Electroacupuncture suppresses spinal nerve ligation-induced neuropathic pain via regulation of synaptic plasticity through upregulation of basic fibroblast growth factor expression

Efficacy of acupuncture in experimental intracerebral hemorrhage: a systematic review and meta-analysis

Objective

There is currently a lack of evidence in evidence-based medicine regarding acupuncture treatment for experimental intracerebral hemorrhage (ICH). The aim of this study was to systematically evaluate the efficacy of acupuncture treatment for experimental ICH based on neurological function scores and brain water content (BWC).

Methods

Eight mainstream Chinese and English databases were searched. Outcome measures included neurological function scores and BWC, and subgroup analysis was conducted based on study characteristics.

Results

A total of 32 studies were included. Meta-analysis results indicated that compared to the control group, the acupuncture group showed significant reductions in mNSS (MD = -3.16, p < 0.00001), Bederson score (MD = -0.99, p < 0.00001), Longa score (MD = -0.54, p < 0.0001), and brain water content (MD = -5.39, p < 0.00001). Subgroup analysis revealed that for mNSS, the autologous blood model (MD = -3.36) yielded better results than the collagenase model (MD = -0.92, p < 0.00001), and simple fixation (MD = -3.38) or no fixation (MD = -3.39) was superior to sham acupuncture (MD = -0.92, p < 0.00001). For BWC, the autologous blood model (MD = -7.73) outperformed the collagenase model (MD = -2.76, p < 0.00001), and GV20-GB7 (MD = -7.27) was more effective than other acupuncture points (MD = -2.92, p = 0.0006).

Conclusion

Acupuncture significantly improves neurological deficits and brain edema in experimental ICH. Acupuncture at GV20 - GB7 is more effective than at other points. These findings support further studies to translate acupuncture into clinical treatment for human ICH.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42023435584.

Acupuncture's long-term impact on depression prevention in primary dysmenorrhea: A 19-year follow-up of a Taiwan cohort with neuroimmune insights

BACKGROUND

Primary dysmenorrhea (PD) is a common gynecological condition causing depression. Acupuncture is an effective option for PD management but its effects on PD-associated depression remain unclear.

METHODS

A retrospective cohort study involving 35,099 propensity score-matched pairs of acupuncture users and non-users with PD was conducted using data from Taiwan's Longitudinal Generation Tracking Database 2000. Cox proportional hazard models were used to estimate depression risk, and bioinformatics analyses were performed to uncover underlying molecular mechanisms.

RESULTS

The risk of developing depression was reduced by 64 % in acupuncture users compared with non-acupuncture users during the 19-year follow-up period. The decrease was dose-dependent. Bioinformatics analyses identified 34 co-expressed targets for acupuncture, PD, and depression; and eight hub genes (coding for interleukin 6 and 1B, tumor necrosis factor, albumin, vascular endothelial growth factor A, C-reactive protein, prostaglandin-endoperoxide synthase 2, and brain-derived neurotrophic factor) potentially involved in the therapeutic effects of acupuncture. Several molecular pathways were found to be involved, including cytokine-cytokine receptor interaction, neuroactive ligand-receptor interaction, cyclic adenosine 3',5'-monophosphate signaling pathway, mitogen-activated protein kinase signaling pathway, serotonergic synapse, and estrogen signaling pathway.

LIMITATIONS

Bias in the selection of participants could have been introduced as a consequence of the retrospective nature of the study. Data were derived from a single national database, and acupuncture treatment details were unavailable.

CONCLUSION

Acupuncture may protect against the development of depression in patients with PD. This study provides insight into the potential molecular mechanisms underlying the therapeutic effects of acupuncture in PD management and depression prevention.

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.

Electroacupuncture Attenuates Neuropathic Pain in a Rat Model of Cervical Spondylotic Radiculopathy: Involvement of Spinal Cord Synaptic Plasticity

Purpose

Cervical spondylotic radiculopathy (CSR) is a common neurologic condition that causes chronic neck pain and motor functions, with neuropathic pain (NP) being the primary symptom. Although it has been established that electroacupuncture (EA) can yield an analgesic effect in clinics and synaptic plasticity plays a critical role in the development and maintenance of NP, the underlying mechanisms have not been fully elucidated. In this study, we explored the potential mechanisms underlying EA's effect on synaptic plasticity in CSR rat models.

Materials and Methods

The CSR rat model was established by spinal cord compression (SCC). Electroacupuncture stimulation was applied to LI4 (Hegu) and LR3 (Taichong) acupoints for 20 min once a day for 7 days. Pressure pain threshold (PPT) and mechanical pain threshold (MPT) were utilized to detect the pain response of rats. A gait score was used to evaluate the motor function of rats. Enzyme-linked immunosorbent assay (ELISA), Western blot (WB), immunohistochemistry (IHC), immunofluorescence (IF), and transmission electron microscopy (TEM) were performed to investigate the effects of EA.

Results

Our results showed that EA alleviated SCC-induced spontaneous pain and gait disturbance. ELISA showed that EA could decrease the concentration of pain mediators in the cervical nerve root. WB, IHC, and IF results showed that EA could downregulate the expression of synaptic proteins in spinal cord tissues and promote synaptic plasticity. TEM revealed that the EA could reverse the synaptic ultrastructural changes induced by CSR.

Conclusion

Our findings reveal that EA can inhibit SCC-induced NP by modulating the synaptic plasticity in the spinal cord and provide the foothold for the clinical treatment of CSR with EA.

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.

Knowledge Mapping of International Research on Acupuncture for Chronic Pain: A Bibliometric Analysis

INTRODUCTION

With the wide acceptance of acupuncture, many papers and guidelines recommend that acupuncture is effective for chronic pain (CP). In this study, we applied bibliometric methods to analyze the current research situation of acupuncture intervention in CP, to gain insight into the current situation and future development trend of this field.

MATERIAL AND METHODS

Science Citation Index Expanded was searched for publications related to acupuncture for CP between 1900 and 2022. VOSviewer, CiteSpace and Thomson Data Analyzer were used to analyze the annual publication, authors and cited authors and their countries (regions) and institutions, journals and cited journals, cited references, co-occurrence keywords, burst keywords, and the relevant centrality.

RESULTS

A total of 1968 papers were retrieved, the annual publications have shown a rapid growth trend in the recent 20 years. The USA (708) and the Kyung Hee University (31) were the most productive country and institution, respectively, while the USA (0.37) and University of Maryland (0.13) had the highest centrality. MacPherson, Hugh published the most papers in this field (29), and Vickers, A J were the most influential author (289 times cited). Journal of Alternative and Complementary Medicine was the most productive journal (92), whereas PAIN was the most influential one (4743 times cited). Breivik, H's (2006) paper had the most citation count (3025), while Furlan's (2005) paper had the highest centrality (0.23). The research focuses in this field mainly include pain, electroacupuncture, Low back pain, Systematic review, Randomized controlled trial etc. Researchers are currently paying more attention to the psychological problems caused by CP.

CONCLUSION

The research of acupuncture for CP will be further expanded. International cooperation of this research field needs to be further strengthened. More high-quality designed trials need to be conducted.

Electroacupuncture alleviates orofacial allodynia and anxiety-like behaviors by regulating synaptic plasticity of the CA1 hippocampal region in a mouse model of trigeminal neuralgia

Objective

Trigeminal neuralgia (TN), one of the most severe and debilitating chronic pain conditions, is often accompanied by mood disorders, such as anxiety and depression. Electroacupuncture (EA) is a characteristic therapy of Traditional Chinese Medicine with analgesic and anxiolytic effects. This study aimed to investigate whether EA ameliorates abnormal TN orofacial pain and anxiety-like behavior by altering synaptic plasticity in the hippocampus CA1.

Materials and methods

A mouse infraorbital nerve transection model (pT-ION) of neuropathic pain was established, and EA or sham EA was used to treat ipsilateral acupuncture points (GV20-Baihui and ST7-Xiaguan). Golgi-Cox staining and transmission electron microscopy (TEM) were administrated to observe the changes of synaptic plasticity in the hippocampus CA1.

Results

Stable and persistent orofacial allodynia and anxiety-like behaviors induced by pT-ION were related to changes in hippocampal synaptic plasticity. Golgi stainings showed a decrease in the density of dendritic spines, especially mushroom-type dendritic spines, in hippocampal CA1 neurons of pT-ION mice. TEM results showed that the density of synapses, membrane thickness of the postsynaptic density, and length of the synaptic active zone were decreased, whereas the width of the synaptic cleft was increased in pT-ION mice. EA attenuated pT-ION-induced orofacial allodynia and anxiety-like behaviors and effectively reversed the abnormal changes in dendritic spines and synapse of the hippocampal CA1 region.

Conclusion

EA modulates synaptic plasticity of hippocampal CA1 neurons, thereby reducing abnormal orofacial pain and anxiety-like behavior. This provides evidence for a TN treatment strategy.