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Kubíčková L, Dubový P. Dynamics of Cellular Regulation of Fractalkine/CX3CL1 and Its Receptor CX3CR1 in the Rat Trigeminal Subnucleus Caudalis after Unilateral Infraorbital Nerve Lesion-Extended Cellular Signaling of the CX3CL1/CX3CR1 Axis in the Development of Trigeminal Neuropathic Pain. Int J Mol Sci 2024; 25:6069. [PMID: 38892268 PMCID: PMC11172820 DOI: 10.3390/ijms25116069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 05/27/2024] [Accepted: 05/28/2024] [Indexed: 06/21/2024] Open
Abstract
The cellular distribution and changes in CX3CL1/fractalkine and its receptor CX3CR1 protein levels in the trigeminal subnucleus caudalis (TSC) of rats with unilateral infraorbital nerve ligation (IONL) were investigated on postoperation days 1, 3, 7, and 14 (POD1, POD3, POD7, and POD14, respectively) and compared with those of sham-operated and naïve controls. Behavioral tests revealed a significant increase in tactile hypersensitivity bilaterally in the vibrissal pads of both sham- and IONL-operated animals from POD1 to POD7, with a trend towards normalization in sham controls at POD14. Image analysis revealed increased CX3CL1 immunofluorescence (IF) intensities bilaterally in the TSC neurons of both sham- and IONL-operated rats at all survival periods. Reactive astrocytes in the ipsilateral TSC also displayed CX3CL1-IF from POD3 to POD14. At POD1 and POD3, microglial cells showed high levels of CX3CR1-IF, which decreased by POD7 and POD14. Conversely, CX3CR1 was increased in TSC neurons and reactive astrocytes at POD7 and POD14, which coincided with high levels of CX3CL1-IF and ADAM17-IF. This indicates that CX3CL1/CX3CR1 may be involved in reciprocal signaling between TSC neurons and reactive astrocytes. The level of CatS-IF in microglial cells suggests that soluble CX3CL1 may be involved in neuron-microglial cell signaling at POD3 and POD7, while ADAM17 allows this release at all studied time points. These results indicate an extended CX3CL1/CX3CR1 signaling axis and its role in the crosstalk between TSC neurons and glial cells during the development of trigeminal neuropathic pain.
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Affiliation(s)
| | - Petr Dubový
- Cellular and Molecular Research Group, Department of Anatomy, Faculty of Medicine, Masaryk University, Kamenice 3, CZ-62500 Brno, Czech Republic;
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Chung MK, Wang S, Alshanqiti I, Hu J, Ro JY. The degeneration-pain relationship in the temporomandibular joint: Current understandings and rodent models. FRONTIERS IN PAIN RESEARCH 2023; 4:1038808. [PMID: 36846071 PMCID: PMC9947567 DOI: 10.3389/fpain.2023.1038808] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 01/18/2023] [Indexed: 02/11/2023] Open
Abstract
Temporomandibular disorders (TMD) represent a group of musculoskeletal conditions involving the temporomandibular joints (TMJ), the masticatory muscles and associated structures. Painful TMD are highly prevalent and conditions afflict 4% of US adults annually. TMD include heterogenous musculoskeletal pain conditions, such as myalgia, arthralgia, and myofascial pain. A subpopulations of TMD patients show structural changes in TMJ, including disc displacement or degenerative joint diseases (DJD). DJD is a slowly progressing, degenerative disease of the TMJ characterized by cartilage degradation and subchondral bone remodeling. Patients with DJD often develop pain (TMJ osteoarthritis; TMJ OA), but do not always have pain (TMJ osteoarthrosis). Therefore, pain symptoms are not always associated with altered TMJ structures, which suggests that a causal relationship between TMJ degeneration and pain is unclear. Multiple animal models have been developed for determining altered joint structure and pain phenotypes in response to various TMJ injuries. Rodent models of TMJOA and pain include injections to induce inflammation or cartilage destruction, sustained opening of the oral cavity, surgical resection of the articular disc, transgenic approaches to knockout or overexpress key genes, and an integrative approach with superimposed emotional stress or comorbidities. In rodents, TMJ pain and degeneration occur during partially overlapping time periods in these models, which suggests that common biological factors may mediate TMJ pain and degeneration over different time courses. While substances such as intra-articular pro-inflammatory cytokines commonly cause pain and joint degeneration, it remains unclear whether pain or nociceptive activities are causally associated with structural degeneration of TMJ and whether structural degeneration of TMJ is necessary for producing persistent pain. A thorough understanding of the determining factors of pain-structure relationships of TMJ during the onset, progression, and chronification by adopting novel approaches and models should improve the ability to simultaneously treat TMJ pain and TMJ degeneration.
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Affiliation(s)
- Man-Kyo Chung
- Department of Neural and Pain Sciences, School of Dentistry, Program in Neuroscience, Center to Advance Chronic Pain Research, University of Maryland Baltimore, Baltimore, MD, United States
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Liu YJ, Li YL, Fang ZH, Liao HL, Zhang YY, Lin J, Liu F, Shen JF. NMDARs mediate peripheral and central sensitization contributing to chronic orofacial pain. Front Cell Neurosci 2022; 16:999509. [PMID: 36238833 PMCID: PMC9553029 DOI: 10.3389/fncel.2022.999509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 08/22/2022] [Indexed: 11/28/2022] Open
Abstract
Peripheral and central sensitizations of the trigeminal nervous system are the main mechanisms to promote the development and maintenance of chronic orofacial pain characterized by allodynia, hyperalgesia, and ectopic pain after trigeminal nerve injury or inflammation. Although the pathomechanisms of chronic orofacial pain are complex and not well known, sufficient clinical and preclinical evidence supports the contribution of the N-methyl-D-aspartate receptors (NMDARs, a subclass of ionotropic glutamate receptors) to the trigeminal nociceptive signal processing pathway under various pathological conditions. NMDARs not only have been implicated as a potential mediator of pain-related neuroplasticity in the peripheral nervous system (PNS) but also mediate excitatory synaptic transmission and synaptic plasticity in the central nervous system (CNS). In this review, we focus on the pivotal roles and mechanisms of NMDARs in the trigeminal nervous system under orofacial neuropathic and inflammatory pain. In particular, we summarize the types, components, and distribution of NMDARs in the trigeminal nervous system. Besides, we discuss the regulatory roles of neuron-nonneuronal cell/neuron-neuron communication mediated by NMDARs in the peripheral mechanisms of chronic orofacial pain following neuropathic injury and inflammation. Furthermore, we review the functional roles and mechanisms of NMDARs in the ascending and descending circuits under orofacial neuropathic and inflammatory pain conditions, which contribute to the central sensitization. These findings are not only relevant to understanding the underlying mechanisms, but also shed new light on the targeted therapy of chronic orofacial pain.
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Affiliation(s)
- Ya-Jing Liu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, National Center for Stomatology, West China School of Stomatology, Sichuan University, Chengdu, China
- Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yue-Ling Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, National Center for Stomatology, West China School of Stomatology, Sichuan University, Chengdu, China
- Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Zhong-Han Fang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, National Center for Stomatology, West China School of Stomatology, Sichuan University, Chengdu, China
- Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Hong-Lin Liao
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, National Center for Stomatology, West China School of Stomatology, Sichuan University, Chengdu, China
- Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yan-Yan Zhang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, National Center for Stomatology, West China School of Stomatology, Sichuan University, Chengdu, China
- Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jiu Lin
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, National Center for Stomatology, West China School of Stomatology, Sichuan University, Chengdu, China
- Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Fei Liu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, National Center for Stomatology, West China School of Stomatology, Sichuan University, Chengdu, China
- Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- *Correspondence: Jie-Fei Shen Fei Liu
| | - Jie-Fei Shen
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, National Center for Stomatology, West China School of Stomatology, Sichuan University, Chengdu, China
- Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- *Correspondence: Jie-Fei Shen Fei Liu
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Okamoto K, Hasegawa M, Piriyaprasath K, Kakihara Y, Saeki M, Yamamura K. Preclinical models of deep craniofacial nociception and temporomandibular disorder pain. JAPANESE DENTAL SCIENCE REVIEW 2021; 57:231-241. [PMID: 34815817 PMCID: PMC8593658 DOI: 10.1016/j.jdsr.2021.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 10/15/2021] [Accepted: 10/19/2021] [Indexed: 01/06/2023] Open
Abstract
Chronic pain in temporomandibular disorder (TMD) is a common health problem. Cumulating evidence indicates that the etiology of TMD pain is complex with multifactorial experience that could hamper the developments of treatments. Preclinical research is a resource to understand the mechanism for TMD pain, whereas limitations are present as a disease-specific model. It is difficult to incorporate multiple risk factors associated with the etiology that could increase pain responses into a single animal. This article introduces several rodent models which are often employed in the preclinical studies and discusses their validities for TMD pain after the elucidations of the neural mechanisms based on the clinical reports. First, rodent models were classified into two groups with or without inflammation in the deep craniofacial tissues. Next, the characteristics of each model and the procedures to identify deep craniofacial pain were discussed. Emphasis was directed on the findings of the effects of chronic psychological stress, a major risk factor for chronic pain, on the deep craniofacial nociception. Preclinical models have provided clinically relevant information, which could contribute to better understand the basis for TMD pain, while efforts are still required to bridge the gap between animal and human studies.
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Affiliation(s)
- Keiichiro Okamoto
- Division of Oral Physiology, Niigata University Graduate School of Medical and Dental Sciences, 2-5274, Gakkocho-dori, Chuo-ku, Niigata City, 951-8514, Japan
| | - Mana Hasegawa
- Division of Oral Physiology, Niigata University Graduate School of Medical and Dental Sciences, 2-5274, Gakkocho-dori, Chuo-ku, Niigata City, 951-8514, Japan.,Division of Dental Clinical Education, Niigata University Graduate School of Medical and Dental Sciences, 2-5274, Gakkocho-dori, Chuo-ku, Niigata City, 951-8514, Japan
| | - Kajita Piriyaprasath
- Division of Oral Physiology, Niigata University Graduate School of Medical and Dental Sciences, 2-5274, Gakkocho-dori, Chuo-ku, Niigata City, 951-8514, Japan
| | - Yoshito Kakihara
- Division of Dental Pharmacology, Niigata University Graduate School of Medical and Dental Sciences, 2-5274, Gakkocho-dori, Chuo-ku, Niigata City, 951-8514, Japan
| | - Makio Saeki
- Division of Dental Pharmacology, Niigata University Graduate School of Medical and Dental Sciences, 2-5274, Gakkocho-dori, Chuo-ku, Niigata City, 951-8514, Japan
| | - Kensuke Yamamura
- Division of Oral Physiology, Niigata University Graduate School of Medical and Dental Sciences, 2-5274, Gakkocho-dori, Chuo-ku, Niigata City, 951-8514, Japan
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Solis-Castro OO, Wong N, Boissonade FM. Chemokines and Pain in the Trigeminal System. FRONTIERS IN PAIN RESEARCH 2021; 2:689314. [PMID: 35295531 PMCID: PMC8915704 DOI: 10.3389/fpain.2021.689314] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 06/11/2021] [Indexed: 11/13/2022] Open
Abstract
Chemotactic cytokines or chemokines are a large family of secreted proteins able to induce chemotaxis. Chemokines are categorized according to their primary amino acid sequence, and in particular their cysteine residues that form disulphide bonds to maintain the structure: CC, CXC, CX3C, and XC, in which X represents variable amino acids. Among their many roles, chemokines are known to be key players in pain modulation in the peripheral and central nervous systems. Thus, they are promising candidates for novel therapeutics that could replace current, often ineffective treatments. The spinal and trigeminal systems are intrinsically different beyond their anatomical location, and it has been suggested that there are also differences in their sensory mechanisms. Hence, understanding the different mechanisms involved in pain modulation for each system could aid in developing appropriate pharmacological alternatives. Here, we aim to describe the current landscape of chemokines that have been studied specifically with regard to trigeminal pain. Searching PubMed and Google Scholar, we identified 30 reports describing chemokines in animal models of trigeminal pain, and 15 reports describing chemokines involved in human pain associated with the trigeminal system. This review highlights the chemokines studied to date at different levels of the trigeminal system, their cellular localization and, where available, their role in a variety of animal pain models.
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Affiliation(s)
- Oscar O. Solis-Castro
- School of Clinical Dentistry, University of Sheffield, Sheffield, United Kingdom
- The Neuroscience Institute, University of Sheffield, Sheffield, United Kingdom
| | - Natalie Wong
- School of Clinical Dentistry, University of Sheffield, Sheffield, United Kingdom
- The Neuroscience Institute, University of Sheffield, Sheffield, United Kingdom
| | - Fiona M. Boissonade
- School of Clinical Dentistry, University of Sheffield, Sheffield, United Kingdom
- The Neuroscience Institute, University of Sheffield, Sheffield, United Kingdom
- *Correspondence: Fiona M. Boissonade
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Glia and Orofacial Pain: Progress and Future Directions. Int J Mol Sci 2021; 22:ijms22105345. [PMID: 34069553 PMCID: PMC8160907 DOI: 10.3390/ijms22105345] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 12/14/2022] Open
Abstract
Orofacial pain is a universal predicament, afflicting millions of individuals worldwide. Research on the molecular mechanisms of orofacial pain has predominately focused on the role of neurons underlying nociception. However, aside from neural mechanisms, non-neuronal cells, such as Schwann cells and satellite ganglion cells in the peripheral nervous system, and microglia and astrocytes in the central nervous system, are important players in both peripheral and central processing of pain in the orofacial region. This review highlights recent molecular and cellular findings of the glia involvement and glia–neuron interactions in four common orofacial pain conditions such as headache, dental pulp injury, temporomandibular joint dysfunction/inflammation, and head and neck cancer. We will discuss the remaining questions and future directions on glial involvement in these four orofacial pain conditions.
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Nicot R, Barry F, Chijcheapaza-Flores H, Garcia-Fernandez MJ, Raoul G, Blanchemain N, Chai F. A Systematic Review of Rat Models With Temporomandibular Osteoarthritis Suitable for the Study of Emerging Prolonged Intra-Articular Drug Delivery Systems. J Oral Maxillofac Surg 2021; 79:1650-1671. [PMID: 33775650 DOI: 10.1016/j.joms.2021.02.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 02/20/2021] [Accepted: 02/22/2021] [Indexed: 11/29/2022]
Abstract
PURPOSE Development of minimally invasive therapies for temporomandibular joint osteoarthritis (TMJOA) has focused on drug intra-articular injections to avoid the systemic adverse effects experienced when these substances are administered orally. Therefore, we performed a systematic review to answer the question "Which method of induction of a TMJOA-related pain model in rats leads to prolonged painful symptoms, allowing the best assessment of a sustained drug delivery system?" MATERIALS AND METHODS Following the PRISMA guidelines, we searched MEDLINE for papers published from 1994 to July 2020 on a TMJ arthritis model using rats. We identified the means of pain induction and of nociception assessment. We assessed protocol bias using an adaptation of the QUADAS-2 tool. Animal selection, the reference standard method of pain assessment, applicability of a statistical assessment, and flow and timing were assessed. RESULTS Of the 59 full papers we reviewed, 41 performed no pain assessment after the first 7 days following induction of the TMJ-related pain model. We eventually identified 18 long-term TMJOA-related pain models. Pain was induced by injection of toxic substances, most commonly Freund's complete adjuvant (50 μg per 50 μl), formalin at various concentrations, or monosodium iodoacetate (0,5 mg per 50 μl), into the TMJ, or by physical methods. Few studies reported data on pain after 21 days of follow-up. Heterogeneity of induction methods, pain assessment methods, and flow and timing biases precluded a meta-analysis. CONCLUSIONS Given that pain is 1 of the main symptoms of TMJOA, experimental study protocols should include long-term pain assessment.
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Affiliation(s)
- Romain Nicot
- Associate Professor, Univ. Lille, CHU Lille, INSERM, Service de Chirurgie Maxillo-Faciale et Stomatologie, U1008 - Controlled Drug Delivery Systems and Biomaterials, Lille, France.
| | - Florent Barry
- Resident, Univ. Lille, CHU Lille, INSERM, Service de Chirurgie Maxillo-Faciale et Stomatologie, U1008 - Controlled Drug Delivery Systems and Biomaterials, Lille, France
| | - Henry Chijcheapaza-Flores
- Research Assistant, Univ. Lille, INSERM, CHU Lille, U1008 - Controlled Drug Delivery Systems and Biomaterials, Lille, France
| | - Maria José Garcia-Fernandez
- Associate Professor, Univ. Lille, INSERM, CHU Lille, U1008 - Controlled Drug Delivery Systems and Biomaterials, Lille, France
| | - Gwénaël Raoul
- Professor, Univ. Lille, CHU Lille, INSERM, Service de Chirurgie Maxillo-Faciale et Stomatologie, U1008 - Controlled Drug Delivery Systems and Biomaterials, Lille, France
| | - Nicolas Blanchemain
- Professor, Department Head, Univ. Lille, INSERM, CHU Lille, U1008 - Controlled Drug Delivery Systems and Biomaterials, Lille, France
| | - Feng Chai
- Research engineer, Univ. Lille, INSERM, CHU Lille, U1008 - Controlled Drug Delivery Systems and Biomaterials, Lille, France
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Liang L, Tao YX. Expression of acetyl-histone H3 and acetyl-histone H4 in dorsal root ganglion and spinal dorsal horn in rat chronic pain models. Life Sci 2018; 211:182-188. [PMID: 30236868 DOI: 10.1016/j.lfs.2018.09.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 09/07/2018] [Accepted: 09/16/2018] [Indexed: 02/07/2023]
Abstract
AIMS Histone acetylation and deacetylation are two histone posttranslational modifications that are usually controlled by histone acetyltransferases (HATs) and histone deacetylases (HDACs). Although HATs or HDACs Inhibitors could relieve pain hypersensitivities in chronic pain animal models, it is not clear on the expression of global histone acetylation in the dorsal root ganglion (DRG) or spinal dorsal horn in chronic pain conditions. MAIN METHODS A spinal nerve ligation (SNL)-induced neuropathic pain model and a complete Freund's adjuvant (CFA)-induced inflammatory pain model in rats were used to examine the expression of total acetyl-histone H3 (AcH3) and total acetyl-histone H4 (AcH4) by immunofluorescence or western blot. KEY FINDINGS AcH3 and AcH4 not only localized in neuronal nuclei, but also in nuclei of glial cells in the DRG. Unilateral SNL induced the increase of AcH3 and AcH4 expression in the injured lumbar 5 (L5) DRG, but not in the uninjured L5 DRG or the spinal dorsal horn, while unilateral intraplantar injection of CFA increased AcH3 and AcH4 expression in the ipsilateral L4/5 spinal dorsal horn, but not in the L4/5 DRG. SIGNIFICANCE These results provide morphological evidence for global histone acetylation expression in the DRG and spinal cord and indicate the differential expression in the DRG and spinal dorsal horn in different chronic pain models. More precise epigenetic mechanisms of histone acetylation on the target genes need to be revealed.
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Affiliation(s)
- Lingli Liang
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA; Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, PR China; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Beijing, PR China.
| | - Yuan-Xiang Tao
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA; Department of Cell Biology & Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA; Department of Physiology, Pharmacology & Neuroscience, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
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Micronized palmitoylethanolamide reduces joint pain and glial cell activation. Inflamm Res 2018; 67:891-901. [PMID: 30121836 DOI: 10.1007/s00011-018-1179-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 08/03/2018] [Accepted: 08/08/2018] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVE AND DESIGN Temporomandibular disorder (TMD) is a common painful condition in the temporomandibular joint (TMJ). Joint inflammation is believed to be a chief cause of pain in patients with TMD, through the release of pro-inflammatory cytokines that induce peripheral sensitization of nerve terminals followed by microglial stimulation. MATERIALS AND SUBJECT TMJ was induced in rats with the injection of complete Freund's adjuvant (CFA) emulsion into the left TMJ capsule. TREATMENT The present study would assess the effects of micronized palmitoylethanolamide (m-PEA) on glial activation and trigeminal hypersensitivity. METHODS Ten mg/kg m-PEA or corresponding vehicle was administered 1 h after CFA and mechanical allodynia and edema were evaluated at 24 and 72 h after CFA injection. RESULTS CFA-injected animals showed TMJ edema and ipsilateral mechanical allodynia accompanied by a robust growth in GFAP protein-positive satellite glial cells and activation of resident macrophages in the TG. Moreover, m-PEA administration significantly reduced the degree of TMJ damage and pain, macrophage activation in TG and up-regulation of Iba1. CONCLUSIONS The results confirm that m-PEA could represent a novel approach for monitoring pain during trigeminal nerve sensitization.
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Activation of corticotropin-releasing factor neurons and microglia in paraventricular nucleus precipitates visceral hypersensitivity induced by colorectal distension in rats. Brain Behav Immun 2016; 55:93-104. [PMID: 26743854 DOI: 10.1016/j.bbi.2015.12.022] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 12/23/2015] [Accepted: 12/28/2015] [Indexed: 02/08/2023] Open
Abstract
Visceral hypersensitivity is a major contributor to irritable bowel syndrome and other disorders with visceral pain. Substantial evidence has established that glial activation and neuro-glial interaction play a key role in the establishment and maintenance of visceral hypersensitivity. We recently demonstrated that activation of spinal microglial toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88)/nuclear factor κB (NF-κB) signaling facilitated the development of visceral hypersensitivity in a rat model developed by neonatal and adult colorectal distensions (CRDs). Hypothalamic paraventricular nucleus (PVN) plays a pivotal role in the pathogenesis of chronic pain. In this study, we examined the mechanism by which microglia and neurons in PVN establish and maintain visceral hypersensitivity and the involvement of TLR4 signaling. Visceral hypersensitivity was precipitated by adult colorectal distension (CRD) only in rats that experienced neonatal CRDs. Visceral hypersensitivity was associated with an increase in the expression of c-fos, corticotropin-releasing factor (CRF) protein and mRNA in PVN, which could be prevented by intra-PVN infusion of lidocaine or small interfering RNA targeting the CRF gene. These results suggest PVN CRF neurons modulate visceral hypersensitivity. Adult CRD induced an increase in the expression of Iba-1 (a microglial marker), TLR4 protein, and its downstream effectors MyD88, NF-κB, as well as proinflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) only in rats that experienced neonatal CRDs. Intra-PVN infusion of minocycline, a nonselective microglial inhibitor, attenuated the hyperactivity of TLR4 signaling cascade, microglial activation, and visceral hypersensitivity. Taken together, these data suggest that neonatal CRDs induce a glial activation in PVN. Adult CRD potentiates the glial and CRF neuronal activity, and precipitates visceral hypersensitivity and pain. TLR4 signaling and proinflammatory cytokines TNF-α and IL-1β may participate in neuro-glial interaction during the pathogenesis of visceral hypersensitivity.
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Moon JY, Roh DH, Yoon SY, Choi SR, Kwon SG, Choi HS, Kang SY, Han HJ, Beitz AJ, Oh SB, Lee JH. σ1 receptors activate astrocytes via p38 MAPK phosphorylation leading to the development of mechanical allodynia in a mouse model of neuropathic pain. Br J Pharmacol 2014; 171:5881-97. [PMID: 25158784 PMCID: PMC4290724 DOI: 10.1111/bph.12893] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 08/12/2014] [Accepted: 08/21/2014] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND AND PURPOSE Spinal astrocytes have emerged as important mechanistic contributors to the genesis of mechanical allodynia (MA) in neuropathic pain. We recently demonstrated that the spinal sigma non-opioid intracellular receptor 1 (σ1 receptor) modulates p38 MAPK phosphorylation (p-p38), which plays a critical role in the induction of MA in neuropathic rats. However, the histological and physiological relationships among σ1, p-p38 and astrocyte activation is unclear. EXPERIMENTAL APPROACH We investigated: (i) the precise location of σ1 receptors and p-p38 in spinal dorsal horn; (ii) whether the inhibition of σ1 receptors or p38 modulates chronic constriction injury (CCI)-induced astrocyte activation; and (iii) whether this modulation of astrocyte activity is associated with MA development in CCI mice. KEY RESULTS The expression of σ1 receptors was significantly increased in astrocytes on day 3 following CCI surgery. Sustained intrathecal treatment with the σ1 antagonist, BD-1047, attenuated CCI-induced increase in GFAP-immunoreactive astrocytes, and the treatment combined with fluorocitrate, an astrocyte metabolic inhibitor, synergistically reduced the development of MA, but not thermal hyperalgesia. The number of p-p38-ir astrocytes and neurons, but not microglia was significantly increased. Interestingly, intrathecal BD-1047 attenuated the expression of p-p38 selectively in astrocytes but not in neurons. Moreover, intrathecal treatment with a p38 inhibitor attenuated the GFAP expression, and this treatment combined with fluorocitrate synergistically blocked the induction of MA. CONCLUSIONS AND IMPLICATIONS Spinal σ1 receptors are localized in astrocytes and blockade of σ1 receptors inhibits the pathological activation of astrocytes via modulation of p-p38, which ultimately prevents the development of MA in neuropathic mice.
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Affiliation(s)
- J Y Moon
- Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National UniversitySeoul, Korea
| | - D H Roh
- Department of Maxillofacial Tissue Regeneration, Kyung Hee University School of DentistrySeoul, Korea
| | - S Y Yoon
- Laboratory of Molecular Signal Transduction, Center for Neural Science, Korea Institute of Science and Technology (KIST)Seoul, Korea
| | - S R Choi
- Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National UniversitySeoul, Korea
| | - S G Kwon
- Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National UniversitySeoul, Korea
| | - H S Choi
- Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National UniversitySeoul, Korea
| | - S Y Kang
- Acupuncture, Moxibustion and Meridian Research Group, Medical Research Division, Korea Institute of Oriental MedicineDaejeon, Korea
| | - H J Han
- Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National UniversitySeoul, Korea
| | - A J Beitz
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of MinnesotaSt Paul, MN, USA
| | - S B Oh
- Pain Cognitive Function Research Center, Department of Brain and Cognitive Sciences College of Natural Sciences, Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National UniversitySeoul, Korea
| | - J H Lee
- Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National UniversitySeoul, Korea
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Di Cesare Mannelli L, Pacini A, Micheli L, Tani A, Zanardelli M, Ghelardini C. Glial role in oxaliplatin-induced neuropathic pain. Exp Neurol 2014; 261:22-33. [PMID: 24967684 DOI: 10.1016/j.expneurol.2014.06.016] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 06/13/2014] [Accepted: 06/17/2014] [Indexed: 12/13/2022]
Abstract
Oxaliplatin, a platinum-based chemotherapeutic agent, has become a standard treatment for advanced colorectal cancer. The dose-limiting toxicity of this compound is the development of peripheral neuropathy. A tangled panel of symptoms, sensory loss, paresthesia, dysesthesia and pain, may be disabling for patients and adversely affect their quality of life. Recently, we described a characteristic glial activation profile in a rat model of oxaliplatin-induced neuropathy. Glial cells are considered a new pharmacological target for neuropathic pain relief but its relevance in chemotherapy-dependent neuropathies is debated. Aimed to evaluate the significance of glial activation in pain generated by oxaliplatin, the microglial inhibitor minocycline or the astrocyte inhibitor fluorocitrate were continuously infused by intrathecal route in oxaliplatin-treated rats. Both compounds significantly reduced oxaliplatin-evoked pain though the efficacy of fluorocitrate was higher revealing a prominent role of astrocytes. Immunohistochemical analysis of the dorsal horn confirmed the specific Iba1-positive cell inhibition caused by minocycline as well as the selectivity of fluorocitrate on GFAP-positive cells. The activation of astrocytes in minocycline-treated rats suggests a microglia-independent modulation of astrocytes by oxaliplatin neurotoxicity. Neither the selective activation of astrocyte after minocycline treatment nor the exclusive microglial response after fluorocitrate is able to evoke pain. Morphometric and morphological determinations performed on dorsal root ganglia evidenced that the glial inhibitors did not prevent the oxaliplatin-dependent increase of eccentric nucleoli and multinucleolated neurons. The decrease of soma area was also unaltered. In summary, these data highlight the role of central glial cells in oxaliplatin-dependent neuropathic pain. On the other hand, glial inhibition is not associated with neuroprotective effects suggesting the need for careful modulation of glial signaling to prevent the pathophysiology that leads to persistent neuropathic pain.
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Affiliation(s)
- Lorenzo Di Cesare Mannelli
- Dept. of Neuroscience, Psychology, Drug Research and Child Health - NEUROFARBA, Pharmacology and Toxicology Section, University of Florence, Florence, Italy.
| | - Alessandra Pacini
- Dept. of Experimental and Clinical Medicine - DMSC, Anatomy and Histology Section, University of Florence, Florence, Italy
| | - Laura Micheli
- Dept. of Neuroscience, Psychology, Drug Research and Child Health - NEUROFARBA, Pharmacology and Toxicology Section, University of Florence, Florence, Italy
| | - Alessia Tani
- Dept. of Experimental and Clinical Medicine - DMSC, Anatomy and Histology Section, University of Florence, Florence, Italy
| | - Matteo Zanardelli
- Dept. of Neuroscience, Psychology, Drug Research and Child Health - NEUROFARBA, Pharmacology and Toxicology Section, University of Florence, Florence, Italy
| | - Carla Ghelardini
- Dept. of Neuroscience, Psychology, Drug Research and Child Health - NEUROFARBA, Pharmacology and Toxicology Section, University of Florence, Florence, Italy
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Li B, Lu L, Tan X, Zhong M, Guo Y, Yi X. Peripheral metabotropic glutamate receptor subtype 5 contributes to inflammation-induced hypersensitivity of the rat temporomandibular joint. J Mol Neurosci 2013; 51:710-8. [PMID: 23807708 DOI: 10.1007/s12031-013-0052-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 06/13/2013] [Indexed: 01/15/2023]
Abstract
Temporomandibular disorders (TMD) comprise an assortment of clinical conditions characterized by pain in the temporomandibular joint (TMJ). TMD patients have a variety of symptoms, including jaw movement disorder and TMJ pain. Metabotropic glutamate receptor subtype 5 (mGluR5) was reported to be involved in pain processing in several animal models of neuropathic and inflammatory pain. In this study, the head withdrawal threshold and mGluR5 expression were investigated in rats with complete Freund's adjuvant (CFA)-induced TMJ inflammatory pain. CFA injection into the TMJ significantly decreased the mechanical head withdrawal thresholds relative to vehicle injection, and the effects were blocked by pre-injection of 2-methyl-6-(phenylethynyl)-pyridine (MPEP). mGluR5 expression in the trigeminal ganglion was predominantly increased in the CFA-injected group compared with the normal control group. Pretreatment with MPEP, a selective mGluR5 antagonist, reduced mGluR5 expression in the trigeminal ganglion compared with the CFA group, as measured by immunohistochemistry, western blotting, and RT-PCR. Significant differences in the proportion or intensity of mGluR5 expression were found in animals with inflammation versus control animals at the examined time point. These findings indicate a role for peripheral mGluR5 in CFA-induced nociceptive behavior and TMJ inflammation. Peripheral application of mGluR5 antagonists could provide therapeutic benefits for inflammatory TMJ pain.
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Affiliation(s)
- Bo Li
- Department of Oral Anatomy and Physiology, School of Stomatology, China Medical University, Shenyang, Liaoning, 110002, China
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