Effects of acupuncture at GV01 on experimentally induced colitis in rats: possible involvement of the opioid system

Electroacupuncture Reduces Inflammatory Bowel Disease in Obese Mice by Activating the Nrf2/HO-1 Signaling Pathways and Repairing the Intestinal Barrier

Background

Electroacupuncture (EA) is used to treat inflammatory bowel disease (IBD). Nevertheless, the precise mechanisms by which this approach safeguards against obesity-induced intestinal barrier damage has not been fully understood.

Objective

This study aimed to assess whether EA could ameliorate intestinal barrier damage that had been reversed in a mouse model of obesity induced by a high-fat diet (HFD) and whether this repair is correlated with ferroptosis and gut microbiota enhancement.

Methods

To assess the potential of EA to prevent obesity and restore the intestinal barrier, we divided in C57BL/6J mice into two groups; one was fed with HFD and another one with a normal diet. Samples of stool, blood, fat, and intestinal epithelium were then evaluated, along with body weight.

Results

Following EA, we observed a significant reduction in body weight, fat accumulation, and serum triglyceride (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C) levels; an increase was seen in high-density lipoprotein cholesterol (HDL-C) levels. EA also activated the Nrf2 signaling pathway; upregulated the expression of GPX4, FTH1, and SLC7A11; and downregulated the expression of TFR1. In addition, the administration of EA resulted in a notable modification of the gut microbiota composition, characterized by a decrease in the Firmicutes to Bacteroidetes ratio.

Conclusion

EA had beneficial effects on weight loss and showed potential ability to repair the intestinal barrier by activating the Nrf2 signaling pathway, inhibiting intestinal inflammation and ferroptosis, and regulating the intestinal microbiota to treat IBD caused by HFD-induced obesity.

Electroacupuncture Reduces Visceral Pain Via Cannabinoid CB2 Receptors in a Mouse Model of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) results in chronic abdominal pain in patients due to the presence of inflammatory responses in the colon. Electroacupuncture (EA) is effective in alleviating visceral pain and colonic inflammation associated with IBD. Cannabinoid CB2 receptor agonists also reduce colonic inflammation in a mouse model of IBD. However, whether EA reduces visceral pain and colonic inflammation via the CB2 receptor remains unknown. Here, we determined the mechanism of the antinociceptive effect of EA in a mouse model of IBD induced by rectal perfusion of 2,4,6-trinitrobenzenesulfonic acid solution (TNBS). EA or sham EA was performed at the bilateral Dachangshu (BL25) point for seven consecutive days. The von Frey and colorectal distension tests were performed to measure mechanical referred pain and visceral pain. Western blotting and immunohistochemistry assays were carried out to determine the expression of IL-1β and iNOS and activation of macrophages in the colon tissues. We found that EA, but not sham EA, attenuated visceral hypersensitivity and promoted activation of CB2 receptors, which in turn inhibited macrophage activation and the expression of IL-1β and iNOS. The effects of EA were blocked by AM630, a specific CB2 receptor antagonist, and by CB2 receptor knockout. Our findings suggest that EA attenuates mechanical allodynia and visceral hypersensitivity associated with IBD by activating CB2 receptors and subsequent inhibition of macrophage activation and expression of IL-1β and iNOS.

Electroacupuncture at Neurogenic Spots in Referred Pain Areas Attenuates Hepatic Damages in Bile Duct-Ligated Rats

Visceral pain frequently produces referred pain at somatic sites due to the convergence of somatic and visceral afferents. In skin overlying the referred pain, neurogenic spots characterized by hyperalgesia, tenderness and neurogenic inflammation are found. We investigated whether neurogenic inflammatory spots function as acupoints in the rat model of bile duct ligation-induced liver injury. The majority of neurogenic spots were found in the dorsal trunk overlying the referred pain and matched with locations of acupoints. The spots, as well as acupoints, showed high electrical conductance and enhanced expression of the neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP). Electroacupuncture at neurogenic spots reduced serum hepatocellular enzyme activities and histological patterns of acute liver injury in bile duct ligation (BDL) rats. The results suggest that the neurogenic spots have therapeutic effects as acupoints on hepatic injury in bile-duct ligated rats.

Current overview of opioids in progression of inflammatory bowel disease; pharmacological and clinical considerations

Inflammatory bowel diseases (IBD) belong to a subgroup of persistent, long-term, progressive, and relapsing inflammatory conditions. IBD may spontaneously develop in the colon, resulting in tumor lesions in inflamed regions of the intestine, such as invasive carcinoma. The benefit of opioids for IBD treatment is still questionable, thereby we investigated databases to provide an overview in this context. This review demonstrates the controversial role of opioids in IBD therapy, their physiological and pharmacological functions in attenuating the IBD symptoms, and in improving inflammatory, oxidative stress, and the quality of life factors in IBD subjects. Data were extracted from clinical, in vitro, and in vivo studies in English, between 1995 and 2019, from PubMed, Google Scholar, Scopus, and Cochrane library. Based on recent reports, there are promising opportunities to target the opioid system and control the IBD symptoms. This study suggests a novel approach for future treatment of functional and inflammatory disorders such as IBD.

Enhanced spinal neuronal responses as a mechanism for increased number and size of active acupoints in visceral hyperalgesia

Acupuncture has been used to treat a variety of illness and involves the insertion and manipulation of needles into specific points on the body (termed “acupoints”). It has been suggested that acupoints are not merely discrete, static points, but can be dynamically changed according to the pathological state of internal organs. We investigated in a rat model of mustard oil (MO)-induced visceral hyperalgesia whether the number and size of acupoints were modified according to the severity of the colonic pain, and whether the changes were associated with enhanced activity of the spinal dorsal horn. In MO-treated rats, acupoints showing neurogenic inflammation (termed “neurogenic spots” or Neuro-Sps) were found both bilaterally and unilaterally on the leg. The number and size of these acupoints increased along with increasing doses of MO. Electroacupuncture of the acupoints generated analgesic effects on MO-induced visceral hypersensitivity. The MO-treated rats showed an increase in c-Fos expression in spinal dorsal horn neurons and displayed increased evoked activity and a prolonged after-discharge in spinal wide dynamic response (WDR) neurons in response to colorectal distension. Increased number and size of neurogenic inflammatory acupoints following MO treatment were reduced by inhibiting AMPA and NMDA receptors in the spinal cord. Our findings suggest that acupoints demonstrate increased number and size along with severity of visceral pain, which may be associated with enhanced neuronal responses in spinal dorsal horn neurons.

Paired mechanical and electrical acupuncture of neurogenic spots induces opioid-mediated suppression of hypertension in rats

While our recent studies have suggested that effective acupoints display neurogenic inflammation and can be identified as neurogenic spots (Neuro-Sps), the optimal stimulation conditions and the underlying mechanisms remain uncharacterized. We developed a combined mechano-electrical acupuncture device (MEA) and examined the effects of acupuncture at Neuro-Sps on systolic blood pressure (BP) in a rat model of immobilization-induced hypertension (IMH) and the mediation of endogenous opioid systems in its effect. Cutaneous neurogenic spots were found mostly in the forelimb. Electrical and mechanical acupuncture of Neuro-Sps increased 22-kHz ultrasonic vocalizations (USVs), c-Fos expression and cell excitability in the midbrain and synergistically alleviated the development of hypertension following immobilization stress, which was prevented by administration of the opioid antagonist naloxone into the rostral ventrolateral medulla (rVLM). These findings suggest that mechanical and electrical stimulation at Neuro-Sps suppresses the development of hypertension via mediation of the endogenous opioid system.

Acupuncture points can be identified as cutaneous neurogenic inflammatory spots

Acupuncture, a traditional medical procedure practised for over 2000 years in Asia, stimulates specific but poorly defined sites called acupoints. To date, no unique anatomical acupoint structures have been found. However, noxious sensory signals from visceral organs produce hypersensitive spots on the skin (neurogenic spots), caused by cutaneous neurogenic inflammation, in the dermatome that overlaps with visceral afferent innervations. Here, we show that an acupoint is one form of neurogenic inflammation on the skin. Various studies have demonstrated that acupoints show mechanical hypersensitivity and have high electrical conductance. Stimulation of acupoints produces needling sensations caused by the activation of small diameter afferent nerve fibres and therapeutic effects on the associated visceral organs, which is likely due to the release of endogenous opioids. The present study provides experimental evidence that neurogenic spots exhibit all the characteristics of the acupoints listed above. In addition, the stimulation of neurogenic spots by electrical, mechanical, or chemical means alleviated pathological conditions in rat colitis and hypertension models via the endogenous opioid system. Our results suggest that acupoints associated with internal organs may be identical to neurogenic inflammatory spots on the skin, which are produced by activation of somatic afferents in abnormal conditions of visceral organs.

Complementary and Alternative Medicines Used by Patients With Inflammatory Bowel Diseases

Patients and physicians often have many questions regarding the role of complementary and alternative medicines (CAMs), or nonallopathic therapies, for inflammatory bowel diseases (IBDs). CAMs of various forms are used by more than half of patients with IBD during some point in their disease course. We summarize the available evidence for the most commonly used and discussed CAMs. We discuss evidence for the effects of herbs (such as cannabis and curcumin), probiotics, acupuncture, exercise, and mind-body therapy. There have been few controlled studies of these therapies, which have been limited by their small sample sizes; most studies have been uncontrolled. In addition, there has been a lack of quality control for herbal preparations. It has been a challenge to design rigorous, randomized, placebo-controlled trials, in part owing to problems of adequate blinding for psychological interventions, acupuncture, and exercise. These barriers have limited the acceptance of CAMs by physicians. However, such therapies might be used to supplement conventional therapies and help ease patient symptoms. We conclude that physicians should understand the nature of and evidence for CAMs for IBD so that rational advice can be offered to patients who inquire about their use. CAMs have the potential to aid in the treatment of IBD, but further research is needed to validate these approaches.

Simple acupoints prescription flow chart based on meridian theory: a retrospective study in 102 dogs

To help the clinicians prescribe acupoints easily and effectively, we developed one simple flow chart to select acupoints. This study aimed to evaluate the usefulness of flow chart to select acupoints in dogs. Total 102 dogs showing intervertebral disc disease (IVDD) (n = 12), vomiting (n = 11), diarrhea (n = 2), abdominal pain (n = 5), cough (n = 66), or epilepsy (n = 6) received acupuncture treatment according to the chart, and its outcomes were evaluated as regards clinical symptoms, duration, treatment numbers, and recovery time. Dogs (8/8) with IVDD from grades I to III recovered over periods of 5 days to 6 weeks after 1–12 treatments, while 1/4 dogs with grade IV recovered over 7 weeks after 15 treatments. Vomiting dogs with acute/subacute (n = 8) and chronic symptoms (n = 3) required about 1 and 7 treatments to recover fully, respectively. All dogs (n = 5) with abdominal pain showed fast relief within 24 hours after acupuncture. Two diarrhea cases recovered over 2–9 days after 1-2 treatments. Fifty-four of 66 coughing dogs were recovered by 1-2 treatments. And 5 of 6 epilepsy dogs under a regular acupuncture treatment had no epileptic episode during followup of 12 months. These results suggest that this flow chart can help the clinicians prescribe acupoints effectively.

Acupuncture at GV01 Relieves Somatic Pain Referred by Colitis in Rats

The present study aimed to expand our previous findings regarding the therapeutic effects and underlying mechanisms of acupuncture at GV01 in colitis. Our results showed that acupuncture at GV01 has antinociceptive effects on referred somatic pain induced by experimental colitis, and that endogenous opioid pathways may mediate these effects.

Endogenous opiates and behavior: 2005

This paper is the 28th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over a quarter-century of research. It summarizes papers published during 2005 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity, neurophysiology and transmitter release (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); immunological responses (Section 17).

Effect of traditional acupuncture on proximal colonic motility in conscious dogs

Acupoints on the Large Intestine Meridian and specific acupoints related with large intestine have been empirically used to treat large intestinal disease. However, the relationship between acupoints related with large intestine and their functions has not been investigated fully. We investigated whether large intestine-related acupoints affect colonic motility in conscious dogs implanted with electrodes at the proximal colon. Manual acupuncture was applied at the following acupoints: 7 main points on the Large Intestine Meridian (LI1, LI2, LI3, LI4, LI5, LI6, and LI11), ST25, BL25 or GV1. Acupuncture at the Large Intestine Meridian acupoints, ST25 and BL25 had no significant effects on the proximal colonic motility. However, acupuncture at GV1 depressed the proximal colonic motility by decreasing the total duration and the frequency of contractile states, which may contribute to the therapeutic effects of GV1. This study also revealed that there was no clear correlation between Large Intestine Meridian and the proximal colonic motility in conscious dogs.

Skin on GV01 acupoint in colonic inflammatory states: tenderness and neurogenic inflammation

GV01 is one of the most effective acupoints to treat diarrhea in humans and animals. The present study showed that skin on the GV01 acupoint reveals tenderness and neurogenic inflammation in colonic inflammatory states, but not in normal healthy states.

The Anti-Inflammatory Effects of Low- and High-Frequency Electroacupuncture Are Mediated by Peripheral Opioids in a Mouse Air Pouch Inflammation Model

BACKGROUND

Although acupuncture has been widely used for complementary therapeutic approaches to treat inflammatory diseases and inflammation-induced pain, the potential anti-inflammatory effects of acupuncture treatment remain controversial in clinical trials, and the underlying mechanisms are still unclear.

OBJECTIVE

The objective was to determine whether electroacupuncture (EA) is able to suppress the peripheral inflammatory response (e.g., zymosan-induced leukocyte migration into air pouch). As part of a mechanistic approach, it was further evaluated whether endogenous opioid systems are involved in the "EA-induced anti-inflammatory effect" (EA-AI).

METHODS

EA (1 or 120 Hz) was performed bilaterally in the Zusanli acupoint (ST36) or in a nonacupoint (gluteal muscle) for 30 min in ICR mice under anesthetic condition. The number of leukocytes that migrated into the air pouch was counted 4 hours after zymosan injection. EA was performed at 0, 0.5, 1, or 2 hours prior to zymosan injection, respectively. To evaluate opioid involvement in EA-AI, intrathecal naloxone (36 microg/mouse) and intraperitoneal naloxone methiodide (30 mg/kg) were administered 10 min before EA stimulation.

RESULTS

Both the 1 and 120 Hz frequencies of EA into Zusanli acupoint at the same time with zymosan injection significantly reduced leukocyte migration into the air pouch as compared with those of control groups (i.e., anesthetic control and needling control into Zusanli acupoint without electrical stimulation). The EA stimulation into nonacupoint did not produce any significant anti-inflammatory effect. EA treatment at 0.5 hours prior to zymosan injection also produced an anti-inflammatory effect but 1 and 2 hours prior to zymosan injection did not elicit any effect. Peripheral opioid blockage significantly reversed EA-AI, whereas spinal opioid blockage did not alter EA-AI.

CONCLUSION

EA can suppress peripheral inflammation through a peripheral opioid mechanism. To achieve the full effectiveness of EA, repeated application is recommended for the treatment of a variety of inflammatory diseases.