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

Needle-scalpel therapy inhibits the apoptosis of nucleus pulposus cells via the SDF-1/CXCR4 axis in a rat degenerative cervical intervertebral disc model

As a common disease, cervical spondylosis (CS) results from the degeneration of the cervical intervertebral disc. However, there are still no effective clinical strategies for the treatment of this disease. Needle-scalpel (Ns), a therapy guided by traditional Chinese medicine theory, alleviates intervertebral disc degradation and is widely used in the clinic to treat CS. Stromal cell-derived factor-1 (SDF-1) and its receptor CXC receptor 4 (CXCR4) in nucleus pulposus cells play an important role in CS onset and development. This study aimed to explore whether Ns can relieve pain and regulate the SDF-1/CXCR4 axis in nucleus pulposus cells to inhibit apoptosis, thereby delaying cervical intervertebral disc degradation in a rat model of CS. It was found that the Ns-treated groups exhibited higher mechanical allodynia scores than the model group, and H&E staining, MRI, and scanning electron microscopy revealed that Ns therapy inhibited intervertebral disc degeneration. Additionally, Ns therapy significantly inhibited increases in the RNA and protein expression levels of SDF-1 and CXCR4. Furthermore, these treatments alleviated the apoptosis of nucleus pulposus cells, which manifested as a decline in the proportion of apoptotic nucleus pulposus cells and inhibition of the decrease in the levels of Bcl-2/Bax. These findings indicated that Ns mitigated CS-induced pain, inhibited the apoptosis of nucleus pulposus cells, and alleviated intervertebral disc degeneration in CS rats. These effects may be mediated by specifically regulating the SDF-1/CXCR4 signaling axis. Based on these findings, we conclude that Ns might serve as a promising therapy for the treatment of CS.

Research Trends of Acupuncture Therapy for Chronic Pain-Related Depression or Anxiety from 2003 to 2023: A Bibliometric Analysis

Background

Chronic pain (CP) as a long-lasting stressor can often cause mood disorders, such as depression or anxiety. The comorbidity of CP and mood disorders poses challenges for treatment and increases healthcare costs. Acupuncture has emerged as a widely utilized approach to alleviate both CP and mood disorders. However, there is a lack of well-established bibliometric analyses in this area of research. Therefore, this study aimed to identify the current hotspots and research trends regarding the use of acupuncture for treating CP-related depression or anxiety.

Methods

We searched the Web of Science Core Collection spanning from 2003 to 2023 to identify relevant literature about the use of acupuncture for treating CP-related depression or anxiety. Bibliometric and visualization analyses were performed using CiteSpace 5.7.R5 and Vosviewer 1.6.19 software.

Results

A total of 254 articles published between 2003 and 2023 were included, revealing an upward trajectory with some fluctuations in publication numbers over the past two decades. China and the Beijing University of Chinese Medicine were the most productive country and institution in this field. Fang JQ and Vickers AJ ascended as the most prolific and influential authors, respectively. Trials was the journal with the highest number of publications, while Pain and BMJ-British Medical Journal exhibited the highest citation and centrality, respectively. "Acupuncture", "depression", and "chronic pain" were the top three keywords. The hotspots in this domain encompass types of chronic pain that predispose to negative mood, including fibromyalgia, irritable bowel syndrome (IBS), and neuropathic pain. Randomized controlled trials (RCTs), mechanisms, and evidence-based evaluations are the main research directions.

Conclusion

This study uses bibliometric techniques to analyze the research hotspots and forefronts of acupuncture as a therapeutic approach for CP-related depression or anxiety. Our objective is to provide researchers with valuable references and identify research focal points for future investigations.

Electroacupuncture exerts prolonged analgesic and neuroprotective effects in a persistent dental pain model induced by multiple dental pulp injuries: GABAergic interneurons-astrocytes interaction

Pain within the trigeminal system, particularly dental pain, is poorly understood. This study aimed to determine whether single or multiple dental pulp injuries induce persistent pain, its association with trigeminal central nociceptive pathways and whether electroacupuncture (EA) provides prolonged analgesic and neuroprotective effects in a persistent dental pain model. Models of single dental pulp injury (SDPI) and multiple dental pulp injuries (MDPI) were used to induce trigeminal neuropathic pain. The signs of dental pain-related behavior were assessed using the mechanical head withdrawal threshold (HWT). Immunofluorescence and western blot protocols were used to monitor astrocyte activation, changes in apoptosis-related proteins, and GABAergic interneuron plasticity. SDPI mice exhibited an initial marked decrease in HWT from days one to 14, followed by progressive recovery from days 21 to 42. From days 49 to 70, the HWT increased and returned to the control values. In contrast, MDPI mice showed a persistent decrease in HWT from days one to 70. MDPI increased glial fibrillary acidic protein (GFAP) and decreased glutamine synthetase (GS) and glutamate transporter-1 (GLT1) expression in the Vi/Vc transition zone of the brainstem on day 70, whereas no changes in astrocytic markers were observed on day 70 after SDPI. Increased expression of cleaved cysteine-aspartic protease-3 (cleaved caspase-3) and Bcl-2-associated X protein (Bax), along with decreased B-cell lymphoma/leukemia 2 (Bcl-2), were observed at day 70 after MDPI but not after SDPI. The downregulation of glutamic acid decarboxylase (GAD65) expression was observed on day 70 only after MDPI. The effects of MDPI-induced lower HWT from days one to 70 were attenuated by 12 sessions of EA treatment (days one to 21 after MDPI). Changes in astrocytic GFAP, GS, and GLT-1, along with cleaved caspase-3, Bax, Bcl-2, and GAD65 expression observed 70 days after MDPI, were reversed by EA treatment. The results suggest that persistent dental pain in mice was induced by MDPI but not by SDPI. This effect was associated with trigeminal GABAergic interneuron plasticity along with morphological and functional changes in astrocytes. EA exerts prolonged analgesic and neuroprotective effects that might be associated with the modulation of neuron-glia crosstalk mechanisms.

Brain nuclei and neural circuits in neuropathic pain and brain modulation mechanisms of acupuncture: a review on animal-based experimental research

Neuropathic pain (NP) is known to be associated with abnormal changes in specific brain regions, but the complex neural network behind it is vast and complex and lacks a systematic summary. With the help of various animal models of NP, a literature search on NP brain regions and circuits revealed that the related brain nuclei included the periaqueductal gray (PAG), lateral habenula (LHb), medial prefrontal cortex (mPFC), and anterior cingulate cortex (ACC); the related brain circuits included the PAG-LHb and mPFC-ACC. Moreover, acupuncture and injurious information can affect different brain regions and influence brain functions via multiple aspects to play an analgesic role and improve synaptic plasticity by regulating the morphology and structure of brain synapses and the expression of synapse-related proteins; maintain the balance of excitatory and inhibitory neurons by regulating the secretion of glutamate, γ-aminobutyric acid, 5-hydroxytryptamine, and other neurotransmitters and receptors in the brain tissues; inhibit the overactivation of glial cells and reduce the release of pro-inflammatory mediators such as interleukins to reduce neuroinflammation in brain regions; maintain homeostasis of glucose metabolism and regulate the metabolic connections in the brain; and play a role in analgesia through the mediation of signaling pathways and signal transduction molecules. These factors help to deepen the understanding of NP brain circuits and the brain mechanisms of acupuncture analgesia.

Curcumin alleviates orofacial allodynia and improves cognitive impairment via regulating hippocampal synaptic plasticity in a mouse model of trigeminal neuralgia

OBJECTIVE

Cognitive impairment, one of the most prevalent complications of trigeminal neuralgia, is troubling for patients and clinicians due to limited therapeutic options. Curcumin shows antinociception and neuroprotection pharmacologically, suggesting that it may have therapeutic effect on this complication. This study aimed to investigate whether curcumin alleviates orofacial allodynia and improves cognitive impairment by regulating hippocampal CA1 region synaptic plasticity in trigeminal neuralgia.

METHODS

A mouse model of trigeminal neuralgia was established by partially transecting the infraorbital nerve (pT-ION). Curcumin was administered by gavage twice daily for 14 days. Nociceptive thresholds were measured using the von Frey and acetone test, and the cognitive functions were evaluated using the Morris water maze test. Dendritic spines and synaptic ultrastructures in the hippocampal CA1 area were observed by Golgi staining and transmission electron microscopy.

RESULTS

Curcumin intervention increased the mechanical and cold pain thresholds of models. It decreased the escape latency and distance to the platform and increased the number of platform crossings and dwell time in the target quadrant of models, and improved spatial learning and memory deficits. Furthermore, it partially restored the disorder of the density and proportion of dendritic spines and the abnormal density and structure of synapses in the hippocampal CA1 region of models.

CONCLUSION

Curcumin alleviates abnormal orofacial pain and cognitive impairment in pT-ION mice by a mechanism that may be related to the synaptic plasticity of hippocampal CA1, suggesting that curcumin is a potential strategy for repairing cognitive dysfunction under long-term neuropathic pain conditions.

Electroacupuncture Alleviates Lung Injury in CpG1826-Challenged Mice via Modulating CD39-NLRP3 Pathway

PURPOSE

Cytokine storm secondary lung injury (CSSLI) is the leading death cause in COVID-19 virus infection, and CD39-dominated purinergic brake drives NLRP3 inflammasome activation and pyroptosis, which plays a crucial role in the pathogenesis of CSSLI. Though electroacupuncture (EA) can alleviate lung injury caused by a variety of inducers, its effect on CSSLI and the underlying mechanism needs further investigation.

METHODS

We established a widely recognized CSSLI mice model with CpG1826 (CpG), a TLR-9 agonist agent. Luminex liquid chip was employed to detect serum levels of 12 cytokines/chemokines to evaluate cytokine storm formation. H+E staining and transmission electron microscope were applied to examine pulmonary pathological injury and alveolar macrophage structure, respectively. IL-1β, IL-18, IL-1α, and HMGB-1 in BAL fluid were determined by ELISA kits. mRNA and protein levels of lung CD39 and NLRP3 were assessed by qRT-PCR and Western blotting. An in vitro model was also established by incubating PMA-differentiated THP-1 cells with serum samples obtained from relevant group of mice.

RESULTS

Repeated CpG induced CSSLI together with the elevation of 11 cytokines/chemokines including GM-CSF, IL-16, IL-1α, MCP-1, IL-2, IL-10, CCL3, IL-1β, TNF-α, IL-6, and IL-17A, though not IFN-γ, which was reduced by EA pretreatment to a different extent. EA also alleviated lung injury and recovered lung macrophage structure. Moreover, CpG enhanced IL-1β and IL-18 level in BAL fluid, promoted NLRP3, while suppressing CD39 expression in lung, all of which were reversed by EA pretreatment. Of note, EA failed to further decrease BAL fluid IL-1β, IL-18, IL-1α, and HMGB-1 levels when A438079, a selective inhibitor of P2X7, was administered. However, both CD39 and NLRP3 are dispensable for EA decreasing multi-cytokine secretion in serum-incubated and CpG-stimulated THP-1 cells. Taken together, EA alleviated CSSLI in CpG-challenged mice by regulating the CD39-NLRP3 pathway in a P2X7-dependent way.

CONCLUSION

EA demonstrated potential to be applied in COVID-19 treatment.

Evaluation of anxiety disorder in patients with trigeminal neuralgia

BACKGROUND

The aim of this cross-sectional study was to evaluate the relationship between anxiety levels and severity of trigeminal neuralgia (TN) disorder's chronic orofacial pain during 2019-2020 in Shiraz Dental Faculty.

METHODS

In this study, patients with TN disorder who were referred to the Oral Medicine Department of Shiraz Dental Faculty were evaluated. Individuals were selected based on convenience sampling. Finally, 47 patients with TN were recruited in this study. Satisfaction with treatment was recorded based on controlling the patient's pain, age, sex, and frequency of recurrence, and data were analyzed using SPSS18. The Chi-square test was used to compare the final results. A reliability of more than 95% was considered significant (P < 0.05).

RESULTS

According to the results, the mean ages of participants with TN and control groups were 56.89 ± 10.93 and 37.12 ± 9.55, respectively. The mean value of participants' age was significantly different between the two evaluated groups (P < 0.0001). The anxiety of patients with TN was significantly higher than the healthy control group (P < 0.0001). The mean level of anxiety in patients with TN and also in healthy controls was not significantly different among men and women (P > 0.05). The mean level of anxiety of men and women in TN group was significantly higher than the healthy control women (P = 0.001). The mean levels of anxiety between different age ranges in patients with TN and healthy controls were not different in both evaluated groups (P > 0.05). Patients with TN in different age ranges had higher level of anxiety than healthy controls (P < 0.05).

CONCLUSION

Patients with TN had significantly higher level of anxiety than healthy participants.

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 treatment ameliorates depressive-like behavior and cognitive dysfunction via CB1R dependent mitochondria biogenesis after experimental global cerebral ischemic stroke

Introduction

This study aimed to identify the effect of electroacupuncture (EA) treatment on post-stroke depression (PSD) and explore whether cannabinoid receptor 1 (CB1R)-mediated mitochondrial biogenesis accounts for the treatment effect of EA.

Methods

The PSD mouse model was induced by a consecutive 14-day chronic unpredictable stress operation after 7 days of recovery from the bilateral common carotid artery occlusion surgery. Either EA treatment or sham stimulation was performed for 14 consecutive days from Day 7 after the BCCAO operation. Subjects’ PSD-like behaviors were tested via open field test, sucrose preference test, novelty suppressed feeding test, tail suspension test, and forced swim test, and subjects’ cognitive function was examined using Y-maze and novelty object recognition test. In addition, the levels of CB1R, mitochondrial biogenesis-related proteins (nuclear transcription factor 1, NRF1; mitochondrial transcription factor A, TFAM), proteins related to mitochondrial function (Cytochrome C, Cyto C; AIF, COX IV), and mitochondrial DNA were measured. To elucidate the role of CB1R in EA treatment, CB1R antagonists AM251 and CB1R-shRNA were given to mice before EA treatment. Likewise, subjects’ depressive-like behaviors, cognitive function, mitochondrial function, and mitochondrial biogenesis were examined after the PSD procedure.

Results

It has been showed that EA successfully ameliorated depressive-like behaviors, improved cognitive dysfunctions, and upregulated CB1R, NRF1 and TFAM expressions. However, the supplementation of AM251 and CB1R-shRNA blocked the antidepressant-like effects generated by EA, and EA failed to improve cognitive dysfunction, upregulate CB1R protein expression, and increase mitochondrial function and biogenesis.

Conclusion

Altogether, these results indicated that EA ameliorated PSD-like behaviors in mice, improved cognitive dysfunctions after PSD, and promoted mitochondrial biogenesis by activating CB1R, a novel mechanism underlying EA’s antidepressant-like effects in treating PSD.