Acupuncture alleviates chronic pain and comorbid conditions in a mouse model of neuropathic pain: the involvement of DNA methylation in the prefrontal cortex.

ABSTRACT: Chronic pain reduces life quality and is an important clinical problem associated with emotional and cognitive dysfunction. Epigenetic regulation of DNA methylation is involved in the induction of abnormal behaviors and pathological gene expression. We examined whether acupuncture can restore epigenetic changes caused by chronic pain, and identified the underlying mechanisms in neuropathic pain mice. Acupuncture treatment for 6 months (3 days/week) improved mechanical/cold allodynia and the emotional/cognitive dysfunction caused by left partial sciatic nerve ligation (PSNL)-induced neuropathic pain. The effects of acupuncture were associated with global DNA methylation recovery in the prefrontal cortex (PFC). Analysis of DNA methylation patterns in PFC indicated that 1364 overlapping genes among 4442 and 4416 methylated genes in the PSNL vs sham and PSNL vs acupuncture points groups, respectively, were highly associated with the DNA methylation process. Acupuncture restored the reduced expression of 5-methylcytosine, methyl-cytosine-phospho-guanine binding protein 2, and DNA methyltransferase family enzymes induced by PSNL in PFC. Methylation levels of Nr4a1 and Chkb associated with mitochondrial dysfunction were decreased in PFC of the PSNL mice, and increased by acupuncture. By contrast, high expression of Nr4a1 and Chkb mRNA in PSNL mice decreased after acupuncture. We also found that acupuncture inhibited the expression of Ras pathway-related genes such as Rasgrp1 and Rassf1. Finally, the expression of Nr4a1, Rasgrp1, Rassf1, and Chkb mRNA increased in the neuronal cells treated with Mecp2 small interfering RNA. These results suggest that acupuncture can relieve chronic pain-induced comorbid conditions by altering DNA methylation of Nr4a1, Rasgrp1, Rassf1, and Chkb in the PFC.

Brain functional connectivity changes by low back extension pain model in low back pain patients.

PURPOSE: Low back pain (LBP) is a common ailment in most developed countries. Because most cases of LBP are known as 'non-specific', it has been challenging to develop experimental pain models of LBP which reproduce patients' clinical pain. In addition, previous models have limited applicability in a steady-pain-state neuroimaging environment. Thus, this study aims to devise a low back pain model with a simple methodology to induce experimental LBP, which has similar pain properties to patients' clinical pain, and to apply the model in a steady-pain-state neuroimaging study. METHODS: Our low back extension (LBE) pain model was tested on 217 LBP patients outside the magnetic resonance imaging (MRI) scanner to determine the reproducibility of endogenous pain and the similarity to their own clinical pain (STUDY1), and applied in a steady-pain-state functional MRI study (47 LBP patients and 23 healthy controls) to determine its applicability (induced head motions and brain functional connectivity changes; STUDY2). RESULTS: By the LBE pain model, 68.2% of the LBP patients reported increased LBP with high similarity of sensations to their own clinical pain (STUDY1), and the head motions were statistically similar to and correlated with those in resting state (STUDY2). Furthermore, the LBE model altered brain functional connectivity by decreasing the default-mode and the sensorimotor networks, and increasing the salience network, which was significantly associated with the intensity of the induced pain. Conversely, the healthy controls showed increased somatosensory network (but not of the cognitive pain processing). CONCLUSION: Our investigations suggest that our LBE pain model, which increased LBP with high similarity to the LBP patients' own pain sensation and induced patient-specific brain responses with acceptable head motion, could be applied to neuroimaging studies investigating brain responses to different levels of endogenous LBP.

Acupuncture Improves Comorbid Cognitive Impairments Induced by Neuropathic Pain in Mice.

Growing evidence indicates that neuropathic pain is frequently accompanied by cognitive impairments, which aggravate the quality of life of chronic pain patients. Here, we investigated whether acupuncture treatments can improve cognitive dysfunction as well as allodynia induced by neuropathic pain in mice. One week after the left partial sciatic nerve ligation (PSNL), acupuncture treatments on the acupoints GB30-GB34 (AP1), HT7-GV20 (AP2), or control points (CP) were performed for 4 weeks. Notably, the significant attenuations of mechanical allodynia and cognitive impairment were observed in the AP1 group, but not in PSNL, AP2, or CP groups. A random decision forest classifier based on the pain and cognitive functions displayed that the acupuncture group was clearly segregated from the other groups. We also demonstrated that acupuncture restored the reduced field excitatory post-synaptic potentials and was able to elevate the expression levels of glutamate receptors (NR2B and GluR1) in the hippocampus. Moreover, the expressions of Ca2+/calmodulin-dependent protein kinase II and synaptic proteins (pPSD-95 and pSyn-1) were enhanced by acupuncture treatment. These results suggest that acupuncture can enhance hippocampal long-term action through the regulation of the synaptic efficacy and that acupuncture may provide a viable option for managing both pain and cognitive functions associated with chronic neuropathic pain.

Effect and neurophysiological mechanism of acupuncture in patients with chronic sciatica: protocol for a randomized, patient-assessor blind, sham-controlled clinical trial.

BACKGROUND: Sciatica is a relatively frequent illness that easily becomes a chronic and relapsing condition. Although numerous systematic reviews have analyzed various therapies for sciatica, the validity of their included studies is limited. Considering the limitations of conventional treatment options for sciatica, acupuncture is a possible option; however, evidence supporting its efficacy and mechanism in patients with sciatica is lacking. The aim of this proposed protocol is to investigate the effect and neurophysiological mechanism of acupuncture in patients with chronic sciatica. METHODS/DESIGN: This study is a randomized, patient-assessor blind, two-arm, parallel, non-penetrating, sham-controlled clinical trial. Eligible participants will include adults (aged 19-70 years old) with a clinical diagnosis of chronic sciatica (40 mm or more of a 100-mm visual analog scale (VAS) for bothersomeness) blinded to the treatment received. Patients will be randomly allocated into the acupuncture treatment group (manual acupuncture plus electroacupuncture (EA), n = 34) or the sham acupuncture control group (sham acupuncture plus placebo EA without electrical stimulation, n = 34). Groups will receive treatment twice a week for a total of eight sessions over 4 weeks. Functional magnetic resonance imaging will be implemented at baseline and endpoint to investigate the mechanism of acupuncture. The primary outcome measure is the VAS for bothersomeness and secondary outcomes include the VAS for pain intensity, Oswestry Disability Index, EuroQol 5-Dimension, Coping Strategy Questionnaire, Beck's Depression Inventory, and State-Trait Anxiety Inventory. Adverse events will be assessed at every visit. DISCUSSION: The results of this trial (which will be available in 2020) should provide important clinical evidence for the effect of acupuncture and demonstrate how acupuncture can be helpful for the treatment of chronic sciatica. TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT03350789 . Registered on 15 November 2017.

Bee venom acupuncture for the treatment of chronic low back pain: study protocol for a randomized, double-blinded, sham-controlled trial.

BACKGROUND: Chronic non-specific low back pain is the most common medical problem for which patients seek complementary and alternative medical treatment, including bee venom acupuncture. However, the effectiveness and safety of such treatments have not been fully established by randomized clinical trials. The aim of this study is to determine whether bee venom acupuncture is effective for improving pain intensity, functional status and quality of life of patients with chronic non-specific low back pain. METHODS/DESIGN: This study is a randomized, double-blinded, sham-controlled clinical trial with two parallel arms. Fifty-four patients between 18 and 65 years of age with non-radicular chronic low back pain experiencing low back pain lasting for at least the previous three months and ≥ 4 points on a 10-cm visual analog scale for bothersomeness at the time of screening will be included in the study. Participants will be randomly allocated into the real or sham bee venom acupuncture groups and treated by the same protocol to minimize non-specific and placebo effects. Patients, assessors, acupuncturists and researchers who prepare the real or sham bee venom acupuncture experiments will be blinded to group allocation. All procedures, including the bee venom acupuncture increment protocol administered into predefined acupoints, are designed by a process of consensus with experts and previous researchers according to the Standards for Reporting Interventions in Clinical Trials of Acupuncture. Bothersomeness measured using a visual analogue scale will be the primary outcome. Back pain-related dysfunction, pain, quality of life, depressive symptoms and adverse experiences will be measured using the visual analogue scale for pain intensity, the Oswestry Disability Index, the EuroQol 5-Dimension, and the Beck's Depression Inventory. These measures will be recorded at baseline and 1, 2, 3, 4, 8 and 12 weeks. DISCUSSION: The results from this study will provide clinical evidence on the efficacy and safety of bee venom acupuncture in patients with chronic non-specific low back pain. TRIAL REGISTRATION: This study is registered with the United States National Institutes of Health Clinical Trials Registry: NCT01491321.