1
|
Xue Y, Mo S, Li Y, Cao Y, Xu X, Xie Q. Dissecting neural circuits from rostral ventromedial medulla to spinal trigeminal nucleus bidirectionally modulating craniofacial mechanical sensitivity. Prog Neurobiol 2024; 232:102561. [PMID: 38142769 DOI: 10.1016/j.pneurobio.2023.102561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 11/24/2023] [Accepted: 12/15/2023] [Indexed: 12/26/2023]
Abstract
Chronic craniofacial pain is intractable and its mechanisms remain unclarified. The rostral ventromedial medulla (RVM) plays a crucial role in descending pain facilitation and inhibition. It is unclear how the descending circuits from the RVM to spinal trigeminal nucleus (Sp5) are organized to bidirectionally modulate craniofacial nociception. We used viral tracing, in vivo optogenetics, calcium signaling recording, and chemogenetic manipulations to investigate the structure and function of RVM-Sp5 circuits. We found that most RVM neurons projecting to Sp5 were GABAergic or glutamatergic and facilitated or inhibited craniofacial nociception, respectively. Both GABAergic interneurons and glutamatergic projection neurons in Sp5 received RVM inputs: the former were antinociceptive, whereas the latter were pronociceptive. Furthermore, we demonstrated activation of both GABAergic and glutamatergic Sp5 neurons receiving RVM inputs in inflammation- or dysfunction-induced masseter hyperalgesia. Activating GABAergic Sp5 neurons or inhibiting glutamatergic Sp5 neurons that receive RVM projections reversed masseter hyperalgesia. Our study identifies specific cell types and projections of RVM-Sp5 circuits involved in facilitating or inhibiting craniofacial nociception respectively. Selective manipulation of RVM-Sp5 circuits can be used as potential treatment strategy to relieve chronic craniofacial muscle pain.
Collapse
Affiliation(s)
- Yang Xue
- Department of Prosthodontics, Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, PR China
| | - Siyi Mo
- Department of Prosthodontics, Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, PR China
| | - Yuan Li
- Department of Prosthodontics, Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, PR China
| | - Ye Cao
- Department of Prosthodontics, Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, PR China.
| | - Xiaoxiang Xu
- Department of Prosthodontics, Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, PR China.
| | - Qiufei Xie
- Department of Prosthodontics, Center for Oral and Jaw Functional Diagnosis, Treatment and Research, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, PR China.
| |
Collapse
|
2
|
Zhang Y, Mao R, Liu Z, Shi M, Song D, Liu X, Yan D, Bao J, Tang Y. Efficacy and safety of NAHAO® hydrogel in amelioration of chemoradiotherapy-induced oral mucositis: An preliminary clinical study (ChiCTR2200064766). JOURNAL OF STOMATOLOGY, ORAL AND MAXILLOFACIAL SURGERY 2023; 124:101568. [PMID: 37524129 DOI: 10.1016/j.jormas.2023.101568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 07/10/2023] [Accepted: 07/18/2023] [Indexed: 08/02/2023]
Abstract
OBJECTIVE To evaluate the efficacy of NAHAO® oral mucosal antibacterial care solution (NAHAO® spray) on attenuating oral mucositis (OM) symptoms and related mechanisms investigation. MATERIAL AND METHODS Experimental OM models were established by acetic acid and 5-fluorouracil combined with mechanical trauma. We investigated spontaneous pain of conscious OM rats after using NAHAO®. The expression of NF-κB in affected trigeminal ganglion was measured by western blot. In clinical study, 60 patients who developed post-treatment OM of grade 2 or above or persistent mucosal pain with a score equal to or greater than 4 points were selected. All patients were required to receive NAHAO® spray 8 times a day and were examined for OM degrees and oral mucosal pain scores before and after application. RESULTS Experimental data from experimental model suggested that clinical efficacy of NAHAO® spray was involved in inflammation inhibition via NF-κB pathway. The results of clinical study showed that NAHAO® spray improved the symptoms of OM, there is statistically significant difference in oral mucosal pain scores after treated with NAHAO, and the dietary restrictions were also improved. CONCLUSION NAHAO® spray alleviates pain and improves the diet situation in OM patients, which is partly mediated through the inhibition of NF-κB pathway.
Collapse
Affiliation(s)
- Yujiao Zhang
- School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu 211198, China
| | - Rui Mao
- School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu 211198, China
| | - Zhixian Liu
- Department of Pharmacy, Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, Jiangsu 210009, China
| | - Meiqi Shi
- Department of Medical Oncology, Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, Jiangsu 210009, China
| | - Dan Song
- Department of Radiotherapy, Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, Jiangsu 210009, China
| | - Xiaolin Liu
- Department of Pharmacy, Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, Jiangsu 210009, China
| | - Dan Yan
- Department of Pharmacy, Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, Jiangsu 210009, China
| | - Jun Bao
- Department of Medical Oncology, Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, Jiangsu 210009, China
| | - Yiqun Tang
- School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu 211198, China.
| |
Collapse
|
3
|
Sadighparvar S, Al-Hamed FS, Sharif-Naeini R, Meloto CB. Preclinical orofacial pain assays and measures and chronic primary orofacial pain research: where we are and where we need to go. FRONTIERS IN PAIN RESEARCH 2023; 4:1150749. [PMID: 37293433 PMCID: PMC10244561 DOI: 10.3389/fpain.2023.1150749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 04/11/2023] [Indexed: 06/10/2023] Open
Abstract
Chronic primary orofacial pain (OFP) conditions such as painful temporomandibular disorders (pTMDs; i.e., myofascial pain and arthralgia), idiopathic trigeminal neuralgia (TN), and burning mouth syndrome (BMS) are seemingly idiopathic, but evidence support complex and multifactorial etiology and pathophysiology. Important fragments of this complex array of factors have been identified over the years largely with the help of preclinical studies. However, findings have yet to translate into better pain care for chronic OFP patients. The need to develop preclinical assays that better simulate the etiology, pathophysiology, and clinical symptoms of OFP patients and to assess OFP measures consistent with their clinical symptoms is a challenge that needs to be overcome to support this translation process. In this review, we describe rodent assays and OFP pain measures that can be used in support of chronic primary OFP research, in specific pTMDs, TN, and BMS. We discuss their suitability and limitations considering the current knowledge of the etiology and pathophysiology of these conditions and suggest possible future directions. Our goal is to foster the development of innovative animal models with greater translatability and potential to lead to better care for patients living with chronic primary OFP.
Collapse
Affiliation(s)
- Shirin Sadighparvar
- Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
- The Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
| | | | - Reza Sharif-Naeini
- The Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
- Department of Physiology and Cell Information Systems, McGill University, Montreal, QC, Canada
| | - Carolina Beraldo Meloto
- The Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
- Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, QC, Canada
| |
Collapse
|
4
|
Srebro D, Dožić B, Vučković S, Savić Vujović K, Medić Brkić B, Dožić I, Srebro M. The Interactions of Magnesium Sulfate and Cromoglycate in a Rat Model of Orofacial Pain; The Role of Magnesium on Mast Cell Degranulation in Neuroinflammation. Int J Mol Sci 2023; 24:ijms24076241. [PMID: 37047214 PMCID: PMC10094402 DOI: 10.3390/ijms24076241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 03/29/2023] Open
Abstract
Mast cell degranulation impacts the development of pain and inflammation during tissue injury. We investigated the antinociceptive effect of a combination of cromoglycate and magnesium in the orofacial model of pain and the histological profile of the effect of magnesium in orofacial pain. In male Wistar rats, formalin (1.5%, 100 µL) was injected subcutaneously into the right upper lip of rats after cromoglycate and/or magnesium. Pain was measured as the total time spent on pain-related behavior. Toluidine blue staining was used to visualize mast cells under the light microscope. In the formalin test, in phase 1, magnesium antagonized the antinociceptive effect of cromoglycate, while in phase 2, it potentiated or inhibited its effect. Magnesium significantly reduced mast cell degranulation in the acute phase by about 23% and in the second phase by about 40%. Pearson’s coefficient did not show a significant correlation between mast cell degranulation and pain under treatment with magnesium. The cromoglycate–magnesium sulfate combination may prevent the development of inflammatory orofacial pain. The effect of a combination of cromoglycate–magnesium sulfate depends on the nature of the pain and the individual effects of the drugs. Magnesium reduced orofacial inflammation in the periphery, and this effect did not significantly contribute to its analgesic effect.
Collapse
Affiliation(s)
- Dragana Srebro
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Dr Subotića-Starijeg 1, 11129 Belgrade, Serbia; (D.S.)
| | - Branko Dožić
- Department of Pathology, School of Dental Medicine, University of Belgrade, Dr Subotića-Starijeg 1, 11000 Belgrade, Serbia
- Correspondence: or
| | - Sonja Vučković
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Dr Subotića-Starijeg 1, 11129 Belgrade, Serbia; (D.S.)
| | - Katarina Savić Vujović
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Dr Subotića-Starijeg 1, 11129 Belgrade, Serbia; (D.S.)
| | - Branislava Medić Brkić
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Dr Subotića-Starijeg 1, 11129 Belgrade, Serbia; (D.S.)
| | - Ivan Dožić
- Department of Biochemistry, School of Dental Medicine, University of Belgrade, Dr Subotića-Starijeg 1, 11000 Belgrade, Serbia
| | - Milorad Srebro
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Dr Subotića-Starijeg 1, 11129 Belgrade, Serbia; (D.S.)
| |
Collapse
|
5
|
Crescente G, Minervini G, Spagnuolo C, Moccia S. Cannabis Bioactive Compound-Based Formulations: New Perspectives for the Management of Orofacial Pain. MOLECULES (BASEL, SWITZERLAND) 2022; 28:molecules28010106. [PMID: 36615298 PMCID: PMC9822121 DOI: 10.3390/molecules28010106] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 12/06/2022] [Accepted: 12/20/2022] [Indexed: 12/24/2022]
Abstract
The management of orofacial pain to alleviate the quality of life of affected patients is becoming increasingly challenging for scientific research and healthcare professionals. From this perspective, in addition to conventional therapies, new alternatives are being sought, increasingly looking at the use of both natural and synthetic products. Cannabis sativa L. represents an interesting source of bioactive compounds, including non-psychoactive cannabinoids, flavonoids, and terpenes, many of which are effective in improving pain intensity. Here, we aim to analyze the possible mechanisms of action of the bioactive natural and synthetic hemp-derived compounds responsible for the modulatory effects on pain-related pathways. The ability of these compounds to act on multiple mechanisms through a synergistic effect, reducing both the release of inflammatory mediators and regulating the response of the endocannabinoid system, makes them interesting agents for alternative formulations to be used in orofacial pain.
Collapse
Affiliation(s)
| | - Giuseppe Minervini
- Multidisciplinary Department of Medical-Surgical and Dental Specialties, University of Campania, Luigi Vanvitelli, 80138 Naples, Italy
| | - Carmela Spagnuolo
- National Research Council, Institute of Food Sciences, 83100 Avellino, Italy
| | - Stefania Moccia
- National Research Council, Institute of Food Sciences, 83100 Avellino, Italy
- Correspondence: ; Tel.: +39-082-5299-423
| |
Collapse
|
6
|
Zubrzycki M, Zubrzycka M, Wysiadecki G, Szemraj J, Jerczynska H, Stasiolek M. Effect of Fatty Acid Amide Hydrolase Inhibitor URB597 on Orofacial Pain Perception in Rats. Int J Mol Sci 2022; 23:4665. [PMID: 35563056 PMCID: PMC9100922 DOI: 10.3390/ijms23094665] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/13/2022] [Accepted: 04/21/2022] [Indexed: 11/17/2022] Open
Abstract
Endocannabinoids act as analgesic agents in a number of headache models. However, their effectiveness varies with the route of administration and the type of pain. In this study, we assessed the role of the fatty acid amide hydrolase inhibitor URB597 in an animal model of orofacial pain based on tooth pulp stimulation. More specifically, we assessed the effects of intracerbroventricular (i.c.v.) and intraperitoneal (i.p.) administration of URB597 on the amplitude of evoked tongue jerks (ETJ) in rats. The levels of the investigated mediators anandamide (AEA), 2-arachidonyl glycerol (2-AG), Substance P (SP), calcitonin-gene-related peptide (CGRP), endomorphin-2 (EM-2) and fatty acid amide hydrolase (FAAH) inhibitor by URB597 and receptors cannabinoid type-1 receptors (CB1R), cannabinoid type-2 receptors (CB2R) and µ-opioid receptors (MOR) were determined in the mesencephalon, thalamus and hypothalamus tissues. We have shown that increasing endocannabinoid AEA levels by both central and peripheral inhibition of FAAH inhibitor by URB597 has an antinociceptive effect on the trigemino-hypoglossal reflex mediated by CB1R and influences the activation of the brain areas studied. On the other hand, URB597 had no effect on the concentration of 2-AG in the examined brain structures and caused a significant decrease in CB2R mRNA expression in the hypothalamus only. Tooth pulp stimulation caused in a significant increase in SP, CGRP and EM-2 gene expression in the midbrain, thalamus and hypothalamus. In contrast, URB597 administered peripherally one hour before stimulation decreased the mRNA level of these endogenous neuropeptides in comparison with the control and stimulation in all examined brain structures. Our results show that centrally and peripherally administered URB597 is effective at preventing orofacial pain by inhibiting AEA catabolism and reducing the level of CGRP, SP and EM-2 gene expression and that AEA and 2-AG have different species and model-specific regulatory mechanisms. The data presented in this study may represent a new promising therapeutic target in the treatment of orofacial pain.
Collapse
Affiliation(s)
- Marek Zubrzycki
- Department of Cardiac Surgery and Transplantology, The Cardinal Stefan Wyszynski Institute of Cardiology, Alpejska 42, 04-628 Warsaw, Poland
| | - Maria Zubrzycka
- Department of Clinical Physiology, Faculty of Medicine, Medical University of Lodz, Mazowiecka 6/8, 92-215 Lodz, Poland;
| | - Grzegorz Wysiadecki
- Department of Normal and Clinical Anatomy, Chair of Anatomy and Histology, Medical University of Lodz, Żeligowskiego 7/9, 90-752 Lodz, Poland;
| | - Janusz Szemraj
- Department of Medical Biochemistry, Medical University of Lodz, Mazowiecka 6/8, 92-215 Lodz, Poland;
| | - Hanna Jerczynska
- Central Scientific Laboratory (CoreLab), Medical University of Lodz, Mazowiecka 6/8, 92-215 Lodz, Poland;
| | - Mariusz Stasiolek
- Department of Neurology, Medical University of Lodz, Kopcinskiego 22, 90-153 Lodz, Poland;
| |
Collapse
|
7
|
Exercise Reduces Pain Behavior and Pathological Changes in Dorsal Root Ganglia Induced by Systemic Inflammation in Mice. Neurosci Lett 2022; 778:136616. [DOI: 10.1016/j.neulet.2022.136616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 03/11/2022] [Accepted: 04/01/2022] [Indexed: 11/23/2022]
|
8
|
Peripheral Purinergic Modulation in Pediatric Orofacial Inflammatory Pain Affects Brainstem Nitroxidergic System: A Translational Research. BIOMED RESEARCH INTERNATIONAL 2022; 2022:1326885. [PMID: 35309172 PMCID: PMC8933089 DOI: 10.1155/2022/1326885] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/19/2022] [Accepted: 01/22/2022] [Indexed: 11/18/2022]
Abstract
Physiology of orofacial pain pathways embraces primary afferent neurons, pathologic changes in the trigeminal ganglion, brainstem nociceptive neurons, and higher brain function regulating orofacial nociception. The goal of this study was to investigate the nitroxidergic system alteration at brainstem level (spinal trigeminal nucleus), and the role of peripheral P2 purinergic receptors in an experimental mouse model of pediatric inflammatory orofacial pain, to increase knowledge and supply information concerning orofacial pain in children and adolescents, like pediatric dentists and pathologists, as well as oro-maxillo-facial surgeons, may be asked to participate in the treatment of these patients. The experimental animals were treated subcutaneously in the perioral region with pyridoxalphosphate-6-azophenyl-2′,4′-disulphonic acid (PPADS), a P2 receptor antagonist, 30 minutes before formalin injection. The pain-related behavior and the nitroxidergic system alterations in the spinal trigeminal nucleus using immunohistochemistry and western blotting analysis have been evaluated. The local administration of PPADS decreased the face-rubbing activity and the expression of both neuronal and inducible nitric oxide (NO) synthase isoforms in the spinal trigeminal nucleus. These results underline a relationship between orofacial inflammatory pain and nitroxidergic system in the spinal trigeminal nucleus and suggest a role of peripheral P2 receptors in trigeminal pain transmission influencing NO production at central level. In this way, orofacial pain physiology should be elucidated and applied to clinical practice in the future.
Collapse
|
9
|
Chronic Orofacial Pain: Models, Mechanisms, and Genetic and Related Environmental Influences. Int J Mol Sci 2021; 22:ijms22137112. [PMID: 34281164 PMCID: PMC8268972 DOI: 10.3390/ijms22137112] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 12/13/2022] Open
Abstract
Chronic orofacial pain conditions can be particularly difficult to diagnose and treat because of their complexity and limited understanding of the mechanisms underlying their aetiology and pathogenesis. Furthermore, there is considerable variability between individuals in their susceptibility to risk factors predisposing them to the development and maintenance of chronic pain as well as in their expression of chronic pain features such as allodynia, hyperalgesia and extraterritorial sensory spread. The variability suggests that genetic as well as environmental factors may contribute to the development and maintenance of chronic orofacial pain. This article reviews these features of chronic orofacial pain, and outlines findings from studies in animal models of the behavioural characteristics and underlying mechanisms related to the development and maintenance of chronic orofacial pain and trigeminal neuropathic pain in particular. The review also considers the role of environmental and especially genetic factors in these models, focussing on findings of differences between animal strains in the features and underlying mechanisms of chronic pain. These findings are not only relevant to understanding underlying mechanisms and the variability between patients in the development, expression and maintenance of chronic orofacial pain, but also underscore the importance for considering the strain of the animal to model and explore chronic orofacial pain processes.
Collapse
|
10
|
Yeo JH, Kim SJ, Roh DH. Rapamycin reduces orofacial nociceptive responses and microglial p38 mitogen-activated protein kinase phosphorylation in trigeminal nucleus caudalis in mouse orofacial formalin model. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2021; 25:365-374. [PMID: 34187953 PMCID: PMC8255123 DOI: 10.4196/kjpp.2021.25.4.365] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 05/07/2021] [Accepted: 05/21/2021] [Indexed: 12/30/2022]
Abstract
The mammalian target of rapamycin (mTOR) plays a role in various cellular phenomena, including autophagy, cell proliferation, and differentiation. Although recent studies have reported its involvement in nociceptive responses in several pain models, whether mTOR is involved in orofacial pain processing is currently unexplored. This study determined whether rapamycin, an mTOR inhibitor, reduces nociceptive responses and the number of Fos-immunoreactive (Fos-ir) cells in the trigeminal nucleus caudalis (TNC) in a mouse orofacial formalin model. We also examined whether the glial cell expression and phosphorylated p38 (p-p38) mitogen-activated protein kinases (MAPKs) in the TNC are affected by rapamycin. Mice were intraperitoneally given rapamycin (0.1, 0.3, or 1.0 mg/kg); then, 30 min after, 5% formalin (10 µl) was subcutaneously injected into the right upper lip. The rubbing responses with the ipsilateral forepaw or hindpaw were counted for 45 min. High-dose rapamycin (1.0 mg/kg) produced significant antinociceptive effects in both the first and second phases of formalin test. The number of Fos-ir cells in the ipsilateral TNC was also reduced by high-dose rapamycin compared with vehicle-treated animals. Furthermore, the number of p-p38-ir cells the in ipsilateral TNC was significantly decreased in animals treated with high-dose rapamycin; p-p38 expression was co-localized in microglia, but not neurons and astrocytes. Therefore, the mTOR inhibitor, rapamycin, reduces orofacial nociception and Fos expression in the TNC, and its antinociceptive action on orofacial pain may be associated with the inhibition of p-p38 MAPK in the microglia.
Collapse
Affiliation(s)
- Ji-Hee Yeo
- Department of Oral Physiology, School of Dentistry, Kyung Hee University, Seoul 02447, Korea
| | - Sol-Ji Kim
- Department of Oral Physiology, School of Dentistry, Kyung Hee University, Seoul 02447, Korea
| | - Dae-Hyun Roh
- Department of Oral Physiology, School of Dentistry, Kyung Hee University, Seoul 02447, Korea
| |
Collapse
|
11
|
Affiliation(s)
- Menachem Hanani
- Laboratory of Experimental Surgery, Hadassah-Hebrew University Medical Center and Faculty of Medicine, the Hebrew University of Jerusalem, Jerusalem, Israel
| | - Robert W Banks
- Department of Biosciences, and Biophysical Sciences Institute, Durham University, Durham, UK
| |
Collapse
|
12
|
Meylakh N, Marciszewski KK, Di Pietro F, Macefield VG, Macey PM, Henderson LA. Brainstem functional oscillations across the migraine cycle: A longitudinal investigation. NEUROIMAGE-CLINICAL 2021; 30:102630. [PMID: 33770547 PMCID: PMC8024773 DOI: 10.1016/j.nicl.2021.102630] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 03/07/2021] [Accepted: 03/09/2021] [Indexed: 12/30/2022]
Abstract
Individual migraineurs’ brainstem function alters through the migraine cycle. Functional changes occurred in the 24-hour period immediately prior to a migraine. Greater resting activity variability was found in the SpV, pons and PAG. Increased infra-slow oscillations and regional homogeneity in the SpV and pons.
Although the mechanisms responsible for migraine initiation remain unknown, recent evidence shows that brain function is different immediately preceding a migraine. This is consistent with the idea that altered brain function, particularly in brainstem sites, may either trigger a migraine or facilitate a peripheral trigger that activates the brain, resulting in pain. The aim of this longitudinal study is therefore to expand on the above findings, and to determine if brainstem function oscillates over a migraine cycle in individual subjects. We performed resting state functional magnetic resonance imaging in three migraineurs and five controls each weekday for four weeks. We found that although resting activity variability was similar in controls and interictal migraineurs, brainstem variability increased dramatically during the 24-hour period preceding a migraine. This increase occurred in brainstem areas in which orofacial afferents terminate: the spinal trigeminal nucleus and dorsal pons. These increases were characterized by increased power at infra-slow frequencies, principally between 0.03 and 0.06 Hz. Furthermore, these power increases were associated with increased regional homogeneity, a measure of local signal coherence. The results show within-individual alterations in brain activity immediately preceding migraine onset and support the hypothesis that altered regional brainstem function before a migraine attack is involved in underlying migraine neurobiology.
Collapse
Affiliation(s)
- Noemi Meylakh
- Department of Anatomy and Histology, University of Sydney, Sydney, NSW 2006, Australia.
| | - Kasia K Marciszewski
- Department of Anatomy and Histology, University of Sydney, Sydney, NSW 2006, Australia
| | - Flavia Di Pietro
- School of Pharmacy and Biomedical Sciences, Curtin University, Perth, Australia
| | | | - Paul M Macey
- UCLA School of Nursing and Brain Research Institute, University of California, Los Angeles, CA 90095, United States
| | - Luke A Henderson
- Department of Anatomy and Histology, University of Sydney, Sydney, NSW 2006, Australia
| |
Collapse
|
13
|
Kanno K, Shimizu K, Shinoda M, Hayashi M, Takeichi O, Iwata K. Role of macrophage-mediated Toll-like receptor 4-interleukin-1R signaling in ectopic tongue pain associated with tooth pulp inflammation. J Neuroinflammation 2020; 17:312. [PMID: 33081813 PMCID: PMC7576725 DOI: 10.1186/s12974-020-01995-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 10/08/2020] [Indexed: 01/16/2023] Open
Abstract
Background The existence of referred pain and ectopic paresthesia caused by tooth pulp inflammation may make definitive diagnosis difficult and cause misdiagnosis or mistreatment; thus, elucidation of that molecular mechanism is urgent. In the present study, we investigated the mechanisms underlying ectopic pain, especially tongue hyperalgesia, after tooth pulp inflammation. Methods A rat model with mandibular first molar tooth pulp exposure was employed. Tooth pulp exposure-induced heat and mechanical-evoked tongue hypersensitivity was measured, and immunohistochemical staining for Iba1, a marker of active macrophages, IL-1β, IL-1 type I receptor (IL-1RΙ), and toll-like receptor 4 in the trigeminal ganglion was performed. In addition, we investigated the effects of injections of liposomal clodronate Clophosome-A (LCCA), a selective macrophage depletion agent, lipopolysaccharide from Rhodobacter sphaeroides (LPS-RS, a toll-like receptor 4 antagonist), IL-1β, or heat shock protein 70 (Hsp70, a selective agonist of toll-like receptor 4), to examine changes in tongue hypersensitivity and in the regulation of IL-1RΙ, toll-like receptor 4, and transient receptor potential vanilloid 1 (TRPV1) biosynthesis. Results At day 1 after tooth pulp exposure, obvious tooth pulp inflammation was observed. Tooth pulp exposure-induced heat and mechanical tongue hypersensitivity was observed from days 1 to 3 after tooth pulp exposure. The production of IL-1β in activated macrophages and toll-like receptor 4 and IL-1RΙ expression were significantly increased in trigeminal ganglion neurons innervating the tongue following tooth pulp exposure. Intra-trigeminal ganglion injection of LCCA significantly suppressed tongue hypersensitivity; however, toll-like receptor 4 and IL-1RΙ expression in trigeminal ganglion neurons innervating the tongue was not significantly altered. Intra-trigeminal ganglion injection of LPS-RS significantly suppressed tongue hypersensitivity and reduced IL-1RΙ expression in the trigeminal ganglion neurons innervating the tongue following tooth pulp exposure. Intra-trigeminal ganglion injection of recombinant Hsp70 significantly promoted tongue hypersensitivity and increased IL-1RI expression in trigeminal ganglion neurons innervating the tongue in naive rats. Furthermore, intra-trigeminal ganglion injection of recombinant IL-1β led to tongue hypersensitivity and enhanced TRPV1 expression in trigeminal ganglion neurons innervating the tongue in naive rats. Conclusions The present findings suggest that the neuron-macrophage interaction mediated by toll-like receptor 4 and IL-1RI activation in trigeminal ganglion neurons affects the pathogenesis of abnormal tongue pain following tooth pulp inflammation via IL-1RI and TRPV1 signaling in the trigeminal ganglion. Further research may contribute to the establishment of new therapeutic and diagnostic methods.
Collapse
Affiliation(s)
- Kohei Kanno
- Department of Endodontics, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo, 101-8310, Japan
| | - Kohei Shimizu
- Department of Endodontics, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo, 101-8310, Japan. .,Division of Advanced Dental Treatment, Dental Research Center, Nihon University School of Dentistry, Tokyo, Japan.
| | - Masamichi Shinoda
- Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan.,Division of Functional Morphology, Dental Research Center, Nihon University School of Dentistry, Tokyo, Japan
| | - Makoto Hayashi
- Department of Endodontics, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo, 101-8310, Japan.,Division of Advanced Dental Treatment, Dental Research Center, Nihon University School of Dentistry, Tokyo, Japan
| | - Osamu Takeichi
- Department of Endodontics, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo, 101-8310, Japan.,Division of Advanced Dental Treatment, Dental Research Center, Nihon University School of Dentistry, Tokyo, Japan
| | - Koichi Iwata
- Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan.,Division of Functional Morphology, Dental Research Center, Nihon University School of Dentistry, Tokyo, Japan
| |
Collapse
|
14
|
Yoon D, Kogan F, Gold GE, Biswal S. Identifying Musculoskeletal Pain Generators Using Clinical PET. Semin Musculoskelet Radiol 2020; 24:441-450. [DOI: 10.1055/s-0040-1713607] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
AbstractIdentifying the source of a person's pain is a significant clinical challenge because the physical sensation of pain is believed to be subjective and difficult to quantify. The experience of pain is not only modulated by the individual's threshold to painful stimuli but also a product of the person's affective contributions, such as fear, anxiety, and previous experiences. Perhaps then to quantify pain is to examine the degree of nociception and pro-nociceptive inflammation, that is, the extent of cellular, chemical, and molecular changes that occur in pain-generating processes. Measuring changes in the local density of receptors, ion channels, mediators, and inflammatory/immune cells that are involved in the painful phenotype using targeted, highly sensitive, and specific positron emission tomography (PET) radiotracers is therefore a promising approach toward objectively identifying peripheral pain generators. Although several preclinical radiotracer candidates are being developed, a growing number of ongoing clinical PET imaging approaches can measure the degree of target concentration and thus serve as a readout for sites of pain generation. Further, when PET is combined with the spatial and contrast resolution afforded by magnetic resonance imaging, nuclear medicine physicians and radiologists can potentially identify pain drivers with greater accuracy and confidence. Clinical PET imaging approaches with fluorine-18 fluorodeoxyglucose, fluorine-18 sodium fluoride, and sigma-1 receptor PET radioligand and translocator protein radioligands to isolate the source of pain are described here.
Collapse
Affiliation(s)
- Daehyun Yoon
- Division of Musculoskeletal Radiology, Department of Radiology, Stanford University School of Medicine, Stanford, California
| | - Feliks Kogan
- Division of Musculoskeletal Radiology, Department of Radiology, Stanford University School of Medicine, Stanford, California
| | - Garry E. Gold
- Division of Musculoskeletal Radiology, Department of Radiology, Stanford University School of Medicine, Stanford, California
| | - Sandip Biswal
- Division of Musculoskeletal Radiology, Department of Radiology, Stanford University School of Medicine, Stanford, California
| |
Collapse
|