Effect of electroacupuncture on the expression of P2 × 4, GABAA γ 2 and long-term potentiation in spinal cord of rats with neuropathic pain

Therapeutic efficacy of acupuncture point stimulation for stomach cancer pain: a systematic review and meta-analysis

Purpose

In recent years, traditional Chinese medicine has received widespread attention in the field of cancer pain treatment. This meta-analysis is the first to evaluate the effectiveness and safety of acupuncture point stimulation in the treatment of stomach cancer pain.

Methods

For this systematic review and meta-analysis, we searched PubMed, Web of Science, Cochrane Library, Embase, WANFANG, China National Knowledge Infrastructure (CNKI), and Chinese Journal of Science and Technology (VIP) databases as well as forward and backward citations to studies published between database creation to July 27, 2023. All randomized controlled trials (RCTs) on acupuncture point stimulation for the treatment of patients with stomach cancer pain were included without language restrictions. We assessed all outcome indicators of the included trials. The evidence from the randomized controlled trials was synthesized as the standardized mean difference (SMD) of symptom change. The quality of the evidence was assessed using the Cochrane Risk of Bias tool. This study is registered on PROSPERO under the number CRD42023457341.

Results

Eleven RCTs were included. The study included 768 patients, split into 2 groups: acupuncture point stimulation treatment group (n = 406), medication control group (n = 372). The results showed that treatment was more effective in the acupuncture point stimulation treatment group than in the medication control group (efficacy rate, RR = 1.63, 95% CI 1.37 to 1.94, p < 0.00001), decreasing in NRS score was greater in acupuncture point stimulation treatment group than in the medication control group (SMD = -1.30, 95% CI -1.96 to -0.63, p < 0.001).

Systematic Review Registration

https://clinicaltrials.gov/, identifier CRD42023457341.

Electroacupuncture suppresses neuronal ferroptosis to relieve chronic neuropathic pain

Growing evidence supports the analgesic efficacy of electroacupuncture (EA) in managing chronic neuropathic pain (NP) in both patients and NP models induced by peripheral nerve injury. However, the underlying mechanisms remain incompletely understood. Ferroptosis, a novel form of programmed cell death, has been found to be activated during NP development, while EA has shown potential in promoting neurological recovery following acute cerebral injury by targeting ferroptosis. In this study, to investigate the detailed mechanism underlying EA intervention on NP, male Sprague-Dawley rats with chronic constriction injury (CCI)-induced NP model received EA treatment at acupoints ST36 and GV20 for 14 days. Results demonstrated that EA effectively attenuated CCI-induced pain hypersensitivity and mitigated neuron damage and loss in the spinal cord of NP rats. Moreover, EA reversed the oxidative stress-mediated spinal ferroptosis phenotype by upregulating reduced expression of xCT, glutathione peroxidase 4 (GPX4), ferritin heavy chain (FTH1) and superoxide dismutase (SOD) levels, and downregulating increased expression of acyl-CoA synthetase long-chain family member 4 (ACSL4), malondialdehyde levels and iron overload. Furthermore, EA increased the immunofluorescence co-staining of GPX4 in neurons cells of the spinal cord of CCI rats. Mechanistic analysis unveiled that the inhibition of antioxidant pathway of Nrf2 signalling via its specific inhibitor, ML385, significantly countered EA's protective effect against neuronal ferroptosis in NP rats while marginally diminishing its analgesic effect. These findings suggest that EA treatment at acupoints ST36 and GV20 may protect against NP by inhibiting neuronal ferroptosis in the spinal cord, partially through the activation of Nrf2 signalling.

A Data Mining Study for Analysis of Acupoint Selection and Combinations in Acupuncture Treatment of Carpal Tunnel Syndrome

Background

Carpal tunnel syndrome (CTS) is the most prevalent upper limb compressive neuropathy. A considerable number of clinical trials and meta-analyses have provided evidence supporting the effectiveness of acupuncture in treating CTS. Nevertheless, the ideal choice of acupoints remains ambiguous.

Objective

A data mining analysis was conducted with the objective of determining the most effective acupoint combinations and selection for CTS.

Methods

A search was conducted across seven Chinese and English electronic bibliographic databases spanning from their inception to March 2023. Selected were clinical trials that evaluated the efficacy of acupuncture therapy for CTS, with or without randomised controlled methods. Data extraction mainly included acupoint prescriptions. Information such as first author, study design and study setting were also extracted. The principal outcomes comprised the clinical manifestations linked to CTS. Statistical descriptions were generated using Excel 2019. The analysis of association rules was conducted using SPSS Modeler 18.0. Using SPSS Statistics 26.0, exploratory factor analysis and cluster analysis were conducted.

Results

142 trials (including 86 RCTs and 56 non RCTs) were identified, and 193 groups of effective prescriptions involving 68 acupoints were extracted. The most frequently used acupoints were Da-ling (PC7), Nei-guan (PC6), He-gu (LI4), Wai-guan (TE5), and Yang-xi (LI5). The most frequently used meridians were the pericardial meridian and the large intestine meridian. The majority of special acupoints used were Five-shu points and Yuan-source points, with acupoints on the upper limbs being the most frequently used. The core acupoint groups were analyzed and 11 groups of association rules, 8 factors, and 5 effective cluster groups were obtained.

Conclusion

The evidence-based acupoint selection and combinations of acupuncture therapy for carpal tunnel syndrome were provided by the findings of this study.

The role of purinergic signaling in acupuncture-mediated relief of neuropathic and inflammatory pain

Acupuncture is a traditional medicinal practice in China that has been increasingly recognized in other countries in recent decades. Notably, several reports have demonstrated that acupuncture can effectively aid in pain management. However, the analgesic mechanisms through which acupuncture provides such benefits remain poorly understood. Purinergic signaling, which is mediated by purine nucleotides and purinergic receptors, has been proposed to play a central role in acupuncture analgesia. On the one hand, acupuncture affects the transmission of nociception by increasing adenosine triphosphate dephosphorylation and thereby decreasing downstream P2X3, P2X4, and P2X7 receptors signaling activity, regulating the levels of inflammatory factors, neurotrophic factors, and synapsin I. On the other hand, acupuncture exerts analgesic effects by promoting the production of adenosine, enhancing the expression of downstream adenosine A1 and A2A receptors, and regulating downstream inflammatory factors or synaptic plasticity. Together, this systematic overview of the field provides a sound, evidence-based foundation for future research focused on the application of acupuncture as a means of relieving pain.

The Role of the Brain-Derived Neurotrophic Factor in Chronic Pain: Links to Central Sensitization and Neuroinflammation

Chronic pain is sustained, in part, through the intricate process of central sensitization (CS), marked by maladaptive neuroplasticity and neuronal hyperexcitability within central pain pathways. Accumulating evidence suggests that CS is also driven by neuroinflammation in the peripheral and central nervous system. In any chronic disease, the search for perpetuating factors is crucial in identifying therapeutic targets and developing primary preventive strategies. The brain-derived neurotrophic factor (BDNF) emerges as a critical regulator of synaptic plasticity, serving as both a neurotransmitter and neuromodulator. Mounting evidence supports BDNF's pro-nociceptive role, spanning from its pain-sensitizing capacity across multiple levels of nociceptive pathways to its intricate involvement in CS and neuroinflammation. Moreover, consistently elevated BDNF levels are observed in various chronic pain disorders. To comprehensively understand the profound impact of BDNF in chronic pain, we delve into its key characteristics, focusing on its role in underlying molecular mechanisms contributing to chronic pain. Additionally, we also explore the potential utility of BDNF as an objective biomarker for chronic pain. This discussion encompasses emerging therapeutic approaches aimed at modulating BDNF expression, offering insights into addressing the intricate complexities of chronic pain.

Global research trends in acupuncture for cancer pain: A bibliometric analysis

BACKGROUND

In recent years, acupuncture has gained popularity in the management of cancer-related pain (CRP). This study aims to use bibliometric analysis to investigate the historical development, recent hotspots and research trends in this field.

METHODS

The Web of Science Core Collection database was selected as the data source for this study to retrieve and obtain literature related to acupuncture and CRP. Data analyses were performed with CiteSpace and VOSviewer to conduct the bibliometric analysis.

RESULTS

This bibliometric analysis was conducted from 2000 to 2022. A total of 664 publications were included in this work. The number of publications has steadily increased over the last 2 decades. The United States has the largest number of published articles (244 papers), while the People's Republic of China has the highest centrality (0.48). The primary research institutions were Memorial Sloan-Kettering Cancer Center, Kyung Hee University and Beijing University of Chinese Medicine. Mao Jun J. was the most prolific author, while Heather Greenlee was the most cited one. The most productive journal was Integrative Cancer Therapies. The most frequent keywords excluding the search subject were "electroacupuncture," "management," "quality of life," "breast cancer," "Aromatase inhibitor," "neuropathic pain," "mechanisms," and "protocol."

CONCLUSION

This study explored the application value of acupuncture in the management of CRP with bibliometric analysis, offering an intuitive understanding of this topic and revealing the hotspots and research trends.

Electroacupuncture ameliorates pain in cervical spondylotic radiculopathy rat by inhibiting the CaMKII/CREB/BDNF signaling pathway and regulating spinal synaptic plasticity

BACKGROUND

Central sensitization is one of the important mechanisms underlying neuropathic and radicular pain due to cervical spondylotic radiculopathy (CSR). Recent studies have shown that the calmodulin-dependent protein kinase II (CaMKII)/cAMP-response element binding protein (CREB)/brain-derived neurotrophic factor (BDNF) signaling pathway mediates central sensitization through its involvement in spinal cord synaptic plasticity. Our group has previously found that electroacupuncture (EA) has a good analgesic effect on CSR. However, the central analgesic mechanism of EA for CSR is not yet clear.

METHODS

The rats were randomly divided into Blank group, Sham-operated group, CSR group, and EA group. We prepared the CSR rat model using the fish wire extrusion method. The behavioral and mechanical pain thresholds of the rats in each group were measured 5 days after successful modeling and 7 days after the intervention. The first intervention was started 5 days after successful modeling, and the EA group was treated by acupuncture at the bilateral LI4 and LR3 points on the same side as one group, connected to a G6805-I electroacupuncture apparatus with continuous waves at 1.5 Hz. The remaining groups were not subjected to EA intervention. The treatment was administered once a day for 7 consecutive days and then executed. We used WB, immunofluorescence, and qRT-PCR to detect the expression of CaMKII/CREB/BDNF signaling pathway-related factors in the synaptic of rat spinal cord in each group.

RESULTS

EA improved pain threshold and motor function in CSR rats, inhibited the expression of BDNF, P-TrkB, CAMKII, and P-CREB in spinal cord synapses, reduced the expression of pain factor c-fos and postsynaptic membrane protein molecule neuroligin2, exerted a modulating effect on spinal cord synaptic plasticity in CSR rats, and suppressed the overactive synaptic efficacy.

CONCLUSION

EA mediates central sensitization and exerts analgesic effects on CSR by modulating spinal synaptic plasticity, which may be related to the inhibition of CaMKII/CREB/BDNF signaling pathway.

Effect of auricular acupressure combined with acupuncture for juvenile pseudomyopia

This retrospective study investigated the effect of auricular acupressure combined with acupuncture for juvenile pseudomyopia (JPM). In this retrospective study, we collected and analyzed a total of 66 eligible records of subjects with JPM. They were allocated into a treatment group (n = 33) and a control group (n = 33). All participants in both groups received auricular acupressure. Additionally, children in the treatment group also underwent acupuncture. The primary outcome was naked visual acuity (VA). It was performed using a standard E visual acuity chart. The secondary outcome was visual fatigue symptoms, as assessed by the College of Optometrists in Vision Development Quality of Life (COVD-QoL) questionnaire. All outcomes were analyzed before and after treatment. There were no significant differences regarding the naked VA and COVD-QoL scores before and after treatment between the 2 groups. However, there were significant differences regarding on naked VA (P < .01) and COVD-QoL scores (P < .01) within 2 groups compared before and after treatment. The findings of this study showed that both APP plus acupuncture and APP alone benefit children with JPM.

Electroacupuncture inhibits dendritic spine remodeling through the srGAP3-Rac1 signaling pathway in rats with SNL

Previous studies have shown that peripheral nerve injury can lead to abnormal dendritic spine remodeling in spinal dorsal horn neurons. Inhibition of abnormal dendritic spine remodeling can relieve neuropathic pain. Electroacupuncture (EA) has a beneficial effect on the treatment of neuropathic pain, but the specific mechanism remains unclear. Evidence has shown that slit-robo GTPase activating protein 3 (srGAP3) and Rho GTPase (Rac1) play very important roles in dendritic spine remodeling. Here, we used srGAP3 siRNA and Rac1 activator CN04 to confirm the relationship between SrGAP3 and Rac1 and their roles in improving neuropathic pain with EA. Spinal nerve ligation (SNL) was used as the experimental model, and thermal withdrawal latency (TWL), mechanical withdrawal threshold (MWT), Western blotting, immunohistochemistry and Golgi-Cox staining were used to examine changes in behavioral performance, protein expression and dendritic spines. More dendritic spines and higher expression levels of srGAP3 were found in the initial phase of neuropathic pain. During the maintenance phase, dendritic spines were more mature, which was consistent with lower expression levels of srGAP3 and higher expression levels of Rac1-GTP. EA during the maintenance phase reduced the density and maturity of dendritic spines of rats with SNL, increased the levels of srGAP3 and reduced the levels of Rac1-GTP, while srGAP3 siRNA and CN04 reversed the therapeutic effects of EA. These results suggest that dendritic spines have different manifestations in different stages of neuropathic pain and that EA may inhibit the abnormal dendritic spine remodeling by regulating the srGAP3/Rac1 signaling pathway to alleviate neuropathic pain.

The mechanistic basis for the effects of electroacupuncture on neuropathic pain within the central nervous system

Nociceptive signaling responses to painful stimuli are transmitted to the central nervous system (CNS) from the afferent nerves of the periphery through a series of neurotransmitters and associated signaling mechanisms. Electroacupuncture (EA) is a pain management strategy that is widely used, with clinical evidence suggesting that a frequency of 2-10 Hz is better able to suppress neuropathic pain in comparison to higher frequencies such as 100 Hz. While EA is widely recognized as a viable approach to alleviating neuralgia, the mechanistic basis underlying such analgesic activity remains poorly understood. The present review offers an overview of current research pertaining to the mechanisms whereby EA can alleviate neuropathic pain in the CNS, with a particular focus on the serotonin/norepinephrine, endogenous opioid, endogenous cannabinoid, amino acid neurotransmitter, and purinergic pathways. Moreover, the corresponding neurotransmitters, neuromodulatory compounds, neuropeptides, and associated receptors that shape these responses are discussed. Together, this review seeks to provide a robust foundation for further studies of the EA-mediated alleviation of neuropathic pain.

Role of nerve signal transduction and neuroimmune crosstalk in mediating the analgesic effects of acupuncture for neuropathic pain

Neurogenic pain rises because of nervous system damage or dysfunction and is the most difficult to treat among other pathological pains. Acupuncture has been reported as a great treatment option for neurogenic pain owing to its unlimited advantages. However, previous studies on the analgesic effects of acupuncture for NP were scattered and did not form a whole. In this study, we first comprehensively review the relevant basic articles on acupuncture for NP published in the last 5 years and summarize the analgesic mechanisms of acupuncture in terms of nerve signaling, neuro-immune crosstalk, and metabolic and oxidative stress regulation. Acupuncture inhibits the upstream excitatory system and suppresses neuronal transmission efficiency by downregulating glutamate, NMDA receptors, P2XR, SP, CGRP, and other neurotransmitters and receptors in the spinal cord, as well as plasma channels such as TRPV1, HCN. It can also activate the downstream pain inhibitory pathway by upregulating opioid peptide (β-endorphin), MOR receptors, GABA and GABA receptors, bi-directional regulating 5-hydroxytryptamine (5-HT) and its receptors (upregulate 5-HT 1A and downregulate 5-HT7R) and stimulating hypothalamic appetite-modifying neurons. Moreover, neuroinflammation in pain can be inhibited by acupuncture through inhibiting JAK2/STAT3, PI3K/mTOR pathways, down regulating chemokine receptor CX3CR1 on microglia and up regulating adenosine receptor A1Rs on astrocytes, inhibiting the activation of glia and reducing TNF-α and other inflammatory substances. Acupuncture also inhibits neuronal glucose metabolism by downregulating mPFC's GLUT-3 and promotes metabolic alterations of the brain, thus exerting an analgesic effect. In conclusion, the regulation of nerve signal transduction and neuroimmune crosstalk at the peripheral and central levels mediates the analgesic effects of acupuncture for neuropathic pain in an integrated manner. These findings provide a reliable basis for better clinical application of acupuncture in the management of neuropathic pain.

Effects of Acupuncture on Neuropathic Pain Induced by Spinal Cord Injury: A Systematic Review and Meta-Analysis

Introduction

Neuropathic pain is a commonly seen symptom and one of the most intractable comorbidities following spinal cord injury (SCI). Acupuncture has been widely used for neuropathic pain after SCI in clinical settings. There is no systematic review or meta‐analysis evaluating the efficacy of acupuncture in the treatment of SCI-induced neuropathic pain. Thus, this study aimed to conduct a systematic review and meta-analysis to assess the efficacy of acupuncture on SCI-induced neuropathic pain.

Methods

Seven databases were comprehensively searched, including PubMed, the Cochrane Library, the Web of Science, the China National Knowledge Infrastructure (CNKI), the Chinese Biomedical Literature Service System (SinoMed), the Wanfang Database, and the Chinese Scientific Journals Database (VIP) from their inception to 30 September 2021. Two independent reviewers evaluated the eligibility of the data retrieved based on the pre-established eligibility criteria and assessed the methodological quality of the included studies using the Cochrane Risk of Bias Tool. The outcome indexes in this study included the visual analogue scale, the numeric rating scale, the present pain intensity, and the pain region index. Sensitivity and subgroup analyses were also performed to specifically evaluate the intervention effects. In addition, publication bias was analyzed.

Results

Six randomized controlled trials (145 participants in the experimental groups and 141 participants in the control groups) were identified that evaluated the application of acupuncture for neuropathic pain after SCI and were included in this study. The results of our study revealed that acupuncture had a positive effect on the pain severity (standardized mean difference (SMD): −1.40, 95% confidence interval (CI): −2.23; −0.57), the present pain intensity (MD = −0.61, 95% CIs = −0.98; −0.23), and the pain region index (MD = −3.04, 95% CI = −3.98; −2.11). In addition, sensitivity analyses showed that these results were robust and stable. Subgroup analyses indicated that electroacupuncture (EA) had better effects on SCI-induced neuropathic pain. However, a publication bias was observed.

Conclusion

Available evidence appears to suggest that acupuncture may have a role in SCI-induced neuropathic pain management, but this remains to be determined.

Meta-Analysis on the Effects of Electric Acupuncture on Neural Functional Recovery and Related Pathways of Rats after Spinal Cord Injury

Background

Spinal cord injury (SCI) is a type of damage to the central nervous system (CNS) caused by various factors. The secondary injury of SCI is more complicated. Studies have found that electroacupuncture can help the recovery of nerve function during spinal cord injury. Therefore, this study explored the efficacy of electroacupuncture on complications after spinal cord injury through meta-analysis.

Methods

Relevant literatures published from January 2010 to March 2022 were searched with "Electric acupuncture, Spinal cord injury, Neural functional recovery, Spinal cord injury in rats, Neuronal Signaling" as search words. The risk of bias of included references was analyzed and assessed using RevMan 5.3 software and Stata software. Heterogeneity between studies was assessed using the Q-test and heterogeneity (I 2).

Results

There was no heterogeneity among the study groups. The comparison on the therapeutic effects of electroacupuncture and conventional therapy suggested that electroacupuncture was more effective for nerve recovery after spinal cord injury than conventional therapy. It can better improve the recovery of motor function after spinal cord injury in rats. On the other hand, SCI+EA had a good inhibitory effect on the expression of RhoA protein signal in rats and had a positive effect on the signal pathway. Discussion. The results of meta-analysis confirmed that electroacupuncture was more effective than conventional therapy in inhibiting pathways.

Electroacupuncture Alleviates Neuropathic Pain through Regulating miR-206-3p Targeting BDNF after CCI

Background

Electroacupuncture (EA) has benefits for neuropathic pain. However, the underlying mechanisms are still unknown. The current study explores the underlying mechanisms of EA in neuropathic pain of chronic constriction injury (CCI) rats. Material/Methods. Overall, 126 Sprague-Dawley (200-250 g) rats were divided into nine groups randomly: the sham-operated, CCI, CCI+EA, CCI+sham EA, CCI+NS, CCI+AAV-NC, CCI+AAV-miR-206-3p, CCI+EA+NS, and CCI+EA+AAV-miR-206-3p groups. The animals were sacrificed 14 days postsurgery. Mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) tests were used to determine differences in neurobehavioral manifestations. qPCR, western blotting, and immunofluorescence (IF) were carried out to detect the expression levels of miR-206-3p, BDNF, BAX/Bcl-2, TNF-α, and IL-6. Nissl staining was measured to observe morphological changes in neurons. Transmission electron microscopy (TEM) was employed to evaluate microscopic changes in dorsal horn synapses.

Results

Hyperalgesia was reduced markedly by EA in the CCI model. The expression level of miR-206-3p was elevated, whereas the expression levels of BDNF, BAX/Bcl-2, TNF-α, and IL-6 were decreased in EA-treated CCI rats. However, a miR-206-3p inhibitor partially abrogated the analgesic effect of EA and resulted in poor behavioral performance and the BDNF, BAX/Bcl-2, TNF-α, and IL-6 expression was elevated as well.

Conclusions

EA can relieve neuropathic pain by regulating the miR-206-3p/BDNF pathway, thus exerting anti-inflammatory and antiapoptotic effect.

Bibliometric and visualized analysis of electroacupuncture in the past 10 years

BACKGROUND

There are many studies that have interrogated the evolution and use of electroacupuncture (EA). We aimed to evaluate the research status, cooperation and development of EA in the past 10 years.

METHODS

We obtained data on the EA from the Web of Science core collection database. CiteSpace 5.7. R1 software was used to assess research cooperation through analysis of authors, institutions and countries. In addition, keyword cluster analysis, references and burst detection were analyzed to explore research hotspots and trends in the field of EA.

RESULTS

We included a total of 3019 citing literature and 78,235 cited literature for analysis. The data showed that there has been a rise in the global number of EA studies in the past decade. Besides, the data demonstrated that China has made outstanding contribution in the development of EA. Whereas there is inter-agency cooperation in China, there is less cooperation with other countries. In addition, we showed frequent use of keywords such as "expression", "stimulation", or "pain". Besides, neuroscience was the main research area, followed by general medicine and oncology. Furthermore, with the improved research methods and technologies, there is enhanced overall quality of the studies.

CONCLUSION

Taken together, our findings demonstrate a steady increase in the studies involving EA. However, the studies are unevenly distributed among countries and thus there is need for closer international cooperation.

Electroacupuncture at PC6 (Neiguan) Attenuates Angina Pectoris in Rats with Myocardial Ischemia-Reperfusion Injury Through Regulating the Alternative Splicing of the Major Inhibitory Neurotransmitter Receptor GABRG2

Angina pectoris is the most common manifestation of coronary heart disease, causing suffering in patients. Electroacupuncture at PC6 can effectively alleviate angina by regulating the expression of genes, whether the alternative splicing (AS) of genes is affected by acupuncture is still unknown. We established a rat model of myocardial ischemia-reperfusion by coronary artery ligation and confirmed electroacupuncture alleviated the abnormal discharge caused by angina pectoris measured in EMG electromyograms. Analysis of the GSE61840 dataset established that AS events were altered after I/R and regulated by electroacupuncture. I/R decreased the expression of splicing factor Nova1 while electroacupuncture rescued it. Further experiments in dorsal root ganglion cells showed Nova1 regulated the AS of the GABRG2, specifically on its exon 9 where an important phosphorylation site is present. In vivo, results also showed that electroacupuncture can restore AS of GABRG2. Our results proved that electroacupuncture alleviates angina results by regulating alternative splicing.

Effects of Electroacupuncture on Alleviating Prostatodynia and Inflammation in Rats with Chronic Nonbacterial Prostatitis

Purpose

Chronic prostatitis (CP) is a common urinary disease characterized by a complex sequence of symptoms including prostatodynia, which results in significant physical pain and mental burden to affected patients. Currently, CP has no standard treatment. Thus, physical therapy electroacupuncture (EA) which has been successful in treating several inflammation-related pain conditions was used to determine its effect on rats with CP.

Materials and Methods

Rats were castrated and treated with beta-estradiol for 28 days for CP modeling, and EA was initiated one week after. Following three weeks of treatment, pain-related behavioral testing, mechanical withdrawal threshold, and potential histopathological mechanisms were examined.

Results

EA treatment produced a significant antinociceptive effect, effectively increasing the pain threshold of CP rats, and the biochemical results revealed significantly lowered prostatic specific antigen levels. Histopathological results also demonstrated that EA exerted protective properties on prostate morphological changes, as well as decreased inflammation cytokines and oxidative stress molecular expressions in prostate tissue. Furthermore, EA alleviated microglial and astrocyte activation in the dorsal horn of the spinal cord, decreasing CXC motif ligand 1 expressions in activated spinal astrocytes.

Conclusion

In conclusion, it was demonstrated that EA alleviated CP-induced pain, which was partly achieved by the downregulation of inflammation, oxidative stress, and spinal cord glial activation.

Role of GABAAR in the Transition From Acute to Chronic Pain and the Analgesic Effect of Electroacupuncture on Hyperalgesic Priming Model Rats

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.