurons and promote hypoglossal nerve regeneration following hypoglossal nerve crush injury.
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Affiliation(s)
- Li-Yuan Fan
- Department of Prosthodontics, Stomatological Hospital of Sichuan Medical University, Luzhou, Sichuan Province, China; Orofacial Reconstruction and Regeneration Laboratory, Sichuan Medical University, Luzhou, Sichuan Province, China
| | - Zhong-Chao Wang
- Orofacial Reconstruction and Regeneration Laboratory, Sichuan Medical University, Luzhou, Sichuan Province, China; Department of Endodontics, Stomatological Hospital of Sichuan Medical University, Luzhou, Sichuan Province, China
| | - Pin Wang
- Department of Prosthodontics, Stomatological Hospital of Sichuan Medical University, Luzhou, Sichuan Province, China; Orofacial Reconstruction and Regeneration Laboratory, Sichuan Medical University, Luzhou, Sichuan Province, China
| | - Yu-Yan Lan
- Department of Prosthodontics, Stomatological Hospital of Sichuan Medical University, Luzhou, Sichuan Province, China; Orofacial Reconstruction and Regeneration Laboratory, Sichuan Medical University, Luzhou, Sichuan Province, China
| | - Ling Tu
- Department of Anatomy and Physiology, College of Stomatology, Central South University, Changsha, Hunan Province, China
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Yamamoto Y, Terayama R, Kishimoto N, Maruhama K, Mizutani M, Iida S, Sugimoto T. Activated Microglia Contribute to Convergent Nociceptive Inputs to Spinal Dorsal Horn Neurons and the Development of Neuropathic Pain. Neurochem Res 2015; 40:1000-12. [DOI: 10.1007/s11064-015-1555-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 02/25/2015] [Accepted: 03/06/2015] [Indexed: 12/14/2022]
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12
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Endo Y, Shoji N, Shimada Y, Kasahara E, Iikubo M, Sato T, Sasano T, Ichikawa H. Prednisolone induces microglial activation in the subnucleus caudalis of the rat trigeminal sensory complex. Cell Mol Neurobiol 2014; 34:95-100. [PMID: 24077857 DOI: 10.1007/s10571-013-9990-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 09/17/2013] [Indexed: 12/20/2022]
Abstract
Prednisolone is a member of synthetic glucocorticoids which are widely used to treat chronic inflammatory diseases. In this study, neuronal degeneration and cell death, and glial reaction were investigated in the rat trigeminal ganglion (TG) and brainstem after subcutaneous injection of prednisolone for 7 days. Expression of c-Jun activating transcription factor 3 and caspase-3 was absent or infrequent in the TG, and cranial sensory and motor nuclei of saline- and prednisolone-treated animals. In these animals, distribution of calcitonin gene-related peptide-immunoreactive (-IR) neurons and nerve fibers was similar in the brainstem. In addition, the number of Iba1- and glial fibrillary acidic protein (GFAP)-IR cells with some processes in the brainstem was barely affected by prednisolone treatment. However, the treatment increased ramification of Iba1-IR processes in the subnucleus caudalis of the trigeminal sensory complex. Prednisolone scarcely influenced the morphology of GFAP-IR cells in the brainstem. Expression of p38 mitogen-activated protein kinase was very rare in the brainstem of saline- and prednisolone-treated animals. The present study suggests that microglia are activated by prednisolone in the subnucleus caudalis of the trigeminal sensory complex. The glucocorticoid may affect nociceptive transmission in the brainstem.
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Worsley MA, Allen CE, Billinton A, King AE, Boissonade FM. Chronic tooth pulp inflammation induces persistent expression of phosphorylated ERK (pERK) and phosphorylated p38 (pp38) in trigeminal subnucleus caudalis. Neuroscience 2014; 269:318-30. [PMID: 24709040 PMCID: PMC4030309 DOI: 10.1016/j.neuroscience.2014.03.056] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 03/13/2014] [Accepted: 03/27/2014] [Indexed: 12/29/2022]
Abstract
Chronic inflammation of tooth pulp activates pERK and pp38 in the trigeminal nucleus Activation is persistent and bilateral, and further increased by acute stimulation This altered signaling may be relevant in the development of chronic pulpitic pain pERK and pp38 are more sensitive markers of central change than Fos expression Sequential activation in different cell types may be linked to pain progression
Background Extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase are transiently phosphorylated (activated) in the spinal cord and trigeminal nucleus by acute noxious stimuli. Acute stimulation of dental pulp induces short-lived ERK activation in trigeminal subnucleus caudalis (Vc), and p38 inhibition attenuates short-term sensitization in Vc induced by acute pulpal stimulation. We have developed a model to study central changes following chronic inflammation of dental pulp that induces long-term sensitization. Here, we examine the effects of chronic inflammation and acute stimulation on the expression of phosphorylated ERK (pERK), phosphorylated p38 (pp38) and Fos in Vc. Results Chronic inflammation alone induced bilateral expression of pERK and pp38 in Vc, but did not induce Fos expression. Stimulation of both non-inflamed and inflamed pulps significantly increased pERK and pp38 bilaterally; expression was greatest in inflamed, stimulated animals, and was similar following 10-min and 60-min stimulation. Stimulation for 60 min, but not 10 min, induced Fos in ipsilateral Vc; Fos expression was significantly greater in inflamed, stimulated animals. pERK was present in both neurons and astrocytes; pp38 was present in neurons and other non-neuronal, non-astrocytic cell types. Conclusions This study provides the first demonstration that chronic inflammation of tooth pulp induces persistent bilateral activation of ERK and p38 within Vc, and that this activation is further increased by acute stimulation. This altered activity in intracellular signaling is likely to be linked to the sensitization that is seen in our animal model and in patients with pulpitis. Our data indicate that pERK and pp38 are more accurate markers of central change than Fos expression. In our model, localization of pERK and pp38 within specific cell types differs from that seen following acute stimulation. This may indicate specific roles for different cell types in the induction and maintenance of pulpitic and other types of pain.
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Affiliation(s)
- M A Worsley
- Unit of Oral & Maxillofacial Medicine & Surgery, School of Clinical Dentistry, University of Sheffield, Claremont Crescent, Sheffield S10 2TA, UK
| | - C E Allen
- Unit of Oral & Maxillofacial Medicine & Surgery, School of Clinical Dentistry, University of Sheffield, Claremont Crescent, Sheffield S10 2TA, UK
| | | | - A E King
- School of Biomedical Sciences, University of Leeds, UK
| | - F M Boissonade
- Unit of Oral & Maxillofacial Medicine & Surgery, School of Clinical Dentistry, University of Sheffield, Claremont Crescent, Sheffield S10 2TA, UK.
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Central sensitization and MAPKs are involved in occlusal interference-induced facial pain in rats. THE JOURNAL OF PAIN 2013; 14:793-807. [PMID: 23642433 DOI: 10.1016/j.jpain.2013.02.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 02/01/2013] [Accepted: 02/09/2013] [Indexed: 12/21/2022]
Abstract
UNLABELLED We previously developed a rat dental occlusal interference model of facial pain that was produced by bonding a crown onto the right maxillary first molar and was reflected in sustained facial hypersensitivity that was suggestive of the involvement of central sensitization mechanisms. The aim of the present study was to investigate potential central mechanisms involved in the occlusal interference-induced facial hypersensitivity. A combination of behavioral, immunohistochemical, Western blot, and electrophysiological recording procedures was used in 98 male adult Sprague Dawley rats that either received the occlusal interference or were sham-operated or naive rats. Immunohistochemically labeled astrocytes and microglia in trigeminal subnucleus caudalis (Vc) showed morphological changes indicative of astrocyte and microglial activation after the occlusal interference. Prolonged upregulation of p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) was also documented in Vc after placement of the occlusal interference and was expressed in both neurons and glial cells at time points when rats showed peak mechanical facial hypersensitivity. The intrathecal administration of the p38 MAPK inhibitor SB203580 to the medulla significantly inhibited the occlusal interference-induced hypersensitivity, and the ERK inhibitor PD98059 produced an even stronger effect. Central sensitization of functionally identified Vc nociceptive neurons following placement of the occlusal interference was also documented by extracellular electrophysiological recordings, and intrathecal administration of PD98059 could reverse the neuronal central sensitization. These novel findings suggest that central mechanisms including central sensitization of trigeminal nociceptive neurons and non-neuronal processes involving MAPKs play significant roles in the production of occlusal interference-induced facial pain. PERSPECTIVE Central mechanisms including trigeminal nociceptive neuronal sensitization, non-neuronal processes involving glial activation, and MAPKs play significant roles in occlusal interference-induced facial pain. These mechanisms may be involved in clinical manifestations of facial pain that have been reported in patients with an occlusal interference.
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Zhang ZJ, Dong YL, Lu Y, Cao S, Zhao ZQ, Gao YJ. Chemokine CCL2 and its receptor CCR2 in the medullary dorsal horn are involved in trigeminal neuropathic pain. J Neuroinflammation 2012; 9:136. [PMID: 22721162 PMCID: PMC3391989 DOI: 10.1186/1742-2094-9-136] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 06/21/2012] [Indexed: 01/08/2023] Open
Abstract
Background Neuropathic pain in the trigeminal system is frequently observed in clinic, but the mechanisms involved are largely unknown. In addition, the function of immune cells and related chemicals in the mechanism of pain has been recognized, whereas few studies have addressed the potential role of chemokines in the trigeminal system in chronic pain. The present study was undertaken to test the hypothesis that chemokine C-C motif ligand 2 (CCL2)-chemokine C-C motif receptor 2 (CCR2) signaling in the trigeminal nucleus is involved in the maintenance of trigeminal neuropathic pain. Methods The inferior alveolar nerve and mental nerve transection (IAMNT) was used to induce trigeminal neuropathic pain. The expression of ATF3, CCL2, glial fibrillary acidic protein (GFAP), and CCR2 were detected by immunofluorescence histochemical staining and western blot. The cellular localization of CCL2 and CCR2 were examined by immunofluorescence double staining. The effect of a selective CCR2 antagonist, RS504393 on pain hypersensitivity was checked by behavioral testing. Results IAMNT induced persistent (>21 days) heat hyperalgesia of the orofacial region and ATF3 expression in the mandibular division of the trigeminal ganglion. Meanwhile, CCL2 expression was increased in the medullary dorsal horn (MDH) from 3 days to 21 days after IAMNT. The induced CCL2 was colocalized with astroglial marker GFAP, but not with neuronal marker NeuN or microglial marker OX-42. Astrocytes activation was also found in the MDH and it started at 3 days, peaked at 10 days and maintained at 21 days after IAMNT. In addition, CCR2 was upregulated by IAMNT in the ipsilateral medulla and lasted for more than 21 days. CCR2 was mainly colocalized with NeuN and few cells were colocalized with GFAP. Finally, intracisternal injection of CCR2 antagonist, RS504393 (1, 10 μg) significantly attenuated IAMNT-induced heat hyperalgesia. Conclusion The data suggest that CCL2-CCR2 signaling may be involved in the maintenance of orofacial neuropathic pain via astroglial–neuronal interaction. Targeting CCL2-CCR2 signaling may be a potentially important new treatment strategy for trigeminal neuralgia.
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Affiliation(s)
- Zhi-Jun Zhang
- Institute of Nautical Medicine, Jiangsu Key laboratory of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, 226001, China
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Affiliation(s)
- Dong Kuk Ahn
- Department of Oral Physiology, Kyungpook National University School of Dentistry, Daegu, Korea
| | - Min Kyoung Park
- Department of Oral Physiology, Kyungpook National University School of Dentistry, Daegu, Korea
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