Role of Sigma-1 Receptor/p38 MAPK Inhibition in Acupoint Catgut Embedding-Mediated Analgesic Effects in Complete Freund's Adjuvant-Induced Inflammatory Pain

Short-chain fatty acids mitigate Methamphetamine-induced hepatic injuries in a Sigma-1 receptor-dependent manner

Methamphetamine (Meth) is a potent psychostimulant with well-established hepatotoxicity. Gut microbiota-derived short-chain fatty acids (SCFAs) have been reported to yield beneficial effects on the liver. In this study, we aim to further reveal the mechanisms of Meth-induced hepatic injuries and investigate the potential protective effects of SCFAs. Herein, mice were intraperitoneally injected with 15 mg/kg Meth to induce hepatic injuries. The composition of fecal microbiota and SCFAs was profiled using 16 S rRNA sequencing and Gas Chromatography/Mass Spectrometry (GC/MS) analysis, respectively. Subsequently, SCFAs supplementation was performed to evaluate the protective effects against hepatic injuries. Additionally, Sigma-1 receptor knockout (S1R-/-) mice and fluvoxamine (Flu), an agonist of S1R, were introduced to investigate the mechanisms underlying the protective effects of SCFAs. Our results showed that Meth activated S1R and induced hepatic autophagy, inflammation, and oxidative stress by stimulating the MAPK/ERK pathway. Meanwhile, Meth disrupted SCFAs product-related microbiota, leading to a reduction in fecal SCFAs (especially Acetic acid and Propanoic acid). Accompanied by the optimization of gut microbiota, SCFAs supplementation normalized S1R expression and ameliorated Meth-induced hepatic injuries by repressing the MAPK/ERK pathway. Effectively, S1R knockout repressed Meth-induced activation of the MAPK/ERK pathway and further ameliorated hepatic injuries. Finally, the overexpression of S1R stimulated the MAPK/ERK pathway and yielded comparable adverse phenotypes to Meth administration. These findings suggest that Meth-induced hepatic injuries relied on the activation of S1R, which could be alleviated by SCFAs supplementation. Our study confirms the crucial role of S1R in Meth-induced hepatic injuries for the first time and provides a potential preemptive therapy.

A comprehensive practical review of acupoint embedding as a semi-permanent acupuncture: A mini review

Since ancient times, acupuncture has been utilized in the treatment of lots of diseases, as a part of Traditional Chinese Medicine. Acupoint embedding (AEM) therapy, known as catgut embedding, is a development of acupuncture that consists of inserting catgut or surgical threads into specific acupoints to produce continuous acupoint stimulation based on the theory of Traditional Chinese Medicine. The remaining thread in the acupoint works as a semi-permanent acupuncture needle that results in decreasing the total time of the treatment which is required for continuous manual acupuncture sessions and increasing the treatment efficacy and patients' satisfaction. In each session of AEM about twenty 1 to 2 cm-long threads-natural origin, synthetic polymer, or bioactive threads-will be inserted at the target acupoints and this process will be repeated every 3 to 4 weeks. Indications of AEM are somehow similar to manual acupuncture including obesity, pain, musculoskeletal inflammations, infertility, etc, and it cannot be performed on pregnant women and pediatrics. AEM demonstrates its therapeutic effects via modulating immune system function, alleviating body inflammatory conditions, affecting the neurohormonal system, and other mechanisms. Subcutaneous indurations, redness, bleeding, hematoma, and bruising are some adverse events reported following the AEM. In conclusion, the scientific literature suggests that AEM is a relatively safe and convenient therapy if performed by a professional skilled practitioner.

Catgut embedding in acupoints combined with repetitive transcranial magnetic stimulation for the treatment of postmenopausal osteoporosis: study protocol for a randomized clinical trial

Background

To date, the clinical modulation for bone metabolism based on the neuro-bone mass regulation theory is still not popular. The stimulation of nerve systems to explore novel treatments for Postmenopausal osteoporosis (PMOP) is urgent and significant. Preliminary research results suggested that changes brain function and structure may play a crucial role in bone metabolism with PMOP. Thus, we set up a clinical trial to investigate the effect of the combination of repetitive transcranial magnetic stimulation (rTMS) and catgut embedding in acupoints (CEA) for PMOP and to elucidate the central mechanism of this neural stimulation in regulating bone metabolism.

Method

This trial is a prospective and randomized controlled trial. 96 PMOP participants will be randomized in a 1:1:1 ratio into a CEA group, an rTMS group, or a combined one. Participants will receive CEA, rTMS, or combined therapy for 3 months with 8 weeks of follow-up. The primary outcomes will be the changes in Bone Mineral Density scores, total efficiency of Chinese Medicine Symptoms before and after treatment. Secondary outcomes include the McGill Pain Questionnaire Short-Form, Osteoporosis Symptom Score, Mini-Mental State Examination, and Beck Depression Inventory-II. The leptin, leptin receptor, and norepinephrine levels of peripheral blood must be measured before and after treatment. Adverse events that occur during the trial will be recorded.

Discussion

CEA achieves brain-bone mass regulation through the bottom-up way of peripheral-central while rTMS achieves it through the top-down stimulation of central-peripheral. CEA combined with rTMS can stimulate the peripheral-central at the same time and promote peripheral bone mass formation. The combination of CEA and rTMS may play a coordinating, synergistic, and side-effect-reducing role, which is of great clinical significance in exploring better treatment options for PMOP.Clinical trial registration: https://www.chictr.org.cn/, identifier ChiCTR2300073863.

Acupuncture alleviates CUMS-induced depression-like behaviors of rats by regulating oxidative stress, neuroinflammation and ferroptosis

BACKGROUND

The treatment of depression with acupuncture has been documented. The mechanism behind acupuncture's curative and preventative effects is still unknown.

METHODS

The current study examined the effects of acupuncture on depression-like behaviors in a rat model of chronic unpredictable mild stress (CUMS), while also exploring its potential mechanisms. A total of six groups of rats were randomly assigned: control, CUMS, acupuncture, fluoxetine, acupoint catgut embedding and sham acupoint catgut embedding. Fluoxetine (2.1 mg/kg) and acupoint catgut embedding were used for comparative research to acupuncture. The modelling evaluation is measured by body weight and behavior tests. Western blotting and reverse transcription-polymerase chain reaction were used to detect the proteins and mRNA expression of Silent information regulator 1 (Sirt1)/ nuclear factor-erythroid 2-related factor 2 (Nrf2)/ heme oxygenase-1 (HO-1)/ Glutathione peroxidase 4 (GPX4) pathway in the hippocampus. The expression of oxidative stress (OS)-related proteins and inflammatory cytokines in the serum was detected with ELISA. Immunofluorescence showed microglia and astrocytes activity in the hippocampus.

RESULTS

Acupuncture and fluoxetine could alleviate CUMS-induced depression-like behaviors. Acupuncture was also found to effectively reverse the levels of MDA, SOD, GSH, GSH-PX and T-AOC, IL-1β, IL-6 and TNF-α in the serum of CUMS-induced rats. Rats with CUMS showed decreased levels of Sirt1, Nrf2, HO-1 and GPX4 in the hippocampus, while acupuncture treatment could partly reverse the diminished effects. In addition, acupuncture treatment significantly reduced the activation of hippocampal microglia and astrocytes in CUMS-induced rats.

CONCLUSION

The study's findings indicate that acupuncture has the potential to mitigate depression-like behaviors in rats induced with CUMS by mitigating OS and reducing neuroinflammation.

Acupoint catgut embedding for chronic non-specific low back pain: A protocol of randomized controlled trial

Chronic non-specific low back pain (CNLBP) is one of the leading causes of disability worldwide. Acupoint embedding (ACE) is widely used in China for the treatment of chronic non-specific low back pain, but there are no rigorous randomized controlled trials (RCTs) to confirm the effectiveness and safety of ACE for chronic non-specific low back pain. In this study, we design a single-center, single-blind, prospective RCT, with the aim of evaluating the efficacy and safety of ACE for CNLBP. 82 participants with CNLBP will be randomized in a 1:1 ratio into an ACE group and a sham ACE group. Participants will receive either ACE treatment or sham ACE treatment at once every 2 weeks, for an 8-week period, and followed by 6 months of follow-up. The primary outcome will be the change in visual analog scale (VAS) scores before and after treatment. Secondary outcomes will include the Oswestry Disability Index (ODI), the Roland Morris Disability Questionnaire (RMDQ) and the Short Form 36-Health Survey (SF-36). Adverse events that occur during the course of the trial will be recorded. Data will be analyzed according to a predefined statistical analysis plan. This study was approved by the medical ethics committee of Guangzhou Panyu Hospital of Chinese Medicine (202230). Written informed consent from patients is required. This trial is registered in the Chinese Clinical Trial Registry (ChiCTR2200059245). Trial results will be published in a peer-reviewed academic journal.

Clinical trial registration

https://www.chictr.org.cn, identifier ChiCTR2200059245.

EA participates in pain transition through regulating KCC2 expression by BDNF-TrkB in the spinal cord dorsal horn of male rats

The pathogenesis of chronic pain is complex and poorly treated, seriously affecting the quality of life of patients. Electroacupuncture (EA) relieves pain by preventing the transition of acute pain into chronic pain, but its mechanism of action is still unclear. Here, we aimed to investigate whether EA can inhibit pain transition by increasing KCC2 expression via BDNF-TrkB. We used hyperalgesic priming (HP) model to investigate the potential central mechanisms of EA intervention on pain transition. HP model male rats showed significant and persistent mechanically abnormal pain. Brain derived neurotrophic factor (BDNF) expression and Tropomyosin receptor kinase B (TrkB) phosphorylation were upregulated in the affected spinal cord dorsal horn (SCDH) of HP model rats, accompanied by K⁺-Cl^-- Cotransporter-2 (KCC2) expression was down-regulated. EA significantly increased the mechanical pain threshold in HP model male rats and decreased BDNF and p-TrkB overexpression and upregulated KCC2 expression. Blockade of BDNF with BDNF neutralizing antibody attenuated mechanical abnormal pain in HP rats. Finally, administration of exogenous BDNF by pharmacological methods reversed the EA-induced resistance to abnormal pain. In all, these results suggest that BDNF-TrkB contributes to mechanical abnormal pain in HP model rats and that EA ameliorates mechanical abnormal pain through upregulation of KCC2 by BDNF-TrkB in SCDH. Our study further supports EA as an effective treatment to prevent the transition of acute pain into chronic pain.

Identification of the key ferroptosis-related genes involved in sepsis progression and experimental validation in vivo

Background: Ferroptosis has a vital role in sepsis, but the mechanism is not known. Understanding the mechanism of ferroptosis during sepsis will aid in developing improved therapeutic strategies.

Methods: We used the Gene Expression Omnibus database and FerrDb database to obtain ferroptosis-related differentially expressed genes (DEGs) between sepsis patients and healthy volunteers (HVs). Analyses of PPI networks, functional enrichment, as well as use of the MCODE algorithm were used to identify key ferroptosis-related DEGs. Expression of key ferroptosis-related DEGs was verified using: GSE57065 and GSE65682 datasets; rats in which ferroptosis was induced with erastin; sepsis-induced acute lung injury (siALI) rats. The effects of acupoint catgut embedding (ACE) on ferroptosis and expression of key ferroptosis-related DEGs in the lungs of siALI rats were also observed. A Cox proportional hazard model was used to verify the effect of key ferroptosis-related DEGs on the survival of sepsis patients. Cytoscape was used to construct ceRNA networks and gene–transcription factor networks.

Results: Between sepsis patients and HVs, we identified 33 ferroptosis-related DEGs. According to analyses of PPI networks and the MCODE algorithm, we obtained four modules, of which the most significant module contained nine ferroptosis-related DEGs. Functional-enrichment analyses showed that four of the nine DEGs were enriched in the MAPK signaling pathway: MAPK14, VEGFA, TGFBR1, and DUSP1. We verified expression of these four genes in GSE57065 and GSE65682 datasets and ferroptosis rats. In addition, expression of these four genes and that of the oxidative-stress indicators GSSG and MDA was upregulated, and glutathione peroxidase-4 (GPX4) expression was downregulated, in siALI rats, but ACE reversed these changes. The Cox proportional hazard model showed that survival of sepsis patients in the high-risk group was shorter than that in the low-risk group. We found that the XIST−hsa-let-7b-5p−TGFBR1/DUSP1 ceRNA network and transcription factor E2F1 may be important regulators of these four DEGs.

Conclusion: Our results suggest that MAPK14, VEGFA, TGFBR1, and DUSP1 may be key regulatory targets of ferroptosis in sepsis, and that ACE pretreatment may be antioxidant treatment for sepsis and alleviate ferroptosis. These findings provide a basis for further ferroptosis-related study in sepsis and provide new targets for its treatment.

Sigma-1 receptor activity in primary sensory neurons is a critical driver of neuropathic pain

The Sigma-1 receptor (σ1R) is highly expressed in the primary sensory neurons (PSNs) that are the critical site of initiation and maintenance of pain following peripheral nerve injury. By immunoblot and immunohistochemistry, we observed increased expression of both σ1R and σ1R-binding immunoglobulin protein (BiP) in the lumbar (L) dorsal root ganglia (DRG) ipsilateral to painful neuropathy induced by spared nerve injury (SNI). To evaluate the therapeutic potential of PSN-targeted σ1R inhibition at a selected segmental level, we designed a recombinant adeno-associated viral (AAV) vector expressing a small hairpin RNA (shRNA) against rat σ1R. Injection of this vector into the L4/L5 DRGs induced downregulation of σ1R in DRG neurons of all size groups, while expression of BiP was not affected. This was accompanied by attenuation of SNI-induced cutaneous mechanical and thermal hypersensitivity. Whole-cell current-clamp recordings of dissociated neurons showed that knockdown of σ1R suppressed neuronal excitability, suggesting that σ1R silencing attenuates pain by reversal of injury-induced neuronal hyperexcitability. These findings support a critical role of σ1R in modulating PSN nociceptive functions, and that the nerve injury-induced elevated σ1R activity in the PSNs can be a significant driver of neuropathic pain. Further understanding the role of PSN-σ1R in pain pathology may open routes to exploit this system for DRG-targeted pain therapy.

Thread Embedded Acupuncture for Non-Specific Posterior Neck Pain: A PRISMA-Compliant Protocol for Systematic Review and Meta-Analysis

Purpose

The prevalence of non-specific posterior neck pain (NPNP) has been increasing yearly. There are several treatments for NPNP, but in this review, we will focus on thread-embedded acupuncture (TEA). TEA is used in the Republic of Korea, Taiwan, and China for managing musculoskeletal diseases, obesity, and sequelae of facial palsy. However, there is insufficient evidence on its effectiveness and safety. This study aims to assess the efficacy and safety of TEA for NPNP.

Methods

We will search the following nine electronic databases, from their inception to May 2020: MEDLINE, Embase, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure, Citation Information by the National Information infrastructure, Korean Studies Information Service System, National Digital Science Library, Oriental Medicine Advanced Searching Integrated System, and Research Information Service System. Only randomized controlled trials of TEA for NPNP will be included. The methodological quality of the included trials will be assessed using the Cochrane risk-of bias tool. To conduct the meta-analysis, the risk ratio and mean difference with the 95% confidence interval will be used. Sensitivity analyses will be conducted based on this protocol.

Results

The results of this study will be submitted to a peer-reviewed journal for publication.

Conclusion

The results of this study would provide the evidence of whether TEA can be effective for treating NPNP.

Registration Number

PROSPERO CRD42020188346.

Effect of acupoint catgut embedding in chronic fatigue syndrome patients: A protocol for systematic review and meta-analysis

BACKGROUND

Chronic fatigue syndrome (CFS) is a relatively complex and disabling illness with a substantial economic burden and functional impairment. Until now, many CFS patients lack appropriate healthcare. Acupoint catgut embedding is an effective and emerging alternative therapy for CFE. With this research, we endeavor to investigate the effect and safety of ACE for CFS.

METHODS

Eight databases will be searched from inception to December 2020: PubMed, EMBASE, The Cochrane Library, Web of Science, China National Knowledge Infrastructure, Chinese Biomedical Literature Database, Chong-Qing VIP database, and Wan-fang database. We regard studies as eligible for inclusion if they were RCTs done in CFS patients, compare acupoint catgut embedding to another treatment strategy, and report fatigue changes at the end of the intervention period. Two independent reviewers complete the study selection, data extraction, and the risk of bias assessment. We assess pooled data using a random-effects model through Revman software (v.5.3) and Stata (version 15.0).

ETHICS AND DISSEMINATION

Ethics approval is not required because the individual patient data will not be involved, with no privacy concerns. This systematic review and meta-analysis will provide a reference for CFS patients and clinicians on the non-drug interventions. We will publish and disseminate the results of this review in a peer-reviewed journal or relevant conference.

OSF REGISTRATION NUMBER

10.17605/OSF.IO/7SHD9 (https://osf.io/7shd9).

Electroacupuncture alleviates diabetic neuropathic pain in rats by suppressing P2X3 receptor expression in dorsal root ganglia

Diabetic neuropathic pain (DNP) is a troublesome diabetes complication all over the world. P2X3 receptor (P2X3R), a purinergic receptor from dorsal root ganglion (DRG), has important roles in neuropathic pain pathology and nociceptive sensations. Here, we investigated the involvement of DRG P2X3R and the effect of 2 Hz electroacupuncture (EA) on DNP. We monitored the rats' body weight, fasting blood glucose level, paw withdrawal thresholds, and paw withdrawal latency, and evaluated P2X3R expression in DRG. We found that P2X3R expression is upregulated on DNP, while 2 Hz EA is analgesic against DNP and suppresses P2X3R expression in DRG. To evaluate P2X3R involvement in pain modulation, we then treated the animals with A317491, a P2X3R specific antagonist, or α β-me ATP, a P2X3R agonist. We found that A317491 alleviates hyperalgesia, while α β-me ATP blocks EA's analgesic effects. Our findings indicated that 2 Hz EA alleviates DNP, possibly by suppressing P2X3R upregulation in DRG.

Acupoint Catgut Embedding for Insomnia: A Meta-Analysis of Randomized Controlled Trials

OBJECTIVES

A Meta-analysis was carried out to evaluate the efficacy and safety of acupoint catgut embedding (ACE), a procedure of embedding sutures made of absorbable materials into the skin tissue of acupoints, on insomnia.

METHODS

Relevant clinical randomized controlled trials (RCTs) were comprehensively searched from eleven electronic databases (up to 1 March 2020). Two authors independently screened literature, extracted data, and assessed the risk of bias of included studies. Stata 12 and RevMan 5.3.0 software were used for meta-analysis. PyCharm 2019 and Gephi software (version 0.9.2) were used for complex network analysis.

RESULTS

Thirty-four RCTs involving 2,655 patients were included. The meta-analysis suggested that ACE induced a better clinical efficacy compared with that in the estazolam tablets (EZ) group (RR = 1.22, 95% CI: 1.13, 1.31) or in the acupuncture (ACU) group (RR = 1.21, 95% CI: 1.14, 1.28) and could significantly reduce the score of Pittsburgh Sleep Quality Index (P < 0.05). ACE resulted in better long-term efficacy compared to that in the EZ group (RR = 1.87, 95% CI: 1.58, 2.22) and ACU group (RR = 1.30, 95% CI: 1.14, 1.48). ACE could significantly reduce the incidence of adverse events (RR = 0.30, 95% CI: 0.15, 0.60) compared with that in the EZ group. Complex network analysis indicated that acupoints of BL23, SP6, PC6, BL15, BL20, BL18, and HT7 were the core acupoints selected in ACE for insomnia.

CONCLUSION

The clinical efficacy of ACE for insomnia is better than that of other interventions (EZ and ACU) in both short-term and long-term observations. Considering the efficacy and reduced visits to the clinic by ACE, the present study provides a practical and convenient complementary and alternative therapy for insomnia. This trial is registered with PROSPERO CRD 42020169866.

Applying Complex Network and Cell-Cell Communication Network Diagram Methods to Explore the Key Cytokines and Immune Cells in Local Acupoint Involved in Acupuncture Treating Inflammatory Pain

Manual acupuncture (MA) can effectively treat a variety of diseases, but its specific mechanism remains unclear. The “acupoint network” activated by MA participates in MA signal transduction, in which immune-related cells and cytokines play an important role. However, which cells and cytokines in the acupoint have changed after MA? What is the network relationship between them? Which cells and cytokines may play the most important role in MA effect? These problems are unclear. In this study, on the basis of affirming the analgesic, detumescence, and anti-inflammatory effect of MA, the concentration of 24 cytokines in ST36 acupoint in rats with inflammatory pain after MA treatment was detected by multiplex immunoassay technology. Then, using statistical and complex network and cell-cell communication (CCC) network diagram method to analyze the detected data depicts the network relationship between the cytokines and related cells objectively and establishes cytokine connection network and CCC network, respectively. The results showed that MA reinforced communication intensity between cells while reducing the overall correlation intensity. On this basis, the key cytokines and key cells at three MA time-points were screened out, cytokines IL-6, MCP-1, fibroblasts cell, and monocyte macrophage screened by the three methods at three MA time-points might be the key cytokines or key cells. After that, we detected the macrophages in ST36 acupoint by flow cytometry and immunofluorescence and found that the relative amount of macrophages increased significantly after MA, especially the macrophage of the dermis of skin. This study provided a basis for revealing the initiated mechanism of MA effect.

p38 mitogen-activated protein kinase and pain

Inflammatory and neuropathic pain is initiated by tissue inflammation and nerve injury, respectively. Both are characterized by increased activity in the peripheral and central nervous system, where multiple inflammatory cytokines and other active molecules activate different signaling pathways that involve in the development and/or maintenance of pain. P38 mitogen-activated protein kinase (MAPK) is one member of the MAPK family, which is activated in neurons and glia and contributes importantly to inflammatory and neuropathic pain. The aim of this review is to summarize the latest advances made about the implication of p38 MAPK signaling cascade in pain. It can deepen our understanding of the molecular mechanisms of pain and may help to offer new targets for pain treatment.

Acupuncture for Pain Management: Molecular Mechanisms of Action

Acupuncture reduces pain by activating specific areas called acupoints on the patient’s body. When these acupoints are fully activated, sensations of soreness, numbness, fullness, or heaviness called De qi or Te qi are felt by clinicians and patients. There are two kinds of acupuncture, manual acupuncture and electroacupuncture (EA). Compared with non-acupoints, acupoints are easily activated on the basis of their special composition of blood vessels, mast cells, and nerve fibers that mediate the acupuncture signals. In the spinal cord, EA can inhibit glial cell activation by down-regulating the chemokine CX3CL1 and increasing the anti-inflammatory cytokine interleukin-10. This inhibits P38 mitogen-activated protein kinase and extracellular signal-regulated kinase pathways, which are associated with microglial activation of the C-Jun N-terminal kinase signaling pathway and subsequent astrocyte activation. The inactivation of spinal microglia and astrocytes mediates the immediate and long-term analgesic effects of EA, respectively. A variety of pain-related substances released by glial cells such as the proinflammatory cytokines tumor necrosis factor [Formula: see text], interleukin-1[Formula: see text], interleukin-6, and prostaglandins such as prostaglandins E2 can also be reduced. The descending pain modulation system in the brain, including the anterior cingulated cortex, the periaqueductal gray, and the rostral ventromedial medulla, plays an important role in EA analgesia. Multiple transmitters and modulators, including endogenous opioids, cholecystokinin octapeptide, 5-hydroxytryptamine, glutamate, noradrenalin, dopamine, [Formula: see text]-aminobutyric acid, acetylcholine, and orexin A, are involved in acupuncture analgesia. Finally, the “Acupuncture [Formula: see text]” strategy is introduced to help clinicians achieve better analgesic effects, and a newly reported acupuncture method called acupoint catgut embedding, which injects sutures made of absorbable materials at acupoints to achieve long-term effects, is discussed.

Acupoint Catgut Embedding Improves the Lipopolysaccharide-Induced Acute Respiratory Distress Syndrome in Rats

Background

This study investigated the potential therapeutic effects of acupoint catgut embedding (ACE) at ST36 and BL13 on lipopolysaccharide- (LPS-) induced acute respiratory distress syndrome (ARDS) in rats.

Materials and Methods

Male Sprague-Dawley rats were randomized into the normal saline (NS group with a sham procedure), lipopolysaccharide (LPS group with a sham procedure), and LPS plus ACE (LPS+ACE with ACE at bilateral BL13 and ST36 acupoints one day before LPS injection) groups. After intratracheal instillation of normal saline or LPS (0.5 mg/kg), all rats were subjected to mechanical ventilation for 4 h. Their blood gas was analyzed before and after lung injury, and their lung pressure-volumes were measured longitudinally. The levels of TNF-α, IL-6, IL-10, and phosphatidylcholine (PC) and total proteins (TP) in bronchial alveolar lavage fluid (BALF) were assessed. Their wet to dry lung weight ratios, histology, myeloperoxidase (MPO), superoxide dismutase (SOD) activity, and malondialdehyde (MDA) levels were measured. Their lung aquaporin 1 (AQP1) and Occludin protein levels were analyzed.

Results

LPS administration significantly decreased the ratios of PaO₂/FiO₂ and pressure-volumes and induced lung inflammation and injury by increased concentrations of TNF-α, IL-6, IL-10, and TP in BALF and MPO and MDA in the lung but decreased PC in BALF and SOD activity in the lungs. LPS also reduced AQP1 and Occludin protein levels in the lung of rats. In contrast, ACE significantly mitigated the LPS-induced lung injury, inflammation, and oxidative stress and preserved the AQP1 and Occludin contents in the lung of rats.

Conclusions

ACE significantly improved respiratory function by mitigating inflammation and oxidative stress and preserving AQP1 and Occludin expression in the lung in a rat model of LPS-induced ARDS.

The multifunctional peptide DN-9 produced peripherally acting antinociception in inflammatory and neuropathic pain via μ- and κ-opioid receptors

BACKGROUND AND PURPOSE

Considerable effort has recently been directed at developing multifunctional opioid drugs to minimize the unwanted side effects of opioid analgesics. We have developed a novel multifunctional opioid agonist, DN-9. Here, we studied the analgesic profiles and related side effects of peripheral DN-9 in various pain models.

EXPERIMENTAL APPROACH

Antinociceptive effects of DN-9 were assessed in nociceptive, inflammatory, and neuropathic pain. Whole-cell patch-clamp and calcium imaging assays were used to evaluate the inhibitory effects of DN-9 to calcium current and high-K⁺ -induced intracellular calcium ([Ca²⁺ ]_i ) on dorsal root ganglion (DRG) neurons respectively. Side effects of DN-9 were evaluated in antinociceptive tolerance, abuse, gastrointestinal transit, and rotarod tests.

KEY RESULTS

DN-9, given subcutaneously, dose-dependently produced antinociception via peripheral opioid receptors in different pain models without sex difference. In addition, DN-9 exhibited more potent ability than morphine to inhibit calcium current and high-K⁺ -induced [Ca²⁺ ]_i in DRG neurons. Repeated treatment with DN-9 produced equivalent antinociception for 8 days in multiple pain models, and DN-9 also maintained potent analgesia in morphine-tolerant mice. Furthermore, chronic DN-9 administration had no apparent effect on the microglial activation of spinal cord. After subcutaneous injection, DN-9 exhibited less abuse potential than morphine, as was gastroparesis and effects on motor coordination.

CONCLUSIONS AND IMPLICATIONS

DN-9 produces potent analgesia with minimal side effects, which strengthen the candidacy of peripherally acting opioids with multifunctional agonistic properties to enter human studies to alleviate the current highly problematic misuse of classic opioids on a large scale.

Electroacupuncture Attenuates Limb Ischemia-Reperfusion-Induced Lung Injury Via p38 Mitogen-Activated Protein Kinase-Nuclear Factor Erythroid-2-Related Factor-2/Heme Oxygenase Pathway

BACKGROUND

Electroacupuncture has been reported to protect the body from organ damages, but its mechanisms remain to be explored. This research was designed to investigate the function of electroacupuncture in lung injury resulted from hind limb ischemia-reperfusion (LIR) and whether p38 mitogen-activated protein kinase (p38 MAPK)-mediated nuclear factor erythroid-2-related factor-2 (Nrf2)/heme oxygenase (HO)-1 pathway contributes to the protective effect of electroacupuncture on LIR-originated lung damage.

MATERIALS AND METHODS

Rabbits were subjected to occluding femoral artery for 2 h. Then they received reperfusion for 4 h to establish lung injury model. Electroacupuncture stimulation was performed bilaterally at Feishu and Zusanli acupoints for 15 min once a day for 5 d before the experiment and throughout the hind LIR model performing in the experimental day. Blood samples and lung tissues were collected to examine the role of electroacupuncture treatment in inflammatory response, oxidative stress, and lung injury. Both the protein expression and the messenger RNA level of Nrf2 and HO-1 were detected.

RESULTS

The results showed that electroacupuncture treatment remarkably alleviated lung injury, decreased inflammatory cytokines secretion, attenuated lung oxidative stress, increased the amount of Nrf2 and HO-1, and increased the ratio of phospho-p38 MAPK to p38 MAPK after LIR. However, the protective effects exerted by electroacupuncture were reversed to some extent by the preconditioning with SB203580, a p38 MAPK-specific inhibitor.

CONCLUSIONS

These results suggested that electroacupuncture could attenuate lung injury in rabbits subjected to LIR by inhibition of proinflammatory cytokine response and oxidative stress through activating p38 MAPK-mediated Nrf2/HO-1 pathway.

Inhibition of chemokine CX3CL1 in spinal cord mediates the electroacupuncture-induced suppression of inflammatory pain

Purpose

Chemokine CX3CL1 and its receptor CX3CR1 in the lumbar spinal cord play crucial roles in pain processing. Electroacupuncture (EA) is recognized as an alternative therapy in pain treatment due to its efficacy and safety. However, the analgesic mechanism of EA remains unclear. The aim of this study was to investigate whether EA suppressed complete Freund’s adjuvant (CFA)-induced pain via modulating CX3CL1-CX3CR1 pathway.

Materials and methods

Inflammatory pain was induced by intraplantar injection of CFA to the left hind paw of Sprague-Dawley rats. EA with 2 Hz for 30 mins was given to bilateral Zusanli acupoints (ST36) on the first and third day after CFA injection. Mechanical allodynia and thermal hyperalgesia were tested with von Frey tests and Hargreaves tests, respectively. The expressions of CX3CL1, CX3CR1 and p38 mitogen-activated protein kinase (MAPK) were quantified with Western blots. The release of IL-1β, IL-6 and TNF-α were evaluated with ELISA. Recombinant CX3CL1 or control IgG were then injected through intrathecal catheters in the EA-treated CFA model rats. The behavioral tests, p38 MAPK activation and cytokine release were then evaluated.

Results

EA significantly inhibited inflammatory pain induced by CFA for 3 days. Meanwhile, EA downregulated the expression of CX3CL1 but not CX3CR1 in the lumbar spinal cord of the CFA rats. Besides, activation of p38 MAPK and the release of pain-related cytokines (IL-1β, IL-6 and TNF-α) were inhibited by EA. Intrathecal injection of CX3CL1 largely reversed the analgesic effect of EA treatment and re-activated p38 MAPK signaling, and resulted in pro-inflammatory cytokines increase in acupuncture-treated rats.

Conclusion

Our findings indicate that EA alleviates inflammatory pain via modulating CX3CL1 signaling in lumbar spinal cord, revealing a potential mechanism of anti-nociception of EA in inflammatory pain.

The Mechanism of MAPK Signal Transduction Pathway Involved with Electroacupuncture Treatment for Different Diseases

The mitogen-activated protein kinase (MAPK) signal transduction pathway plays an important role in the regulation of various diseases, such as cardiovascular and cerebrovascular diseases, and takes part in anti-inflammatory effects, analgesic effects, protection against injury, and maintenance of gastrointestinal functions. Electroacupuncture therapy is an external therapy used in traditional Chinese medicine. By adding external electrical stimulation to traditional acupuncture, the stimulus gets doubled and the therapeutic efficacy gets enhanced accordingly. It combines the benefits of both acupuncture and electrical stimulation. In recent years, some studies have explored the molecular mechanisms of MAPK signal pathways involved with electroacupuncture treatment. Based on these recent studies, this article summarizes the mechanisms of MAPK signal transduction pathways involved with electroacupuncture treatment. This adds great value to the studies of molecular mechanisms of electroacupuncture treatment and also provides an effective reference for its clinical use.

Cocaine-induced release of CXCL10 from pericytes regulates monocyte transmigration into the CNS

Cocaine is known to facilitate the transmigration of inflammatory leukocytes into the brain, an important mechanism underlying neuroinflammation. Pericytes are well-recognized as important constituents of the blood-brain barrier (BBB), playing a key role in maintaining barrier integrity. In the present study, we demonstrate for the first time that exposure of human brain vascular pericytes to cocaine results in enhanced secretion of CXCL10, leading, in turn, to increased monocyte transmigration across the BBB both in vitro and in vivo. This process involved translocation of σ-1 receptor (σ-1R) and interaction of σ-1R with c-Src kinase, leading to activation of the Src-PDGFR-β-NF-κB pathway. These findings imply a novel role for pericytes as a source of CXCL10 in the pericyte-monocyte cross talk in cocaine-mediated neuroinflammation, underpinning their role as active components of the innate immune responses.

Acupoint Embedding of Polyglactin 910 Sutures in Patients with Chronic Pain due to Cervical Spondylotic Radiculopathy: A Multicenter, Randomized, Controlled Clinical Trial

Objective

We aimed to investigate the effectiveness of acupoint polyglactin 910 (PGLA) embedding in patients with cervical spondylotic radiculopathy (CSR).

Methods

A total of 102 CSR patients with neck and shoulder pain were recruited and assigned randomly into three groups: the sham acupoint embedding (SAE) group, the middle-layer acupoint PGLA embedding (MAPE) group, and the deep-layer acupoint PGLA embedding (DAPE) group. The primary outcomes were Visual Analog Scale (VAS) scores showing the analgesic effects of treatment. Secondary outcomes included clinical symptoms (evaluated by the Yasuhisa Tanaka 20 (YT-20) score and the neck disability index (NDI)) and patient health status (evaluated by the 36-item short-form survey (SF-36)) as reported in the trial.

Results

Compared with the SAE group, VAS scores were significantly reduced at 1, 2, 3, 4, and 10 weeks after the first treatment in both the DAPE and MAPE groups (P < 0.001). Moreover, there were statistically significant increases in the weekly YT-20 scores and significant reductions of the weekly NDI scores compared with baseline values in both the DAPE and MAPE groups (P < 0.001). Compared with baseline values, both the physical component summary (PCS) and the mental component summary scores of the SF-36 at 2, 3, 4, and 10 weeks were significantly higher in the DAPE and MAPE groups (P < 0.001). There were significant lower VAS scores (P < 0.01), higher PCS scores (P < 0.05) at 3 weeks, and lower NDI scores (P < 0.05) at 4 weeks in the DAPE group compared with the MAPE group.

Conclusions

Both DAPE and MAPE showed significant and long-lasting effects on alleviating pain and improving clinical symptoms as well as quality of life in CSR patients with neck and shoulder pain. A more intense effect was seen in the DAPE group compared with the MAPE group.