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Hu QQ, He XF, Ma YQ, Ma LQ, Qu SY, Wang HZ, Kang YR, Chen LH, Li X, Liu BY, Shao XM, Fang JF, Liang Y, Fang JQ, Jiang YL. Dorsal root ganglia P2X4 and P2X7 receptors contribute to diabetes-induced hyperalgesia and the downregulation of electroacupuncture on P2X4 and P2X7. Purinergic Signal 2023; 19:29-41. [PMID: 35218450 PMCID: PMC9984662 DOI: 10.1007/s11302-022-09844-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 01/11/2022] [Indexed: 12/11/2022] Open
Abstract
Diabetic neuropathic pain (DNP) is highly common in diabetes patients. P2X receptors play critical roles in pain sensitization. We previously showed that elevated P2X3 expression in dorsal root ganglion (DRG) contributes to DNP. However, the role of other P2X receptors in DNP is unclear. Here, we established the DNP model using a single high-dose streptozotocin (STZ) injection and investigated the expression of P2X genes in the DRG. Our data revealed elevated P2X2, P2X4, and P2X7 mRNA levels in DRG of DNP rats. The protein levels of P2X4 and P2X7 in DNP rats increased, but the P2X2 did not change significantly. To study the role of P2X4 and P2X7 in diabetes-induced hyperalgesia, we treated the DNP rats with TNP-ATP (2',3'-O-(2,4,6-trinitrophenyl)-adenosine 5'-triphosphate), a nonspecific P2X1-7 antagonist, and found that TNP-ATP alleviated thermal hyperalgesia in DNP rats. 2 Hz electroacupuncture is analgesic against DNP and could downregulate P2X4 and P2X7 expression in DRG. Our findings indicate that P2X4 and P2X7 in L4-L6 DRGs contribute to diabetes-induced hyperalgesia, and that EA reduces thermal hyperalgesia and the expression of P2X4 and P2X7.
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Affiliation(s)
- Qun-Qi Hu
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, People's Republic of China
| | - Xiao-Fen He
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, People's Republic of China
| | - Yi-Qi Ma
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, People's Republic of China
| | - Li-Qian Ma
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, People's Republic of China
| | - Si-Ying Qu
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, People's Republic of China
| | - Han-Zhi Wang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, People's Republic of China
| | - Yu-Rong Kang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, People's Republic of China
| | - Lu-Hang Chen
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, People's Republic of China
| | - Xiang Li
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, People's Republic of China
| | - Bo-Yu Liu
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, People's Republic of China
| | - Xiao-Mei Shao
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, People's Republic of China
| | - Jun-Fan Fang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, People's Republic of China
| | - Yi Liang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, People's Republic of China
| | - Jian-Qiao Fang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, People's Republic of China.
| | - Yong-Liang Jiang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, People's Republic of China.
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Li YK, Zhang YY, Lin J, Liu YJ, Li YL, Feng YH, Zhao JS, Zhou C, Liu F, Shen JF. Metabotropic glutamate receptor 5-mediated inhibition of inward-rectifying K + channel 4.1 contributes to orofacial ectopic mechanical allodynia following inferior alveolar nerve transection in male mice. J Neurosci Res 2023; 101:1170-1187. [PMID: 36807930 DOI: 10.1002/jnr.25181] [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: 07/20/2022] [Revised: 01/20/2023] [Accepted: 01/31/2023] [Indexed: 02/20/2023]
Abstract
Inward-rectifying K+ channel 4.1 (Kir4.1), which regulates the electrophysiological properties of neurons and glia by affecting K+ homeostasis, plays a critical role in neuropathic pain. Metabotropic glutamate receptor 5 (mGluR5) regulates the expression of Kir4.1 in retinal Müller cells. However, the role of Kir4.1 and its expressional regulatory mechanisms underlying orofacial ectopic allodynia remain unclear. This study aimed to investigate the biological roles of Kir4.1 and mGluR5 in the trigeminal ganglion (TG) in orofacial ectopic mechanical allodynia and the role of mGluR5 in Kir4.1 regulation. An animal model of nerve injury was established via inferior alveolar nerve transection (IANX) in male C57BL/6J mice. Behavioral tests indicated that mechanical allodynia in the ipsilateral whisker pad lasted at least 14 days after IANX surgery and was alleviated by the overexpression of Kir4.1 in the TG, as well as intraganglionic injection of an mGluR5 antagonist (MPEP hydrochloride) or a protein kinase C (PKC) inhibitor (chelerythrine chloride); Conditional knockdown of the Kir4.1 gene downregulated mechanical thresholds in the whisker pad. Double immunostaining revealed that Kir4.1 and mGluR5 were co-expressed in satellite glial cells in the TG. IANX downregulated Kir4.1 and upregulated mGluR5 and phosphorylated PKC (p-PKC) in the TG; Inhibition of mGluR5 reversed the changes in Kir4.1 and p-PKC that were induced by IANX; Inhibition of PKC activation reversed the downregulation of Kir4.1 expression caused by IANX (p < .05). In conclusion, activation of mGluR5 in the TG after IANX contributed to orofacial ectopic mechanical allodynia by suppressing Kir4.1 via the PKC signaling pathway.
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Affiliation(s)
- Yi-Ke Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, National Center of Stomatology, West China Hospital 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 of Stomatology, West China Hospital 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 of Stomatology, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ya-Jing Liu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, National Center of Stomatology, West China Hospital 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 of Stomatology, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yu-Heng Feng
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, National Center of Stomatology, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jia-Shuo Zhao
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, National Center of Stomatology, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Cheng Zhou
- Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, China
| | - Fei Liu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, National Center of Stomatology, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jie-Fei Shen
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, National Center of Stomatology, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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Du J, Yi M, Xi D, Wang S, Liu B, Shao X, Liang Y, He X, Fang J, Fang J. Satellite glial cells drive the transition from acute to chronic pain in a rat model of hyperalgesic priming. Front Mol Neurosci 2023; 16:1089162. [PMID: 36818653 PMCID: PMC9931746 DOI: 10.3389/fnmol.2023.1089162] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 01/18/2023] [Indexed: 02/05/2023] Open
Abstract
Chronic pain is one of the most common clinical syndromes affecting patients' quality of life. Regulating the transition from acute to chronic pain is a novel therapeutic strategy for chronic pain that presents a major clinical challenge. However, the mechanism underlying pain transitions remains poorly understood. A rat hyperalgesic priming (HP) model, which mimics pain transition, was established decades ago. Here, this HP model and RNA sequencing (RNA-seq) were used to study the potential role of neuroinflammation in pain transition. In this study, HP model rats developed prolonged hyperalgesia in the hind paw after carrageenan (Car) and PGE2 injection, accompanied by obvious satellite glial cell (SGC) activation in the dorsal root ganglion (DRG), as indicated by upregulation of GFAP. RNA-Seq identified a total of differentially expressed genes in the ipsilateral DRG in HP model rats. The expression of several representative genes was confirmed by real-time quantitative PCR (qPCR). Functional analysis of the differentially expressed genes indicated that genes related to the inflammatory and neuroinflammatory response showed the most significant changes in expression. We further found that the expression of the chemokine CXCL1 was significantly upregulated in the rat DRG. Pharmacological blockade of CXCL1 reduced protein kinase C epsilon overproduction as well as hyperalgesia in HP rats but did not prevent the upregulation of GFAP in the DRG. These results reveal that neuroinflammatory responses are involved in pain transition and may be the source of chronic pain. The chemokine CXCL1 in the DRG is a pivotal contributor to chronic pain and pain transition in HP model rats. Thus, our study provides a putative novel target for the development of effective therapeutics to prevent pain transition.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Junfan Fang
- *Correspondence: Jianqiao Fang, ; Junfan Fang,
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4
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Shi M, Zhou J, Hu R, Xu H, Chen Y, Wu X, Chen B, Ma R. EA participates in pain transition through regulating KCC2 expression by BDNF-TrkB in the spinal cord dorsal horn of male rats. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2023; 13:100115. [PMID: 36875547 PMCID: PMC9982673 DOI: 10.1016/j.ynpai.2023.100115] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/04/2023] [Accepted: 01/04/2023] [Indexed: 06/18/2023]
Abstract
The pathogenesis of chronic pain is complex and poorly treated, seriously affecting the quality of life of patients. Electroacupuncture (EA) relieves pain by preventing the transition of acute pain into chronic pain, but its mechanism of action is still unclear. Here, we aimed to investigate whether EA can inhibit pain transition by increasing KCC2 expression via BDNF-TrkB. We used hyperalgesic priming (HP) model to investigate the potential central mechanisms of EA intervention on pain transition. HP model male rats showed significant and persistent mechanically abnormal pain. Brain derived neurotrophic factor (BDNF) expression and Tropomyosin receptor kinase B (TrkB) phosphorylation were upregulated in the affected spinal cord dorsal horn (SCDH) of HP model rats, accompanied by K+-Cl-- Cotransporter-2 (KCC2) expression was down-regulated. EA significantly increased the mechanical pain threshold in HP model male rats and decreased BDNF and p-TrkB overexpression and upregulated KCC2 expression. Blockade of BDNF with BDNF neutralizing antibody attenuated mechanical abnormal pain in HP rats. Finally, administration of exogenous BDNF by pharmacological methods reversed the EA-induced resistance to abnormal pain. In all, these results suggest that BDNF-TrkB contributes to mechanical abnormal pain in HP model rats and that EA ameliorates mechanical abnormal pain through upregulation of KCC2 by BDNF-TrkB in SCDH. Our study further supports EA as an effective treatment to prevent the transition of acute pain into chronic pain.
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Affiliation(s)
- Mengting Shi
- The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, Zhejiang, China
| | - Jie Zhou
- The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, Zhejiang, China
- Department of Acupuncture and Moxibustion, Third Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Rong Hu
- The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, Zhejiang, China
| | - Haipeng Xu
- The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, Zhejiang, China
| | - Yi Chen
- The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, Zhejiang, China
| | - Xingying Wu
- The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, Zhejiang, China
| | - Bowen Chen
- The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, Zhejiang, China
| | - Ruijie Ma
- The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, Zhejiang, China
- Department of Acupuncture and Moxibustion, Third Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
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5
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Sun HJ, Li XY, Wang SS, Shao XM, Du JY, Fang JQ, Fang JF. Intervention mechanism of electroacupuncture on the EP1-TRPV1 pathway in the dorsal root ganglion of rats in the transition from acute to chronic pain. WORLD JOURNAL OF ACUPUNCTURE-MOXIBUSTION 2022. [DOI: 10.1016/j.wjam.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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Li Y, Kang J, Xu Y, Li N, Jiao Y, Wang C, Wang C, Wang G, Yu Y, Yuan J, Zhang L. Artesunate Alleviates Paclitaxel-Induced Neuropathic Pain in Mice by Decreasing Metabotropic Glutamate Receptor 5 Activity and Neuroinflammation in Primary Sensory Neurons. Front Mol Neurosci 2022; 15:902572. [PMID: 35694442 PMCID: PMC9184756 DOI: 10.3389/fnmol.2022.902572] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 05/09/2022] [Indexed: 11/22/2022] Open
Abstract
Experimental studies on the pathogenetic process of paclitaxel-induced neuropathic pain (PINP) have been initially carried out, but PINP still has no effective therapy. Recently reported studies have highlighted the involvement of glutamate receptors and neuroinflammation in peripheral and central nociceptive transmission in PINP. Artesunate is a first-line antimalarial drug with established efficacy in alleviating pain in a variety of pathologies. The current work assessed whether artesunate inhibits PINP by modulating metabotropic glutamate receptor 5 (mGluR5) and neuroinflammation in mice. The anti-hyperalgesic effect of artesunate was verified by assessing mechanical frequency and thermal latency in the paw withdrawal test as well as spontaneous pain. The expression levels of mGluR5, pain-related receptors and neuroinflammatory markers in dorsal root ganglion (DRG) were examined. In addition, treatment with CHPG and 2-methyl-6-(phenyl ethynyl) pyridine (MPEP) (mGluR5 agonist and antagonist, respectively) was performed to determine mGluR5’s role in the anti-hyperalgesic properties of artesunate. We demonstrated artesunate prevented PINP in a dose-dependent manner, while exerting a clear anti-hyperalgesic effect on already existing PINP. Artesunate normalized paclitaxel-related expression changes in DRG mGluR5, NR1, and GluA2, as well as six paclitaxel related neuroinflammation markers. Intrathecal application of MPEP treated PINP by reversing NR1 and GluA2 expression changes but had no effects on chemokines and inflammatory factors. Furthermore, artesunate treatment reversed acute pain following CHPG application. In conclusion, this study revealed that artesunate alleviates paclitaxel-induced hyperalgesia and spontaneous pain by decreasing DRG mGluR5 expression and neuroinflammation in the mouse model of PINP.
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Affiliation(s)
- Yize Li
- Department of Anesthesiology, Tianjin Research Institute of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Jiamin Kang
- Department of Anesthesiology, Tianjin Research Institute of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Ying Xu
- Department of Anesthesiology, Tianjin Research Institute of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Nan Li
- Department of Anesthesiology, Tianjin Research Institute of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Yang Jiao
- Department of Anesthesiology, Tianjin Research Institute of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Chenxu Wang
- Department of Anesthesiology, Tianjin Research Institute of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Chunyan Wang
- Department of Anesthesiology, Tianjin Research Institute of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Guolin Wang
- Department of Anesthesiology, Tianjin Research Institute of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Yonghao Yu
- Department of Anesthesiology, Tianjin Research Institute of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Jingjing Yuan
- Department of Anesthesiology, Pain and Perioperative Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- *Correspondence: Jingjing Yuan,
| | - Linlin Zhang
- Department of Anesthesiology, Tianjin Research Institute of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
- Linlin Zhang,
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Strong Twirling-Rotating Manual Acupuncture with 4 r/s Is Superior to 2 r/s in Relieving Pain by Activating C-Fibers in Rat Models of CFA-Induced Pain. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2021; 2021:5528780. [PMID: 34675986 PMCID: PMC8526210 DOI: 10.1155/2021/5528780] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 06/23/2021] [Accepted: 08/29/2021] [Indexed: 12/22/2022]
Abstract
Background Manual acupuncture (MA) with different stimulus frequencies may give rise to varying acupuncture effects. However, the intensity-effect relationship and the underlying mechanisms of MA remain unclear. Objective To compare the analgesic effects of different frequencies of twirling-rotating MA on rats with complete Freund's adjuvant- (CFA-) induced pain and explore the underlying mechanism via peripheral sensory nerves. Methods First, 36 healthy male Wistar rats were randomly divided into 6 groups: control group, 2 r/s MA group (twirling-rotating MA with the frequency of 2 revolutions per second), 4 r/s MA group (twirling-rotating MA with the frequency of 4 revolutions per second), CFA group, CFA + 2 r/s MA group, and CFA + 4 r/s MA group. Rats in three CFA groups received an intraplantar injection of CFA to establish a pain model, while the rats in other three groups received an intraplantar injection of saline. Rats in the 2 r/s MA group and 4 r/s MA group were treated with the corresponding frequencies of twirling-rotating MA on bilateral Zusanli (ST36) and Kunlun (BL60) for 7 days. The ipsilateral nociceptive thresholds (paw withdrawal latency; PWL) were tested to evaluate the analgesic effects. Second, 9 healthy male Wistar rats were randomly divided into 3 groups: control group, 2 r/s MA group, and 4 r/s MA group. The proportion of C-fiber neurons (calcitonin gene-related peptide- (CGRP-) positive neurons) and A-fiber neurons (neurofilament 200- (NF200-) positive neurons) in the dorsal root ganglia (DRG) activated by MA were quantitatively analyzed with the morphological immunofluorescence staining method. Third, 30 healthy male Wistar rats were randomly divided into 6 groups: control group, CFA group, CFA + 2 r/s MA group, CFA + 2 r/s MA + RTX group, CFA + 4 r/s MA group, and CFA + 4 r/s MA + RTX group. Resiniferatoxin (RTX) was injected into the acupoints before acupuncture. PWL was evaluated to investigate the analgesic effect. Results Both types of MA treatment increased the PWL of saline-injecting rats and pain model rats. Moreover, 4 r/s MA was superior to 2 r/s MA in increasing PWL. A higher quantity of excited C-fiber neurons was observed following 4 r/s MA than 2 r/s MA, while the reverse was observed in the activation of A-fiber neurons. Following the injection of RTX to inhibit the activation of C-fibers, the analgesic effect of 4 r/s MA reduced significantly but not of 2 r/s MA. Conclusion Strong MA (4 r/s MA) has superior analgesic effects to gentle MA (2 r/s MA) on CFA model rats, which is associated with C-fiber activation.
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Fang J, Wang S, Zhou J, Shao X, Sun H, Liang Y, He X, Jiang Y, Liu B, Jin X, Fang J, Du J. Electroacupuncture Regulates Pain Transition Through Inhibiting PKCε and TRPV1 Expression in Dorsal Root Ganglion. Front Neurosci 2021; 15:685715. [PMID: 34354561 PMCID: PMC8329384 DOI: 10.3389/fnins.2021.685715] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/28/2021] [Indexed: 11/16/2022] Open
Abstract
Many cases of acute pain can be resolved with few side effects. However, some cases of acute pain may persist beyond the time required for tissue injury recovery and transit to chronic pain, which is hard to treat. The mechanisms underlying pain transition are not entirely understood, and treatment strategies are lacking. In this study, the hyperalgesic priming model was established on rats to study pain transition by injection of carrageenan (Car) and prostaglandin E2 (PGE2). The expression levels of protein kinase C epsilon (PKCε) and transient receptor potential vanilloid 1 (TRPV1) in the L4–L6 dorsal root ganglion (DRG) were investigated. Electroacupuncture (EA) is a form of acupuncture in which a small electric current is passed between a pair of acupuncture needles. EA was administrated, and its effect on hyperalgesia and PKCε and TRPV1 expression was investigated. The PKCε–TRPV1 signaling pathway in DRG was implicated in the pain transition. EA increased the pain threshold of model animals and regulated the high expression of PKCε and TRPV1. Moreover, EA also regulated hyperalgesia and high TRPV1 expression induced by selective PKCε activation. We also found that EA partly increased chronic pain threshold, even though it was only administered between the Car and PGE2 injections. These findings suggested that EA could prevent the transition from acute to chronic pain by inhibiting the PKCε and TRPV1 expression in the peripheral nervous system.
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Affiliation(s)
- Junfan Fang
- Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, China
| | - Sisi Wang
- Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, China
| | - Jie Zhou
- Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, China
| | - Xiaomei Shao
- Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, China
| | - Haiju Sun
- Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, China
| | - Yi Liang
- Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, China
| | - Xiaofen He
- Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, China
| | - Yongliang Jiang
- Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, China
| | - Boyi Liu
- Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, China
| | - Xiaoming Jin
- Department of Anatomy, Cell Biology and Physiology, Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Jianqiao Fang
- Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, China
| | - Junying Du
- Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, China
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9
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Wang S, Du J, Xi D, Shao F, Qiu M, Shao X, Liang Y, Liu B, Jin X, Fang J, Fang J. Role of GABAAR in the Transition From Acute to Chronic Pain and the Analgesic Effect of Electroacupuncture on Hyperalgesic Priming Model Rats. Front Neurosci 2021; 15:691455. [PMID: 34220444 PMCID: PMC8248374 DOI: 10.3389/fnins.2021.691455] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 05/25/2021] [Indexed: 11/18/2022] Open
Abstract
Chronic pain is a costly health problem that impairs health-related quality of life when not effectively treated. Regulating the transition from acute to chronic pain is a new therapeutic strategy for chronic pain that presents a major clinical challenge. The underlying mechanisms of pain transition are not entirely understood, and strategies for preventing this transition are lacking. Here, a hyperalgesic priming model was used to study the potential mechanism by which γ-aminobutyric acid receptor type A (GABAAR) in the dorsal root ganglion (DRG) contributes to pain transition. Furthermore, electroacupuncture (EA), a modern method of acupuncture, was administered to regulate pain transition, and the mechanism underlying EA’s regulatory effect was investigated. Hyperalgesic priming was induced by intraplanar injection of carrageenan (Car)/prostaglandin E2 (PGE2). The decrease in mechanical withdrawal threshold (MWT) induced by PGE2 returned to baseline 4 h after injection in NS + PGE2 group, and still persisted 24 h after injection in Car + PGE2 group. Lower expression of GABAAR in the lumbar DRG was observed in the model rats. Furthermore, activating or blocking GABAAR could reversed the long-lasting hyperalgesia induced by Car/PGE2 injection or produced a persistent hyperalgesia. In addition, GABAAR may be involved in Protein Kinase C epsilon (PKCε) activation in the DRG, a mark molecular of pain transition. EA considerably increased the mechanical pain thresholds of hyperalgesic priming model mammals in both the acute and chronic phases. Furthermore, EA upregulated the expression of GABAAR and inhibited the activation of PKCε in the DRG. In addition, peripheral administration of picrotoxin blocked the analgesic effect of EA on the model rats and abolished the regulatory effect of EA on PKCε activation. These findings suggested that GABAAR plays a key role in both the transition from acute to chronic pain and the analgesic effect of EA on hyperalgesic priming.
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Affiliation(s)
- Sisi Wang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - Junying Du
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - Danning Xi
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - Fangbing Shao
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - Mengting Qiu
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - Xiaomei Shao
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yi Liang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - Boyi Liu
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - Xiaomin Jin
- Department of Anatomy, Cell Biology and Physiology, Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Jianqiao Fang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - Junfan Fang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture Research, The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou, China
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