Brazilian Journal of Pain
https://brjp.org.br/article/doi/10.63231/2595-0118.e202556-en
Brazilian Journal of Pain
Review Article

Mechanisms of acupuncture- and electroacupuncture induced analgesia in individuals with chronic pain: systematic review 

Mecanismos de ação da analgesia induzida pela acupuntura e eletroacupuntura em indivíduos com dor crônica: revisão sistemática

Ana Carolina Kussunoki Orsi; Lucas Almeida Baptista; Valquiria Hanai-Yoshida; Paula Araujo

http://dx.doi.org/10.63231/2595-0118.e202556-en BrJP, vol.8, e202556, 2026
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Abstract

BACKGROUND AND OBJECTIVES: Acupuncture has been widely used as a complementary therapy for chronic pain syndromes. However; the neurobiological mechanisms underlying its analgesic effects are not yet fully understood. The objective of this study was to investigate the mechanisms of acupuncture-induced analgesia in individuals with chronic pain.

CONTENTS: Searches were conducted in Pubmed; Scopus; Web of Science; Embase; and LILACS. Two independent reviewers selected the studies; extracted data; and assessed the risk of bias using the RoB2 and ROBINS-I tools. From 1;558 records; four studies were included (three randomized clinical trials and one non-randomized study); three involving knee osteoarthritis and one fibromyalgia. All studies demonstrated a significant analgesic effect of acupuncture. The most frequently used acupoints were E35; VB34 e BP6. Three articles evaluated central mechanisms of analgesia (using fMRI or PET); and one assessed blood hormone concentrations. Neuroimaging results indicated changes in neural connectivity within circuits related to the emotional modulation of pain; as well as increased µ-opioid receptor binding. Hormonal data showed increased beta-endorphin and reduced cortisol associated with analgesia. All studies exhibited some degree of risk of bias.

CONCLUSION: Acupuncture appears to be effective in reducing pain in chronic pain conditions; possibly through central and peripheral modulation of pain pathways. However, these findings should be interpreted with caution due to the limited number of studies; heterogeneity of acupoint selection; and the risk of bias in the included studies.

Keywords

Acupuncture therapy; Analgesia; Chronic pain; Electroacupuncture

Resumo

JUSTIFICATIVA E OBJETIVOS: A acupuntura tem sido amplamente utilizada como terapia complementar para diversas síndromes dolorosas crônicas. No entanto; os mecanismos neurobiológicos da ação analgésica da acupuntura ainda não estão completamente esclarecidos. O objetivo deste estudo foi investigar os mecanismos da analgesia induzida pela acupuntura em indivíduos com dor crônica.

CONTEÚDO: Foram realizadas buscas nas bases Pubmed; Scopus; Web of Science; Embase e LILACS. Dois revisores independentes selecionaram os estudos; extraíram os dados e avaliaram o risco de viés por meio das ferramentas RoB2 e ROBINS-I. De 1.558 registros; quatro estudos foram incluídos (três ensaios clínicos randomizados e um não randomizado); três abordando osteoartrite de joelho e um fibromialgia. Todos os estudos demonstraram efeito significativo da acupuntura na redução da dor. Os pontos de acupuntura mais utilizados foram E35; VB34 e BP6. Três artigos avaliaram mecanismos centrais da analgesia (utilizando fMRI ou PET) e um analisou concentrações hormonais no sangue. Os resultados dos estudos de imagem demonstraram alterações na conectividade neural em circuitos relacionados à modulação emocional da dor e maior ligação de receptores µ-opioides. Os dados hormonais indicaram aumento de beta-endorfina e redução de cortisol associados à analgesia. Todos os estudos apresentaram algum risco de viés.

CONCLUSÃO: A acupuntura parece ser eficaz na redução da dor em condições dolorosas crônicas; possivelmente por meio da modulação central e periférica das vias da dor. Entretanto; os resultados devem ser interpretados com cautela devido ao número limitado de estudos; à heterogeneidade dos pontos de acupuntura e ao risco de viés nos estudos incluídos.

Palavras-chave

Acupuntura; Analgesia; Dor crônica; Eletroacupuntura

References

1 Raja SN, Carr DB, Cohen M, Finnerup NB, Flor H, Gibson S, Keefe FJ, Mogil JS, Ringkamp M, Sluka KA, Song XJ, Stevens B, Sullivan MD, Tutelman PR, Ushida T, Vader K. The revised IASP definition of pain: concepts, challenges, and compromises. Pain. 2020;161(9):1976-82. https://doi.org/10.1097/j.pain.0000000000001939.

2 Aguggia M. Neurophysiology of pain. Neurol Sci. 2003;24(Suppl 2):S57-60. https://doi.org/10.1007/s100720300042.

3 Treed RD, Rief W, Barke A, Aziz Q, Bennett MI, Benoliel R, Cohen M, Evers S, Finnerup NB, First MB, Giamberardino MA, Kaasa S, Korwisi B, Kosek E, Lavand’homme P, Nicholas M, Perrot S, Scholz J, Schug S, Smith BH, Svensson P, Vlaeyen JWS, Wang SJ. Chronic pain as a symptom or a disease: the IASP Classification of Chronic Pain for the International Classification of Diseases (ICD-11). Pain. 2019;160(1):19-27. https://doi.org/10.1097/j.pain.0000000000001384. PMid:30586067.

4 Niruthisard S, Ma Q, Napadow V. Recent advances in acupuncture for pain relief. PAIN Repo. 2024;9(5):e1188. https://doi.org/10.1097/PR9.0000000000001188.

5 Han JS. Acupuncture analgesia: areas of consensus and controversy. Pain. 2011;152(3):S41-48. https://doi.org/10.1016/j.pain.2010.10.012.

6 Zhang XC, Chen H, Xu WT, Song YY, Gu YH, Ni GX. Acupuncture therapy for fibromyalgia: a systematic review and meta-analysis of randomized controlled trials. J Pain Res. 2019;12:527-42. https://doi.org/10.2147/JPR.S186227. PMid:30787631.

7 Macfarlane GJ, Kronisch C, Dean LE, Atzeni F, Häuser W, Fluß E, Choy E, Kosek E, Amris K, Branco J, Dincer F, Leino-Arjas P, Longley K, McCarthy GM, Makri S, Perrot S, Sarzi-Puttini P, Taylor A, Jones GT. EULAR revised recommendations for the management of fibromyalgia. Ann Rheum Dis. 2017;76(2):318-28. https://doi.org/10.1136/annrheumdis-2016-209724.

8 Woo HL, Ji HR, Pak YK, Lee H, Heo SJ, Lee JM, Park KS. The efficacy and safety of acupuncture in women with primary dysmenorrhea: a systematic review and meta-analysis. Medicine (Baltimore). 2018;97(23):e11007. https://doi.org/10.1097/MD.0000000000011007. PMid:29879061.

9 Luo X, Liu J, Li Q, Zhao J, Hao Q, Zhao L, Chen Y, Yin P, Li L, Liang F, Sun X. Acupuncture for treatment of knee osteoarthritis: a clinical practice guideline. J Evid Based Med. 2023;16(2):237-45. https://doi.org/10.1111/jebm.12526. PMid:36999342.

10 Kang WL, Xiao XJ, Fan R, Zhong DL, Li YX, She J, Li J, Feng Y, Jin RJ. Acupuncture for tension-type headache: a systematic review and meta-analysis of randomized controlled trials. Front Neurol. 2023;13:943495. https://doi.org/10.3389/fneur.2022.943495. PMid:37234488.

11 Chen X, Spaeth RB, Freeman SG, Scarborough DM, Hashmi JA, Wey HY, Egorova N, Vangel M, Mao J, Wasan AD, Edwards RR, Gollub RL, Kong J. The modulation effect of longitudinal acupuncture on resting state functional connectivity in knee osteoarthritis patients. Mol Pain. 2015;11:67. https://doi.org/10.1186/s12990-015-0071-9. PMid:26511911.

12 Egorova N, Goluub RL, Kong J. Repeated verum but not placebo acupuncture normalizes connectivity in brain regions dysregulated in chronic pain. Neuroimage Clin. 2015;9:430-5. https://doi.org/10.1016/j.nicl.2015.09.012. PMid:26594625.

13 Harris RE, Zubieta JK, Scott DJ, Napadow V, Gracely RH, Clauw DJ. Traditional Chinese acupuncture and placebo (sham) acupuncture are differentiated by their effects on mu-opioid receptors (MORs). Neuroimage. 2009;47(3):1077-85. https://doi.org/10.1016/j.neuroimage.2009.05.083. PMid:19501658.

14 Ahsin S, Saleem S, Bhatti AM, Iles RK, Aslam M. Clinical and endocrinological changes after electro-acupuncture treatment in patients with osteoarthritis of the knee. Pain. 2009;147(1-3):60-6. https://doi.org/10.1016/j.pain.2009.08.004. PMid:19766392.

15 Valera-Calero JA, Fernández-de-Las-Peñas C, Navarro-Santana MJ, Plaza-Manzano G. Efficacy of dry needling and acupuncture in patients with fibromyalgia: a systematic review and meta-analysis. Int J Environ Res Public Health. 2022;19(16):9904. https://doi.org/10.3390/ijerph19169904. PMid:36011540.

16 Baroncini A, Maffulli N, Eschweiler J, Molsberger F, Klimuch A, Migliorini F. Acupuncture in chronic aspecific low back pain: a Bayesian network meta-analysis. J Orthop Surg Res. 2022;17(1):319. https://doi.org/10.1186/s13018-022-03212-3. PMid:35725480.

17 Rizzo RRN, Cashin AG, Wand BM, Ferraro MC, Sharma S, Lee H, O’Hagan E, Maher CG, Furlan AD, van Tulder MW, McAuley JH. Non-pharmacological and non-surgical treatments for low back pain in adults: an overview of Cochrane reviews. Cochrane Database Syst Rev. 2025;3(3):CD014691. PMid:40139265.

18 Kollenburg L, Arnts H, Green A, Strauss I, Vissers K, Vinke S, Kurt E. The cingulum: a central hotspot for the battle against chronic intractable pain? Brain Commun. 2024;6(5):fcae368. https://doi.org/10.1093/braincomms/fcae368. PMid:39479369.

19 Roy M, Shohamy D, Daw N, Jepma M, Wimmer GE, Wager TD. Representation of aversive prediction errors in the human periaqueductal gray. Nat Neurosci. 2014;17(11):1607-12. https://doi.org/10.1038/nn.3832. PMid:25282614.

20 Hall JE. Tratado de fisiologia médica. 13. ed. Rio de Janeiro: Elsevier; 2017.

21 Cao B, Xu Q, Shi Y, Zhao R, Li H, Zheng J, Liu F, Wan Y, Wei B. Pathology of pain and its implications for therapeutic interventions. Signal Transduct Target Ther. 2024;9(1):155. https://doi.org/10.1038/s41392-024-01845-w. PMid:38851750.
 

Submitted date:
07/24/2025

Accepted date:
11/14/2025

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