Hz Electroacupuncture Research Articles

Electroacupuncture Improves Cognitive Function in Senescence-Accelerated P8 (SAMP8) Mice via the NLRP3/Caspase-1 Pathway.

Background. Clinically, electroacupuncture (EA) is the most common therapy for aging-related cognitive impairment (CI). However, the underlying pathomechanism remains unidentified. The aims of this study were to observe the effect of EA on cognitive function and explore the potential mechanism by which EA acts on the NLRP3/caspase-1 signaling pathway. Main Methods. Thirty male SAMP8 mice were randomly divided into the model, the 2 Hz EA and 10 Hz EA groups. Ten male SAMR1 mice were assigned to the control group. Cognitive function was assessed through the Morris water maze test. Hippocampal morphology and cell death were observed by HE and TUNEL staining, respectively. The serum IL-1β, IL-6, IL-18, and TNF-α levels were measured by ELISA. Hippocampal NLRP3, ASC, caspase-1, GSDM-D, IL-1β, IL-18, Aβ, and tau proteins were detected by Western blotting. Key Findings. Cognitive function, hippocampal morphology, and TUNEL-positive cell counts were improved by both EA frequencies. The serum IL-1β, IL-6, IL-18, and TNF-α levels were decreased by EA treatment. However, 10 Hz EA reduced the number of TUNEL-positive cells in the CA1 region and serum IL-1β and IL-6 levels more effectively than 2 Hz EA. NLRP3/caspase-1 pathway-related proteins were significantly downregulated by EA, but 2 Hz EA did not effectively reduce ASC protein expression. Interestingly, both EA frequencies failed to reduce the expression of Aβ and tau proteins. Significance. The effects of 10 Hz EA at the GV20 and ST36 acupoints on the NLRP3/caspase-1 signaling pathway may be a mechanism by which this treatment relieves aging-related CI in mice.

Case reports: Electroacupuncture decreases the climacteric symptoms by calcitonin gene-related peptide modulation

ObjectiveThe purpose of the current study was to evaluate the modulation of Calcitonin gene-related peptide (CGRP) associated to the efficacy of Electroacupuncture (EA) in the reduction of climacteric symptoms. MethodsNine women between 51 and 59 years old with climacteric syndrome in menopause or perimenopause were included. Patients with hormone replacement therapy, psychiatric treatment with antidepressants, or acupuncture treatment in the last 3 months were excluded. A 4 Hz EA treatment was performed at acupoints Shenshu (BL-23), Pishu (BL-20), Guanyuan (REN-4), Taixi (KID-3), Fuliu (KID-7), Sanyinjiao (SP-6) and Neiguan (P-6) points. Women were treated two times a week for five consecutive weeks for a total treatment of 10 sessions. The menopause rating scale (MRS) was used to evaluate symptoms reduction and CGRP gene expression was measured before and after 10 EA session. ResultsThe results shown that climacteric symptoms diminish significantly after EA therapy. CGRP gene expression was down-regulated, evidencing a decrease of 5-fold after EA therapy respect to the initial condition. ConclusionEA treatment was associated with improvement in patients with climacteric syndrome and may be related to modulation of CGRP levels.

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.

Comparing the analgesic efficacy between 100 Hz and 2 Hz electroacupuncture on patients with lumbar osteoarthritis

Chronic low back pain (CLBP) represents one of the major causes of increasing disability worldwide. Electroacupuncture with different frequencies at the Hua Tuo Jia Ji acupoints has been used to treat CLBP in patients with lumbar osteoarthritis. Basic studies demonstrate that 100 Hz or 2 Hz electroacupuncture has pain-relief effects on CLBP; however, clinical evidence for choosing which frequency is still limited. Thus, our study aims to compare the effects of 100 Hz to 2 Hz electroacupuncture for CLBP on patients with lumbar osteoarthritis. A randomized controlled trial of 124 patients with lumbar osteoarthritis at the Traditional Medicine Hospital at Ho Chi Minh City from September 2018 to July 2019. Patients were randomly allocated to either intervention group (n = 62) with a 100 Hz electroacupuncture or control group (n = 62) with 2 Hz electroacupuncture at the L2-S1 Hua Tuo Jia Ji acupoints for 14 days. Du Huo Ji Sheng Tang’s decoction was also administered in both groups. Primary trial outcomes were evaluated by the QDSA score and the proportion of patients who achieved pain relief thresholds. After 14 days of treatment, the QDSA score in the intervention group decreased significantly compared to the control group. Eighty-seven percent of patients in the intervention group had pain relief of ≥70%, and only 45% of patients in the control group had such a result. The lumbar flexion range of motion in the 100 Hz group tended to be better than in the 2 Hz group. 100 Hz electroacupuncture had superior analgesic effects on lumbar osteoarthritis to 2 Hz electroacupuncture.

Electroacupuncture Attenuates Surgical Stress-Induced Reduction of T Lymphocytes through Modulation of Peripheral Opioid System.

To investigate the action mechanisms of electroacupuncture (EA) on postoperative immunosuppression. Male C57BL/6 mice (5`-7 weeks old) were randomly divided into: the sham injury group, the surgical trauma stressed group, the EA group [surgery + 2/100 Hz EA at Neiguan (PC 6)], and the EA+ Nal (surgery + EA + intraperitoneal injection of naloxone). Abdominal surgical trauma stress mice model was established. EA was performed on bilateral PC 6 acupoints by an EA apparatus (2/100 Hz) for 20 min once a day for 3 days. The mRNA expressions of MOR, DOR, and KOR in thymus and L3`-L5 dorsal root ganglions (DRG) were determined by quantitative real-time polymerase chain reaction (qRT-PCR) and the protein expressions of MOR, DOR, and KOR in thymus were measured by Western blot. Flow cytometry assay was used to detect the levels of T lymphocyte subtypes in the peripheral blood. Surgical trauma induced decreased the mRNA expression level of MOR in both thymus (P<0.01) and L3`-L5 DRGs (P<0.05). Moreover, EA treatment not only significantly attenuated the MOR protein and mRNA expression in the thymus (both P<0.05), but also markedly increased expression of DOR and KOR opioid receptor in thymus (P<0.01). However, the mRNA expressions of opioid receptors were not regulated by EA in the DRG (all P>0.05). Furthermore, T lymphocyte population of CD3+ and CD4+ was decreased in the peripheral blood after surgical trauma (both P<0.01). EA treatment can significantly elevate the population of CD3+ (P<0.01), CD4+ (P<0.05) and CD8+ T cells (P<0.01). Intraperitoneal injection of the non-selective opioid receptor antagonist naloxone blocked the up-regulation of T lymphocytes by EA. EA may improve postoperative immunosuppression through the peripheral opioid system.

Electroacupuncture Modulates Spinal BDNF/TrκB Signaling Pathway and Ameliorates the Sensitization of Dorsal Horn WDR Neurons in Spared Nerve Injury Rats.

Neuropathic pain is more complex and severely affects the quality of patients’ life. However, the therapeutic strategy for neuropathic pain in the clinic is still limited. Previously we have reported that electroacupuncture (EA) has an attenuating effect on neuropathic pain induced by spared nerve injury (SNI), but its potential mechanisms remain to be further elucidated. In this study, we designed to determine whether BDNF/TrκB signaling cascade in the spinal cord is involved in the inhibitory effect of 2 Hz EA on neuropathic pain in SNI rats. The paw withdrawal threshold (PWT) of rats was used to detect SNI-induced mechanical hypersensitivity. The expression of BDNF/TrκB cascade in the spinal cord was evaluated by qRT-PCR and Western blot assay. The C-fiber-evoked discharges of wide dynamic range (WDR) neurons in spinal dorsal horn were applied to indicate the noxious response of WDR neurons. The results showed that 2 Hz EA significantly down-regulated the levels of BDNF and TrκB mRNA and protein expression in the spinal cord of SNI rats, along with ameliorating mechanical hypersensitivity. In addition, intrathecal injection of 100 ng BDNF, not only inhibited the analgesic effect of 2 Hz EA on pain hypersensitivity, but also reversed the decrease of BDNF and TrκB expression induced by 2 Hz EA. Moreover, 2 Hz EA obviously reduced the increase of C-fiber-evoked discharges of dorsal horn WDR neurons by SNI, but exogenous BDNF (100 ng) effectively reversed the inhibitory effect of 2 Hz EA on SNI rats, resulting in a remarkable improvement of excitability of dorsal horn WDR neurons in SNI rats. Taken together, these data suggested that 2 Hz EA alleviates mechanical hypersensitivity by blocking the spinal BDNF/TrκB signaling pathway-mediated central sensitization in SNI rats. Therefore, targeting BDNF/TrκB cascade in the spinal cord may be a potential mechanism of EA against neuropathic pain.

Electroacupuncture ameliorates mechanical hypersensitivity by down-regulating spinal Janus kinase 2/signal transducer and activation of transcription 3 and interleukin 6 in rats with spared nerve injury.

Evidence shows that the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway participates in the pathogenesis of neuropathic pain. Our previous study revealed that electroacupuncture (EA) attenuated neuropathic pain via activation of alpha-7 nicotinic acetylcholine receptor (α7nAChR) in the spinal cord. However, whether 2 Hz EA alleviates neuropathic pain by regulating the downstream molecules JAK2/STAT3 has not been fully clarified. Paw withdrawal threshold (PWT) was used as a marker of mechanical allodynia in rats with spared nerve injury (SNI). After applying 2 Hz EA on day 3, 7, 14 and 21 post-surgery, spinal expression of JAK2, STAT3 and pro-inflammatory cytokine interleukin (IL)-6 was examined using quantitative reverse transcription and real-time polymerase chain reaction (qRT-PCR) and Western blot analysis. Intrathecal injection of the α7nAChR antagonist alpha-bungarotoxin (α-Bgtx) was used to further explore the mechanism underlying the effects of 2 Hz EA on expression of JAK2/STAT3 in SNI rats. It was found that levels of spinal STAT3 and IL-6 mRNA, as well as levels of phosphorylated (p)-JAK2, p-STAT3 and IL-6 protein, were markedly increased in SNI rats. 2 Hz EA attenuated the SNI-induced up-regulation of p-JAK2, p-STAT3 and IL-6 expression in the spinal cord. Furthermore, intrathecal injection of α-Bgtx (1.0 μg/kg) not only inhibited the effect of 2 Hz EA on mechanical hypersensitivity but also ameliorated the down-regulation of p-JAK2, p-STAT3 and IL-6 expression induced by 2 Hz EA. This study revealed that 2 Hz EA attenuated SNI-induced mechanical hypersensitivity and the concomitant up-regulation of spinal JAK2, STAT3 and IL-6 in SNI rats, suggesting that suppression of the JAK2/STAT3 signaling pathway might be the mechanism underlying the therapeutic effect of 2 Hz EA on neuropathic pain.

Neuromodulating Influence of Two Electroacupuncture Treatments on Heart Rate Variability, Stress, and Vagal Activity.

Introduction: Although the clinical use of electro-acupuncture is widespread, the neuromodulating influence of various applied frequencies is not well established. Objectives: Heart rate variability (HRV), stress and parasympathetic recovery are closely related to health, longevity and vitality in humans. This study was undertaken to determine the influence of different electro-therapy frequencies on various autonomic nervous system markers when applied to a Battlefield Acupuncture Protocol (BFA). Design: A detailed comparison of autonomic nervous system (ANS) response to low frequency (LF) 2.5 Hz electro-acupuncture and mid-frequency (MF) 15 Hz electro-acupuncture applied by point stimulation to acupuncture points was undertaken on 2 groups of 12 patients. Interventions: Both LFEA and MFEA were applied to Battlefield Acupuncture protocol, consisting of five (5) key acupuncture ear (auricular) points that isolate the autonomic nervous system (ANS) and central nervous system's role in the chronic/acute pain cycle. Evaluations entailed an advanced status of autonomic nervous system (ANS) function through Electro-Cardiogram (ECG) baseline markers reflecting: sympathetic stress (SI); parasympathetic vagal tone (high frequency [HF]) and heart rate variability (HRV = total power). All were repeated subsequent to electro-therapy using 2 separate electro-modalities of low-frequency (2.5 Hz) electro-acupuncture (LFEA) and Mid-Frequency (15 Hz) electro-acupuncture (MFEA). All 24 patients received one (1) elector-acupuncture session. Results: The autonomic nervous system response to LFEA (2.5 Hz) reflected a statistically significant pre-post improvement in three of the markers collected: heart rate variability (HRV) improved by 61% [p = 0.002]; sympathetic stress (SI) reduced 42% [p = 0.002]; and parasympathetic vagal tone (HF) increased 56% [p = 0.017]. In contrast, MFEA (15 Hz) showed positive but non-significant changes in outcomes in all nervous system markers. Conclusions: The autonomic nervous system response with LFEA showed a measurable reduction in sympathetic stress with subsequent improvement in vagal tone, and HRV. This positive sympathetic nervous system deactivation from LFEA application shown in this study could have a major impact on other pathologies related to human health and longevity. Further cohort studies are warranted to determine the validity of these outcomes.

Electroacupuncture Alleviates Mechanical Allodynia in a Rat Model of Complex Regional Pain Syndrome Type-I via Suppressing Spinal CXCL12/CXCR4 Signaling

Complex regional pain syndrome (CRPS) results in chronic and excruciating pain in patients. Conventional therapies lack effectiveness, rendering it one of the most difficult to treat neurological conditions.. Electroacupuncture (EA) is an effective alternative therapy for pain relief. Here, we investigated whether EA exerts analgesic effect on a rat model of CRPS type-I (CRPS-I) and related mechanisms. The rat chronic postischemic pain (CPIP) model was established to mimic CRPS-I. 100Hz EA exerted robust and persistent antiallodynic effect on CPIP model compared with 2 Hz EA or sham EA. EA markedly suppressed the overexpression of CXCL12/CXCR4 in spinal cord dorsal horn (SCDH) of CPIP model, leading to substantial decrease in neuronal and glial cell activities in SCDH. Pharmacological blocking CXCR4 mimicked EA-induced antiallodynic effect and related cellular events in SCDH, whereas exogenous CXCL12 abolished EA's effect. CXCR4 signaling resulted in ERK activation in SCDH, contributing to mechanical allodynia of CPIP model rats, whereas EA markedly reduced ERK activation. Therefore, we demonstrated that EA interferes with CXCL12/CXCR4 signaling in SCDH and downstream ERK pathway to exert robust antiallodynic effect on an animal model of CRPS-I. Our work suggests that EA may be a potential therapeutic option for CRPS-I in clinic. PerspectiveOur work identified that EA exerts robust antiallodynic effect on an animal model of CRPS-I, via mechanisms involving inhibition of CXCL12/CXCR4 signaling. EA further attenuates downstream neuronal and glial cell activation and ERK pathway in SCDH. This work suggests that EA may be a potential therapeutic option for CRPS-I management in clinic.

Effect of Different Frequencies of Electroacupuncture on Post-Stroke Dysphagia in Mice.

The aim of this study was to determine the optimum frequency of electroacupuncture (EA) for the treatment of dysphagia after stroke. Male C57BL/6J mice were randomly divided into five groups: normal, model, 2Hz, 50Hz, and 100Hz groups. All mice received a photochemical ischemia, except the normal group. The EA parameters were 1mA for 15min, with different frequencies (2, 50, and 100Hz) applied. After a three day treatment, neuronal activation was detected by the expression of c-Fos. A multi-channel electrophysiological technique was used to assess the discharge of contralateral neurons and the neuron types in each group. The concentration of brain-derived neurotrophic factor (BDNF) in the contralateral neurons was also examined. In addition, the dysfunction of swallowing in mice was calculated according to the lick counts and the lick-lick interval within a certain period of time. The number of c-Fos neurons (P < 0.05) and the expression of BDNF (P < 0.05) increased after the 2Hz EA treatment. The total frequency of neuron discharge in the 2Hz group increased compared with the model group (P < 0.05). The pattern of sorted neuron populations was similar between the normal and 2Hz groups. Consistent with these results, the lick counts increased (P < 0.05) and the lick-lick interval decreased after the 2Hz EA treatment, which indicated a functional improvement in swallowing. These results indicated that the 2Hz EA treatment had a good effect on dysphagia after stroke.

Electroacupuncture of the Ophthalmic Branch of the Trigeminal Nerve: Effects on Prefrontal Cortex Blood Flow.

Objective: The current authors observed enhanced cerebral blood flow (CBF) in the prefrontal cortex (PFC) in response to 100-Hz electroacupuncture (EA) stimulation of the ophthalmic branch of the trigeminal nerve. However, it is not yet clear if responsiveness to 100-Hz EA depends on stimulus intensity. This study examined the effects of stimulus strength on PFC CBF during 100-Hz EA of the ophthalmic branch of the trigeminal nerve. Materials and Methods: Twelve subjects underwent 3 acupuncture sessions: I, control, no stimulation; II, 0.1 mA EA; and III, 0.2 mA EA). Needles were inserted 1 cm lateral of the head median line; the anterior insertion point was on the front hairline and the posterior insertion point was ∼7 cm behind the hairline. Stimulation frequency was set to 100-Hz. PFC CBF was measured in terms of oxygenated, deoxygenated, and total hemoglobin (OxyHb, DeoxyHb, TotalHb, respectively), using 16-channel (Ch) near-infrared spectroscopy. Results: Stimulation of 0.2 mA was associated with significant elevation of OxyHb levels in the 0.1 mA condition in Chs 6, 10, and 12. Ch 2-6, 10, 12 signals were notably higher than in the control condition. Stimulation of 0.2 mA and 0.1 mA were associated with significant declines in DeoxyHb levels, compared to the control condition in Ch 4. Finally, 0.2 mA stimulation in Chs 12 and 13 was associated with significant elevation of TotalHb levels in the control condition. Conclusions: Using 0.2-mA stimulation, 100-Hz EA of the ophthalmic nerve enhances PFC CBF more strongly than 0.1-mA stimulation.

Electroacupuncture Treatment Suppresses Transcription Factor IRF8 in Spinal Cord of Rats with Spared Nerve Injury.

Objective Neuropathic pain with complex mechanisms has become a major public health problem that greatly impacts patients' quality of life. Therefore, novel and more effective strategies against neuropathic pain need further investigation. Electroacupuncture (EA) has an ameliorating effect on neuropathic pain following spared nerve injury (SNI), but the underlying mechanism remains to be fully clarified. Interferon regulatory factor 8 (IRF8), a critical transcription factor, was reported to be involved in the modulation of neuropathic pain. Here, we focused on exploring whether 2 Hz EA stimulation exerts an inhibitory action on spinal IRF8 in SNI rats. Methods In this study, SNI rats were treated with 2 Hz EA once every other day for 21 days. Paw withdrawal threshold (PWT) was applied to determine the analgesic effect of 2 Hz EA on SNI rats. The spinal IRF8 and CX3CRl expressions were detected with qRT-PCR and western blot, and immunofluorescence staining was used to evaluate colocation of IRF8 or CX3CRl with microglial activation marker CD11b in the spinal cord. Results It was found that SNI induced significant elevation of spinal IRF8 and CX3CRl mRNA and protein expression. Additionally, immunofluorescence results showed that SNI elicited the coexpression of IRF8 with CD11b, as well as CX3CRl with CD11b in the spinal cord. Meanwhile, 2 Hz EA treatment of SNI rats not only reduced IRF8 and CX3CRl mRNA and protein expression, but also reversed the coexpression of IRF8 or CX3CRl with CD11b in the spinal cord, along with an attenuation of SNI-evoked mechanical hypersensitivity. Conclusion This experiment highlighted that 2 Hz EA can inhibit IRF8 expression and microglial activation in the spinal cord of SNI rats. Hence, targeting IRF8 may be a promising therapeutic strategy for 2 Hz EA treatment of neuropathic pain.

Effects of electroacupuncture on the intestinal motility and local inflammation are modulated by acupoint selection and stimulation frequency in postoperative ileus mice.

Electroacupuncture (EA) is widely used in various gastrointestinal diseases around the world, including POI. Here, we investigated different therapeutic effects of EA using lower limb and abdomen acupoints. Intestinal manipulation was performed in 88 mice, and eight mice underwent a sham operation. Forty mice were randomly divided into model group and four EA groups receiving stimulation at ST36 (2, 10, 30, 100Hz). The most effective frequency was then used in the following experiments. Forty-eight mice were randomly divided into six groups receiving EA treatment at ST37, ST39, ST25, CV4, CV12, and a non-acupuncture point. Gastrointestinal motility and plasma TNF-α, IL-6 were evaluated in all mice. The local immune response and α-smooth muscle actin (α-SMA) expression were assessed by immunofluorescence, ELISA, and HE staining. ST36 stimulated with 10 or 30Hz EA significantly increased the gastrointestinal motility and attenuated peripheral inflammation; however, ST36 stimulated with 2 or 100Hz did not induce any effect. The therapeutic effects on motility and inflammation of 10Hz EA in the ST36 group were similar in the ST36, ST37, ST39, or CV4 groups, but when applied to ST25, CV12 or non-acupoint had no significant differences. EA at ST36, ST37, ST39, or CV4 significantly inhibited local MPO activity, immune cells infiltration, and increased α-SMA. EA at lower limb and abdomen acupoints with the same stimulation parameters had different therapeutic effects on postoperative dysmotility and inflammation. Furthermore, EA protected SMC to improve gastrointestinal transit by reducing local inflammation in the intestinal musculature in POI.

Effects of electroacupuncture of different frequencies on electromyography, NOS and ICC of colon in rats with slow transit constipation

To observe the effects of electroacupuncture (EA) of different frequencies on transmission function, electromyography, nitric oxide synthase (NOS) content and interstitial cells of Cajal (ICC) expression of colon in rat models with slow transit constipation (STC). Of the 50 healthy male Wistar rats, 10 were randomly selected as a normal group and fed with ordinary diet, and the remaining 40 rats were fed with the diet added with the compound diphenoxylate at a dose of 8 mg/(kg·bw) each day for continuous 120 d. The 40 successfully established STC rat models were randomly divided into a model group, a low-frequency EA group (2 Hz), a high-frequency EA group (100 Hz), and a variable-frequency EA group (2 Hz/100 Hz), with 10 rats in each group. Rats in the normal and the model groups were not given any treatment; the low-frequency EA and the high-frequency EA groups were given EA at Tianshu (ST 25), Zusanli (ST 36) and Zhigou (TE 6) with continuous wave at the designated frequency, and the variable-frequency EA group received sparse-dense wave (2 Hz/100 Hz) EA at the same acupoints, once a day for a total of 15 d. After treatment, the colonic transmission function, electromyography, NOS content and ICC expression (calculated by the difference in the area of the C-kit positive cells) of the rats in each group were measured. For the colonic transmission function, compared with the normal group, the first black stool excretion durations of rats in the other groups were significantly prolonged (all P<0.05); compared with the model group, the first black stool excretion durations of rats in the three EA groups were significantly shortened (all P<0.05), which was significantly shorter in the variable-frequency EA group than in the low-frequency EA and high-frequency EA groups (both P<0.05). For the colonic electromyography, compared with the normal group, the amplitude was significantly increased and the frequency was accelerated in rats of the other groups (all P<0.05); compared with the model group, the amplitude was significantly reduced and the frequency was slowed down in the three EA groups (both P<0.05); compared with the low-frequency EA and the high-frequency EA groups, the amplitude was reduced and the frequency was significantly reduced in rats of the variable-frequency EA group (both P<0.05). Compared with the normal group, the colonic NOS contents were significantly increased in the other groups (all P<0.05); compared with the model group, the NOS contents were significantly reduced in the three EA groups (all P<0.05); compared with the low-frequency EA and the high-frequency EA groups, the content was significantly reduced in the variable-frequency EA group (all P<0.05). For the area of rat colonic C-kit-positive cells, compared with the normal group, the areas were significantly reduced in rats of other groups (all P<0.05); compared with the model group, the areas were increased significantly in the three EA groups (all P<0.05); compared with the low-frequency EA group, the area was increased significantly in the variable-frequency EA group (P<0.05). EA, especially EA at the 2 Hz/100 Hz variable-frequency, has a positive treatment effect on the STC model rats. It may improve rats’ colonic function by regulating the electromyography, NOS content and ICC expression of colon.

2 Hz EA Reduces Heroin Withdrawal-Induced Hyperalgesia and Heroin Relapse by Downregulating P2X3 Receptors in DRG Neurons.

Electroacupuncture (EA) has effective analgesic effects. Our previous study demonstrated that the upregulation of P2X3 receptors in the dorsal root ganglia (DRG) might participate in heroin withdrawal-induced hyperalgesia. The aim of this study is to further explore whether 2 Hz EA reduces heroin relapse associated with its analgesic effect and whether P2X3 receptors in the DRG are involved in this process. 2 Hz EA was adopted to treat the heroin SA rats in the present study. Heroin-seeking and pain sensitivity were evaluated. The expression of P2X3 receptors in the DRG was detected. Our results showed that compared with the control group, the reinstatement, thermal hyperalgesia, and mechanical allodynia of the heroin-addicted group were increased significantly. The expression of P2X3 receptors in the DRG was increased markedly. After being treated using 2 Hz EA, reinstatement was reduced, hyperalgesia was decreased, and the upregulated expression of P2X3 receptors in the DRG had decreased significantly compared to that in the heroin-addicted group. Consequently, our results indicated that 2 Hz EA was an effective method for treating heroin-induced hyperalgesia and helping prevent relapse, and the potential mechanism might be related to the downregulation of P2X3 receptor expression in the DRG.

2Hz-electroacupuncture attenuates heroin-seeking behaviors via adjusts CB1-Rs and CB2-Rs expression in relapse-relevant brain regions of heroin self-administration rats.

Opiate addiction has a high rate of relapse. The accumulating evidence shows that electroacupuncture (EA) may be effective for the treatment of opiate relapse. However, the change of expression of CB1-Rs and CB2-Rs involve in 2Hz EA anti-relapse pathway is still unclear. To explore the changes of expression of CB1-Rs and CB2-Rs, heroin self-administration (SA) model rats were adopted and treated using 2Hz EA. The expressions of CB1-Rs and CB2-Rs were observed using immunohistochemistry method. The results showed that, compared with the control group, active pokes in the heroin-addicted group increased, while the active pokes decreased significantly in 2Hz EA group compared with heroin-addicted group. Correspondingly, the expression of CB1-Rs in prefrontal cortex (PFC), hippocampus (Hip), nucleus accumbens (NAc) and ventral tegmental area (VTA) all increased significantly while the expression of CB2-Rs in those relapse-relevant brain regions decreased obviously in heroin-addicted group when compared with the control group. In addition, the expression of CB1-Rs obviously decreased in the 2Hz EA group while the expression of CB2-Rs in those relapse-relevant brain regions increased significantly when compared with the heroin-addicted group. It indicated that 2Hz EA could attenuate the heroin-evoked seeking behaviors effectively. The anti-relapse effects of 2Hz EA might be related to the decrease of CB1-Rs and increase of CB2-Rs expression in relapse-relevant brain regions of heroin SA rats.

Electroacupuncture Relieves CCI-Induced Neuropathic Pain Involving Excitatory and Inhibitory Neurotransmitters.

Neuropathic pain caused by peripheral tissue injuries to the higher brain regions still has no satisfactory therapy. Disruption of the balance of excitatory and inhibitory neurotransmitters is one of the underlying mechanisms that results in chronic neuropathic pain. Targeting neurotransmitters and related receptors may constitute a novel approach for treating neuropathic pain. We investigated the effects of electroacupuncture (EA) on chronic constriction injury- (CCI-) induced neuropathic pain. The mechanical allodynia and thermal hyperalgesia pain behaviors were relieved by 15 Hz EA but not by 2 and 50 Hz. These phenomena were associated with increasing γ-amino-butyric acid (GABA) receptors in the hippocampus and periaqueductal gray (PAG) but not N-methyl-D-aspartate receptors. Furthermore, excitatory neurotransmitter glutamate was decreased in the hippocampus and inhibitory neurotransmitter GABA was increased in the PAG under treatment with EA. These data provide novel evidence that EA modulates neurotransmitters and related receptors to reduce neuropathic pain in the higher brain regions. This suggests that EA may be a useful therapy option for treating neuropathic pain.

Electroacupuncture Alleviates Spared Nerve Injury-Induced Neuropathic Pain And Modulates HMGB1/NF-κB Signaling Pathway In The Spinal Cord.

BackgroundNeuropathic pain with complications greatly affects patients worldwide. High mobility group box 1 (HMGB1) has been shown to contribute to the pathogenesis of neuropathic pain; thus, suppression of HMGB1 may provide a novel therapeutic option for neuropathic pain. Electroacupuncture (EA) has been indicated to be effective in attenuating neuropathic pain, but the underlying mechanism remains to be fully clarified. We aim to explore whether 2Hz EA stimulation regulates the spinal HMGB1/NF-κB signaling in neuropathic pain induced by spared nerve injury (SNI).Materials and methodsPaw withdrawal threshold and CatWalk gait analysis were used to assess the effect of 2Hz EA on pain-related behaviors in SNI rats. Administration of 2Hz EA to SNI rats once every other day lasting for 21 days. Expression of spinal protein molecules were detected using Western blot and immunofluorescence staining.ResultsIt was found that SNI significantly induced mechanical hypersensitivity and decrease of gait parameters, and subsequently increased the levels of HMGB1, TLR4, MyD88, and NF-κB p65 protein expression. 2Hz EA stimulation led to remarkable attenuation of mechanical hypersensitivity, upregulation of spinal HMGB1, TLR4, MyD88, and NF-κB p65 protein expressions induced by SNI, and significant improvement in gait parameters. Furthermore, immunofluorescence staining also confirmed that 2Hz EA obviously suppressed the co-expression of microglia activation marker CD11b and TLR4 or MyD88, as well as the activation of NF-κB p65 in SNI rats.ConclusionThis study suggested that blockade of HMGB1/NF-κB signaling in the spinal cord may be a promising therapeutic approach for 2Hz EA management of SNI-induced neuropathic pain.

Lower frequency electroacupuncture is better in promoting recovery of limb locomotion in rats with sciatic nerve injury by reducing local inflammatory reaction

To observe the effect of different frequencies (2 Hz, 100 Hz) of electroacupuncture (EA) on limb locomotion and the expression of inflammatory factors IL-1β, IL-6, TNF-α in sciatic nerve, and nuclear factor kappa B (NF-κB) in lumber(L)4-L5of spinal cord in rats with sciatic nerve injury (SNI), so as to reveal its mechanisms underlying improvement of SNI. A total of 48 SD rats (half male and half female) were equally divided into blank control, model, low frequency (2 Hz) EA and high frequency (100 Hz) EA groups. The SNI model was established by clamping the spinal nerve. EA intervention (2 Hz, 100 Hz, 1 mA), starting on the 8th day after modeling, was applied to "Huantiao" (GB30) on the injured side for 15 min, once daily for 14 consecutive days. The sciatic function index (SFI) was calculated to assess the injured hindlimb recovery with reference to BAIN's and colleagues' methods. Histopathological changes of the sciatic nerve were displayed by H.E. staining. The expressions of IL-1β, IL-6 and TNF-α in the sciatic nerve tissue were detected by immunohistochemistry, and the expression of NF-κB in the spinal cord was detected by using Western blot. After modeling, the SFI level on day 8 was significantly decreased in the model group (P<0.01), and no significant differences were found among the model, low frequency EA and high frequency EA groups before the EA intervention (P>0.05). Following the treatment (at the 22nd day), the SFI values of both low frequency EA and high frequency EA groups were significantly increased (P<0.01), suggesting an improvement of the limb motor function, and the SFI of the low frequency EA group was notably higher than that of the high frequency EA group (P<0.01). In comparison with the blank control group, the expression levels of IL-1β, IL-6, TNF-α in the sciatic nerve and NF-κB protein in the spinal cord were significantly up-regulated (P<0.05). Following EA intervention, the increased expression levels of IL-1β, IL-6, TNF-α and NF-κB proteins were significantly down-regulated in both low frequency EA and high frequency EA groups (P<0.05), and the therapeutic effect of low frequency EA was markedly superior to that of high frequency EA in down-regulating the expression levels of IL-1β, IL-6, TNF-α and NF-κB protein (P<0.05). H.E. staining showed increase of Schwann cells in number, cellular swelling, and disintegration of the axons and myelin sheath, and appearance of vacuolar degeneration in the model group, which was relatively milder in both low frequency EA and high frequency EA groups, particularly in the low frequency EA group. EA of GB30 at 2 Hz and 100 Hz can promote the recovery of hindlimb motor function in SNI rats, which is probably related to its function in inhibiting the inflammatory response, and facilitating the repair of the damaged sciatic nerve. 2 Hz EA is better than 100 Hz EA in the therapeutic effect.

Electroacupuncture Stimulation Alleviates CFA-Induced Inflammatory Pain Via Suppressing P2X3 Expression.

Chronic inflammatory pain is one of the most common complaints that seriously affects patients’ quality of life. Previous studies have demonstrated that the analgesic effect of electroacupuncture (EA) stimulation on inflammatory pain is related to its frequency. In this study, we focused on whether the analgesic effects of EA are related to the period of stimulation. Purinergic receptor P2X3 (P2X3) is involved in the pathological process underlying chronic inflammatory pain and neuropathic pain. We hypothesized that 100 Hz EA stimulation alleviated Freund’s complete adjuvant (CFA) induced inflammatory pain via regulating P2X3 expression in the dorsal root ganglion (DRG) and/or spinal cord dorsal horn (SCDH). We also assumed that the analgesic effect of EA might be related to the period of stimulation. We found that both short-term (three day) and long-term (14 day) 100 Hz EA stimulation effectively increased the paw withdrawal threshold (PWT) and reversed the elevation of P2X3 in the DRG and SCDH of CFA rats. However, the analgesic effects of 100 Hz EA were not dependent on the period of stimulation. Moreover, P2X3 inhibition or activation may contribute to or attenuate the analgesic effects of 100 Hz EA on CFA-induced inflammatory pain. This result indicated that EA reduced pain hypersensitivity through P2X3 modulation.