Somatosensory Nerve Fibers Mediated Generation of De-qi in Manual Acupuncture and Local Moxibustion-Like Stimuli-Modulated Gastric Motility in Rats

Objectivization study of acupuncture Deqi and brain modulation mechanisms: a review

Deqi is an important prerequisite for acupuncture to achieve optimal efficacy. Chinese medicine has long been concerned with the relationship between Deqi and the clinical efficacy of acupuncture. However, the underlying mechanisms of Deqi are complex and there is a lack of systematic summaries of objective quantitative studies of Deqi. Acupuncture Deqi can achieve the purpose of treating diseases by regulating the interaction of local and neighboring acupoints, brain centers, and target organs. At local and neighboring acupoints, Deqi can change their tissue structure, temperature, blood perfusion, energy metabolism, and electrophysiological indicators. At the central brain level, Deqi can activate the brain regions of the thalamus, parahippocampal gyrus, postcentral gyrus, insular, middle temporal gyrus, cingulate gyrus, etc. It also has extensive effects on the limbic-paralimbic-neocortical-network and default mode network. The brain mechanisms of Deqi vary depending on the acupuncture techniques and points chosen. In addition, Deqi 's mechanism of action involves correcting abnormalities in target organs. The mechanisms of acupuncture Deqi are multi-targeted and multi-layered. The biological mechanisms of Deqi are closely related to brain centers. This study will help to explore the mechanism of Deqi from a local-central-target-organ perspective and provide information for future clinical decision-making.

Effects and mechanisms of acupuncture analgesia mediated by afferent nerves in acupoint microenvironments

In the past few decades, the use of acupuncture analgesia in clinical practice has increased worldwide. This is due to its various benefits, including natural alleviation of pain without causing various adverse effects associated with non-steroidal anti-inflammatory drugs (NSAID) and opioids. The acupoint represents the initial site of acupuncture stimulation, where diverse types of nerve fibers located at the acupoint hold significant roles in the generation and transmission of acupuncture-related information. In this study, we analyzed the patterns and mechanisms of acupuncture analgesic mediated by acupoint afferent fibers, and found that acupuncture stimulates acupoints which rapidly and directly induces activation of high-density primary afferent fibers under the acupoints, including myelinated A fibers and unmyelinated C fibers. During acupuncture stimulation at the muscle layer, the analgesic effects can be induced by stimulation of A fiber threshold intensity. At the skin layer, the analgesic effects can only be produced by stimulation of C fiber threshold intensity. Electroacupuncture (EA) activates A fibers, while manual acupuncture (MA) activates both A and C fibers. Furthermore, acupuncture alters acupoint microenvironments, which positively modulates afferent fibers, enhancing the transmission of analgesic signals. In addition to local activation and conduction at acupoints, nerve fibers mediate the transmission of acupuncture information to pain centers. In the spinal cord, acupuncture activates neurons by inducing afferent fiber depolarization, modulating pain gating, inhibiting long-term potentiation (LTP) of the spinal dorsal horn and wide dynamic range (WDR) neuronal activities. At higher nerve centers, acupuncture inhibits neuronal activation in pain-related brain regions. In summary, acupuncture inhibits pain signal transmission at peripheral and central systems by activating different patterns of afferent fibers located on various layers of acupoints. This study provides ideas for enhancing the precise application and clinical translation of acupuncture.

Effectiveness of acupuncture for postoperative gastrointestinal recovery in patients undergoing thoracoscopic surgery: a prospective randomized controlled study

BACKGROUND

Postoperative gastrointestinal dysfunction (PGD) is one of the most common complications among patients who have undergone thoracic surgery. Acupuncture has long been used in traditional Chinese medicine to treat gastrointestinal diseases and has shown benefit as an alternative therapy for the management of digestive ailments. This study aimed to explore the therapeutic effectiveness of acupuncture as a means to aid postoperative recovery of gastrointestinal function in patients undergoing thoracoscopic surgery.

METHODS

In total, 112 patients aged 18-70 years undergoing thoracoscopic surgery between 15 June 2022 and 30 August 2022 were randomized into two groups. Patients in the acupuncture group (AG) first received acupuncture treatment 4 h after surgery, and treatment was repeated at 24 and 48 h. Patients in the control group (CG) did not receive any acupuncture treatment. Both groups received the same anesthetic protocol. Ultrasound-guided thoracic paravertebral block (TPVB) was performed in the paravertebral spaces between T4 and T5 with administration of 20 mL of 0.33% ropivacaine. All patients received patient-controlled intravenous analgesia (PCIA) after surgery.

RESULTS

Median time to first flatus [interquartile range] in the AG was significantly less than in the CG (23.25 [18.13, 29.75] vs 30.75 [24.13, 45.38] h, p < 0.001). Time to first fluid intake after surgery was significantly less in the AG, as compared with the CG (4 [3, 7] vs 6.5 [4.13, 10.75] h, p = 0.003). Static pain, measured by visual analog scale (VAS) score, was significantly different on the third day after surgery (p = 0.018). Dynamic pain VAS scores were lower in the AG versus CG on the first three postoperative days (p = 0.014, 0.003 and 0.041, respectively).

CONCLUSION

Addition of acupuncture appeared to improve recovery of postoperative gastrointestinal function and alleviate posteoperative pain in patients undergoing thoracoscopic surgery. Acupuncture may represent a feasible strategy for the prevention of PGD occurrence.

TRIAL REGISTRATION NUMBER

ChiCTR2200060888 (Chinese Clinical Trial Registry).

Potential mechanisms of acupuncture for neuropathic pain based on somatosensory system

Neuropathic pain, caused by a lesion or disease of the somatosensory system, is common and distressing. In view of the high human and economic burden, more effective treatment strategies were urgently needed. Acupuncture has been increasingly used as an adjuvant or complementary therapy for neuropathic pain. Although the therapeutic effects of acupuncture have been demonstrated in various high-quality randomized controlled trials, there is significant heterogeneity in the underlying mechanisms. This review aimed to summarize the potential mechanisms of acupuncture on neuropathic pain based on the somatosensory system, and guided for future both foundational and clinical studies. Here, we argued that acupuncture may have the potential to inhibit neuronal activity caused by neuropathic pain, through reducing the activation of pain-related ion channels and suppressing glial cells (including microglia and astrocytes) to release inflammatory cytokines, chemokines, amongst others. Meanwhile, acupuncture as a non-pharmacologic treatment, may have potential to activate descending pain control system via increasing the level of spinal or brain 5-hydroxytryptamine (5-HT), norepinephrine (NE), and opioid peptides. And the types of endogenously opioid peptides was influenced by electroacupuncture-frequency. The cumulative evidence demonstrated that acupuncture provided an alternative or adjunctive therapy for neuropathic pain.

Temperature Characteristics of Traditional Indirect Moxibustion and Electronic Moxibustion

Background

Electronic moxibustion (EM) was developed to minimize the side effects of traditional moxibustion, such as burns, and to overcome therapeutic compliances such as smoke or smell.

Objectives

To investigate distributions and thermal stimulation of EM at various depths using silicon phantom and to compare this methodology to traditional indirect moxibustion (TIM).

Methods

A silicon phantom composed of polydimethylsiloxane was heated and immersed in a hot plate containing warm water to set the phantom's temperature to that of biological tissue. K-type thermocouples were inserted into the phantom at depths of 0, 2, 5, 7, and 10 mm to measure temperature changes with thermal stimulation of EM or TIM placed on top of the phantom.

Results

At the surface of the phantom, the peak temperature after applying TIM (55.04 ± 0.92℃ [Δ23.79 ± 0.96℃]) was significantly higher than after EM (43.25 ± 1.95℃ [Δ13.00 ± 2.23℃]), with both interventions reaching the highest temperature after 2 minutes. The temperature increase for TIM was also statistically significant compared to EM when measured at a depth of 2 mm. For the experimental setting with TIM, after reaching peak surface temperature, a rapid decrease was observed at the surface and 2 mm while EM showed a much more gradual decline. There was no significant difference in temperature change between the groups at depths of 5, 7, and 10 mm.

Conclusion

TIM resulted in a higher temperature rise compared to EM at the surface and at a 2 mm depth reaching over 50℃, which creates risk of burns. Thermal stimulation with EM had a lower risk of burns with temperature increment not being statistically different from TIM below the depth of 5 mm.

Involvement of Neuropeptide Y within Paraventricular Nucleus in Electroacupuncture Inhibiting Sympathetic Activities in Hypertensive Rats

Although electroacupuncture (EA) has been used to decrease the blood pressure (BP) clinically, the underlying mechanisms are not clearly clarified. This study aimed to assess the hypothesis that EA treatment exerts a hypotensive action via suppressing sympathetic activities and modulating neuropeptide Y (NPY) function within the paraventricular nucleus (PVN) of hypertensive rats. Male Sprague-Dawley rats were selected for the experiment, and the hypertensive models were established by the two-kidney, one-clip (2K1C) method. Then, the rats were randomly assigned to the sham group, 2K1C group, 2K1C plus EA group, and 2K1C plus sham EA group. EA treatment at the acupoints ST36 and ST40 overlying the peroneal nerves was given once a day for 30 days. The radiotelemetry system was applied to collect the arterial BP recordings. Power spectral analyses of BP variability, BP responses to ganglionic blockade, and plasma levels of norepinephrine and epinephrine were performed to assess the changes in sympathetic nerve activity. Real-time PCR and Western blots were carried out to examine the expression of NPY system in the PVN. The responses of PVN microinjection with NPY Y1R antagonist BIBO3304 were detected to check the endogenous NPY tone. The results showed that the enhanced arterial BP and sympathetic activities were effectively reduced by 30 days of EA treatment, and baroreflex sensitivity was improved in 2K1C hypertensive rats. The level of NPY mRNA and protein expression in the PVN was markedly upregulated by EA treatment in 2K1C rats. In addition, the pressor responses of PVN microinjection with NPY Y1R antagonist BIBO3304 in 2K1C models were remarkably augmented by the EA stimulation. Our results indicate that the increased NPY expression and function in the PVN induced by EA treatment contribute to antihypertensive and sympathetic suppression on hypertensive rats. The findings may elucidate the underlying mechanisms of the acupuncture to be a potential therapeutic strategy against hypertension.

Pilot Study of Acupuncture's Antispasmodic Effect on Upper Gastrointestinal Tract during Endoscopic Submucosal Dissection for Early Gastric Cancer: Controlled Clinical Trial

A prospective study was conducted in patients with early-stage gastric cancer to determine the efficacy and safety of acupuncture stimulation as an antispasmodic compared with conventional medication during the procedure of endoscopic submucosal dissection (ESD) of the upper gastrointestinal tract. This study was a prospective single blinded quasi-randomized controlled trial. Seventy-three patients who were scheduled to undergo ESD for gastric cancer at Aizu Medical Center between 19 February 2016 and 30 June 2016 were assessed for eligibility for the study. Sixty out of 73 patients were included in the study and assigned into two intervention groups: medication group (MG) and acupuncture group (AG). Ease of the procedure was evaluated using modified NIWA classification (MNC) by endoscopist considering the frequency and amplitude of the upper gastrointestinal peristalsis. For the statistical analysis, Mann-Whitney test was used to compare the differences of MNC values (baseline and end of procedure) between two groups. The difference of MNC found in the AG (-2.00 (-3.0 to -2.0)) was significantly greater than that in the MG (-1.00 (-2.0 to -1.0), p < 0.0001, Mann-Whitney test). We consider that acupuncture to the abdomen could be an alternative antispasmodic method during upper gastrointestinal endoscopic procedure.

Effects of Moxibustion on Stress-Induced Delayed Gastric Emptying via Somatoautonomic Reflex in Rats

Objective: Moxibustion (MOX) is used to treat a wide variety of disorders, including those with gastric symptoms. However, the exact mechanisms underlying the beneficial effects of MOX are unknown. The purpose of this study was to investigate if application of indirect MOX (iMOX) to ST 36 reduces restraint stress (RS)-induced alteration in gastric responses of conscious rats, and if a somatoautonomic reflex mediates gastric emptying (GE). Materials and Methods: One group of rats was fed solid food after 24 hours of fasting. Immediately after food ingestion. These rats were subjected to RS. Ninety minutes after feeding, the rats were euthanized, and their gastric contents were removed to calculate GE. iMOX had been performed at ST 36 bilaterally throughout the stress loading. To investigate if vagal-nerve activity was involved in mediating the stress-induced alterations of GE by iMOX, atropine was intraperitoneally administered to other rats just before initiating RS; bilateral truncal vagotomy had been performed on day 14 before GE measurement. Results: RS delayed GE significantly (42.9 ± 5.8%)in stressed rats, compared to nonstressed rats (68.7 ± 1.8%). iMOX at ST 36 reduced stress-induced inhibition of GE significantly (67.1 ± 2.4%). MOX-mediated reduction of GE disappeared upon atropine injection and vagotomy. Conclusions: RS-induced delayed GE may be ameliorated by iMOX at ST 36. Somatoautonomic, reflex-induced vagal-nerve activity helps mediate the stimulatory effects of iMOX on RS-induced delayed GE. As a complementary and alternative medicine, iMOX may also be advantageous for patients with gastric disorders, such as functional dyspepsia.

Neuromechanism of acupuncture regulating gastrointestinal motility

Acupuncture has been used in China for thousands of years and has become more widely accepted by doctors and patients around the world. A large number of clinical studies and animal experiments have confirmed that acupuncture has a benign adjustment effect on gastrointestinal (GI) movement; however, the mechanism of this effect is unclear, especially in terms of neural mechanisms, and there are still many areas that require further exploration. This article reviews the recent data on the neural mechanism of acupuncture on GI movements. We summarize the neural mechanism of acupuncture on GI movement from four aspects: acupuncture signal transmission, the sympathetic and parasympathetic nervous system, the enteric nervous system, and the central nervous system.

Effects of Three Needling Manipulations of Zusanli (ST 36) on Deqi Sensations and Surface Myoelectricity in Healthy Participants

OBJECTIVE

To investigate the effects of different acupuncture manipulations on Deqi sensations and surface myoelectricity, and explore the correlation between Deqi sensations and needling manipulations.

METHODS

Forty-five healthy participants accepted twirling, lifting-thrusting, and twirling plus lifting-thrusting manipulanions at right Zusanli (ST 36), respectively. The acupuncturist's and participants' Deqi sensations were collected by MGH Acupuncture Sensation Scale (MASS). The intensity and occurrence rate of soreness, dull pain, pressure, heaviness, fullness, numbness, sharp pain, warmth, coolness, and throbbing feelings of participants, and tightness, smooth, and tangle feelings of acupuncturist were measured. The correlation between the acupuncturist's and participant's Deqi sensations was analyzed. Surface electromyogram (EMG) were recorded before, during and after needling in 30 participants. The integrated EMG (iEMG), mean power frequency (MPF) and media frequency (MF) were analyzed.

RESULT

Both fullness and soreness of participants and tightness of acupuncturist were the most frequently occurred ones. A positive correlation between participants' fullness and acupuncturist's tightness was observed during the three aforementioned needling manipulations (P<0.05, OR>1). Almost all the needling sensations measured in the present study could be induced by the three needling manipulations. However, strength of Deqi sensations was exhibited as lifting-thrusting > twirling plus lifting-thrusting > twirling according to MASS index. The iEMG values were increased and MPF, MF values were decreased during needling compaired to those before needling, especially during lifting-thrusting (P<0.01).

CONCLUSIONS

The intensity and occurrence rate of the different Deqi sensations induced by different needling manipulations were basically similar. The fullness and soreness were both the most frequently induced Deqi sensations. The strongest Deqi sensation could be induced by lifting-thrusting manipulation. There is a positive correlation between participants' fullness and acupuncturist's tightness during the three needling manipulations. The myoelectricity around the acupoint is related to Deqi responses. (Registration No. AMCTR-IOR-20000314).

Moxibustion Modulates Sympathoexcitatory Cardiovascular Reflex Responses Through Paraventricular Nucleus

Electroacupuncture (EA) point specific (ST36-37) stimulation decreases cardiovascular reflex responses through supraspinal regions such as the hypothalamic paraventricular nucleus (PVN) while mechanical stimulation of acupoints decreases pressor responses through peripheral thermal transient receptor potential vanilloid type-1 (TRPV1). Moxibustion generating heat applied at acupoint in combination with antihypertensive drugs decreases elevated blood pressure. We hypothesized that moxibustion modulates sympathoexcitatory cardiovascular responses through the hypothalamic PVN and peripheral heat sensitive TRPV1 in the absence of antihypertensive drugs. Rats were anesthetized, ventilated, and heart rate and mean blood pressure were monitored. Gastric distention induced consistent pressor reflex responses every 10-min. Thirty-minutes of bilateral moxibustion at the acupoint ST36, overlying the deep peroneal nerves, reduced the gastric distention evoked elevation in blood pressure. Blood pressure reflex responses were not reduced by both EA and moxibustion at G39. The moxibustion inhibition but not EA inhibition of the cardiovascular responses was reversed with blockade of local heat sensitive TRPV1 at ST36. Accordingly, activation of thermal TRPV1 by moxibustion at an average of 44.2°C in contrast to 40°C reduced the pressor responses. Naloxone, an opioid receptor antagonist, microinjected into PVN inhibited transiently the effect of moxibustion. Thus, activation of peripheral heat sensitive TRPV1 mediated the moxibustion-inhibition, but not EA-inhibition, of sympathoexcitatory cardiovascular reflex responses through hypothalamic PVN opioid system.

Effect of Different Dosages of ST36 Indirect Moxibustion on the Skin Temperature of the Lower Legs and Feet

Background: Indirect moxibustion (IM) has been previously performed between the spinous process while recording skin temperature of the trunk. However, moxibustion is often applied not only to acupuncture points on the back, but also to points located on the limbs. Thus, there is a need to investigate skin temperature (ST) responses following IM applied to the limbs. Methods: In Experiment 1 (Exp 1), subjects were randomly assigned to three groups: the left IM stimulation, right IM stimulation and control groups. In Experiment 2 (Exp 2), the subjects underwent two experimental sessions consisting of a single stimulation of IM or triple stimulations of IM. The IM stimulation was administered to the ST36 acupuncture point. A thermograph was used to obtain the ST on the lower limbs. Results: In Exp 1, the ST of the lower limbs increased in the stimulation groups whereas there was no increase in the non-stimulation group. In Exp 2, no significant response occurred between the single and triple stimulation of IM groups for all observed sites except for the left ankle ST. Conclusions: Lower limb ST increased following IM application to the ST36 point. No difference was observed between the dosage of the stimulation and ST responses.

Using the "target constituent removal combined with bioactivity assay" strategy to investigate the optimum arecoline content in charred areca nut

Charred areca nut (CAN) is used to treat dyspepsia and abdominal distension in children. However, reports revealed that arecoline, the most important active constituent of CAN, possesses potential toxicities. This study was designed to investigate the optimum arecoline content in CAN, using the "target constituent removal combined with bioactivity assay" strategy. Based on PTLC method, we prepared CAN lacking all arecoline (WAC-100R) and a series of different ratios of arecoline-removed CAN samples (WAC-Rx). MTT and acute toxicity assays indicated that decreasing content by 50% decreased CAN toxicity significantly. Animal results revealed arecoline contents over 50% could guarantee the beneficial effects of CAN on gastrointestinal tract. Additionally, decreasing arecoline content in CAN by 50% decreased its pro-apoptotic effects significantly. Furthermore, decreasing 50% arecoline content in CAN down-regulated the expressions of Cleaved-Caspase-3, c-jun, c-fos, COX-2, PGE2, and IL-1α. Thus, our results revealed that CAN with 50% arecoline content (WAC-50R) has similar beneficial effects on the gastrointestinal tract to CAN, whereas its toxicity was decreased significantly. Collectively, our study suggested that the strategy of "target constituent removal combined with bioactivity assay" is a promising method to identify the optimum arecoline content in CAN, which is approximately 0.12%.

Acupuncture and regulation of gastrointestinal function

In China, acupuncture has been considered an effective method for treating gastrointestinal (GI) dysfunction diseases for thousands of years. In fact, acupuncture has gained progressive acceptance from both practitioners and patients worldwide. However, the therapeutic effects and underlying mechanisms in treating GI dysfunction have not yet been established due to a lack of systematic and comprehensive review articles. Therefore, the aim of this review is to discuss the efficacy of acupuncture as a treatment for GI dysfunction and the associated underlying mechanisms. A search of PubMed was conducted for articles that were published over the past 10 years using the terms “acupuncture”, “gastrointestine”, and other relevant keywords. In the following review, we describe the effect and underlying mechanisms of acupuncture on GI function from the perspectives of GI motility, visceral sensitivity, the GI barrier, and the brain-gut axis. The dual regulatory effects of acupuncture may manifest by promoting gastric peristalsis in subjects with low initial gastric motility, and suppressing peristalsis in subjects with active initial motility. In addition, the regulation of acupuncture on gastric motility may be intensity-dependent. Our findings suggest that further studies are needed to investigate the effects and more systematic mechanisms in treating GI dysfunction, and to promote the application of acupuncture for the treatment of GI diseases.

Differential effects of variable frequencies of manual acupuncture at ST36 in rats with atropine-induced inhibition of gastric motility

OBJECTIVE

The 'intensity-response' relationship between acupuncture stimulation and therapeutic effect is currently the focus of much research interest. The same needling manipulation with different frequencies can generate differential levels of stimulus. This study aimed to examine the effects on gastric motility induced by four twirling frequencies based on relatively standardised manual acupuncture (MA) manipulations.

METHODS

Twirling manipulations at 1, 2, 3, and 4 Hz were practised before the experiments by a single operator using an MA parameter measurement device and stability was evaluated through time-frequency analysis. Forty-eight Sprague-Dawley rats were randomly divided into six groups (n=8 each): Control, Model, Model+MA (1, 2, 3, and 4 Hz). Rats in the five Model groups received injections of atropine into the tail vein to inhibit gastric motility, which was continuously recorded by a balloon in the gastric antrum. Rats in the four Model+MA groups received MA at 1, 2, 3 and 4 Hz, respectively, for 70 s and needles were retained for a further 5 min.

RESULTS

The amplitude of waveforms produced by the four twirling frequencies was relatively consistent and reproducible. The gastric motility amplitude in all groups decreased after modelling (injections of atropine) (p<0.01). Twirling manipulation at 1, 2, and 3 Hz (but not 4 Hz) increased gastric motility amplitude (p<0.05). The increase in gastric motility amplitude induced by MA at 2 Hz was greater than for all other frequencies (p<0.05).

CONCLUSIONS

Acupuncture at ST36 helped recover gastric motility amplitude in rats with atropine-induced gastric inhibition and the effects induced by 1-3 Hz frequency were greater than those induced by 4 Hz.

Acupoint Activation: Response in Microcirculation and the Role of Mast Cells

BACKGROUND

According to Traditional Chinese Medicine (TCM) theory, acupuncture effects are based on the integrity function of meridians. Meridians are thought to regulate body function through the normal flow of qi and/or blood. Disturbances in this flow are thought to cause disease, and acupuncture techniques are believed to cure disease by regulating this flow. However, it is still difficult to understand the exact meaning of qi and to evaluate the activation of meridians. Thus, more and more attention has been focused on the relationship of acupuncture and circulation.

METHODS

In this narrative review, the authors focus on the state of the art in acupoint activation, microcirculation response, and on investigation of mast cells, based on current literature research.

RESULTS

Altogether, 52 references are cited and discussed critically. A schematic diagram of the relationship between acupuncture stimulation, changes of microcirculation and mast cells is presented as result.

CONCLUSION

The block diagram presented in this review article shows that mast cells might play an important role in circulation response after acupoint stimulation.