The role of microglia in neuropathic pain: A systematic review of animal experiments

Background: Neuropathic pain develops from lesions or diseases that affect the peripheral or central somatosensory nervous system. External factors causing nervous system damage may induce neuropathic pain, which is often refractory and profoundly impairs patients’ quality of life and functional cap...

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Main Authors: Junyi Long, Guihua Tian, Ke He, Youxiang Su, Ziyao Wang, Liangqing Huang, Youmei Yao, Xinyi Li, Yi Lin
Format: Article
Language:English
Published: Elsevier 2025-08-01
Series:Brain Research Bulletin
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Online Access:http://www.sciencedirect.com/science/article/pii/S0361923025002229
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author Junyi Long
Guihua Tian
Ke He
Youxiang Su
Ziyao Wang
Liangqing Huang
Youmei Yao
Xinyi Li
Yi Lin
author_facet Junyi Long
Guihua Tian
Ke He
Youxiang Su
Ziyao Wang
Liangqing Huang
Youmei Yao
Xinyi Li
Yi Lin
author_sort Junyi Long
collection DOAJ
description Background: Neuropathic pain develops from lesions or diseases that affect the peripheral or central somatosensory nervous system. External factors causing nervous system damage may induce neuropathic pain, which is often refractory and profoundly impairs patients’ quality of life and functional capacity. Objective: This study aims to evaluate animal studies on neuropathic pain in the past three years to elucidate the mechanism of microglia in neuropathic pain and to provide a theoretical basis for clinical treatment. Methods: Literature searches were conducted through seven databases, including Web of Science, PubMed, EMBASE, China National Knowledge Infrastructure (CNKI), Wanfang Data, China Science and Technology Journal Database (VIPC), and SinoMed. The neuropathic pain model animals' pain indicators (thermal pain threshold, mechanical pain threshold), microglia-related findings, and related mechanism discoveries were extracted from the included studies. Results: A total of 24 animal studies were included in this study. All studies showed that microglia exhibited an activated state in animal neuropathic pain models established by different methods. Twenty studies demonstrated that microglial activation exacerbates neuropathic pain by driving neuroinflammatory cascades. However, four studies confirmed that microglia could alleviate pain through the M2 phenotype and the release of endogenous opioid peptides. Conclusion: The mediating effect of microglia on neuropathic pain is bidirectional. Pain-activated microglia do not necessarily exacerbate pain. Polarization toward the M2 phenotype or stimulation of endogenous opioid peptide release from microglia may attenuate pain. Overall, there are still many uncertainties about the mechanism of microglia in neuropathic pain. It is suggested to further study the neurobiological mechanism of this process to provide ideas for the design of future clinical trials. Registration: PROSPERO (ID: CRD42024599437)
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spelling doaj-art-fa4a632d2dc2494b92445ddcd8d51e602025-08-20T02:05:12ZengElsevierBrain Research Bulletin1873-27472025-08-0122811141010.1016/j.brainresbull.2025.111410The role of microglia in neuropathic pain: A systematic review of animal experimentsJunyi Long0Guihua Tian1Ke He2Youxiang Su3Ziyao Wang4Liangqing Huang5Youmei Yao6Xinyi Li7Yi Lin8Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing 100007, ChinaDongzhimen Hospital, Beijing University of Chinese Medicine, Beijing 100007, China; Corresponding author.Key Laboratory of Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing 100007, ChinaDongzhimen Hospital, Beijing University of Chinese Medicine, Beijing 100007, ChinaDongzhimen Hospital, Beijing University of Chinese Medicine, Beijing 100007, ChinaDongzhimen Hospital, Beijing University of Chinese Medicine, Beijing 100007, ChinaDongzhimen Hospital, Beijing University of Chinese Medicine, Beijing 100007, ChinaDepartment of Electronic Engineering, Tsinghua University, Beijing 100084, ChinaDongzhimen Hospital, Beijing University of Chinese Medicine, Beijing 100007, ChinaBackground: Neuropathic pain develops from lesions or diseases that affect the peripheral or central somatosensory nervous system. External factors causing nervous system damage may induce neuropathic pain, which is often refractory and profoundly impairs patients’ quality of life and functional capacity. Objective: This study aims to evaluate animal studies on neuropathic pain in the past three years to elucidate the mechanism of microglia in neuropathic pain and to provide a theoretical basis for clinical treatment. Methods: Literature searches were conducted through seven databases, including Web of Science, PubMed, EMBASE, China National Knowledge Infrastructure (CNKI), Wanfang Data, China Science and Technology Journal Database (VIPC), and SinoMed. The neuropathic pain model animals' pain indicators (thermal pain threshold, mechanical pain threshold), microglia-related findings, and related mechanism discoveries were extracted from the included studies. Results: A total of 24 animal studies were included in this study. All studies showed that microglia exhibited an activated state in animal neuropathic pain models established by different methods. Twenty studies demonstrated that microglial activation exacerbates neuropathic pain by driving neuroinflammatory cascades. However, four studies confirmed that microglia could alleviate pain through the M2 phenotype and the release of endogenous opioid peptides. Conclusion: The mediating effect of microglia on neuropathic pain is bidirectional. Pain-activated microglia do not necessarily exacerbate pain. Polarization toward the M2 phenotype or stimulation of endogenous opioid peptide release from microglia may attenuate pain. Overall, there are still many uncertainties about the mechanism of microglia in neuropathic pain. It is suggested to further study the neurobiological mechanism of this process to provide ideas for the design of future clinical trials. Registration: PROSPERO (ID: CRD42024599437)http://www.sciencedirect.com/science/article/pii/S0361923025002229Neuropathic painMicrogliaAnimal modelPreclinical studySystematic review
spellingShingle Junyi Long
Guihua Tian
Ke He
Youxiang Su
Ziyao Wang
Liangqing Huang
Youmei Yao
Xinyi Li
Yi Lin
The role of microglia in neuropathic pain: A systematic review of animal experiments
Brain Research Bulletin
Neuropathic pain
Microglia
Animal model
Preclinical study
Systematic review
title The role of microglia in neuropathic pain: A systematic review of animal experiments
title_full The role of microglia in neuropathic pain: A systematic review of animal experiments
title_fullStr The role of microglia in neuropathic pain: A systematic review of animal experiments
title_full_unstemmed The role of microglia in neuropathic pain: A systematic review of animal experiments
title_short The role of microglia in neuropathic pain: A systematic review of animal experiments
title_sort role of microglia in neuropathic pain a systematic review of animal experiments
topic Neuropathic pain
Microglia
Animal model
Preclinical study
Systematic review
url http://www.sciencedirect.com/science/article/pii/S0361923025002229
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