Electroacupuncture to ST36 ameliorates behavioral and biochemical responses to restraint stress in rats

Effects of acupuncture on hypothalamic-pituitary-adrenal axis: Current status and future perspectives

The hypothalamic-pituitary-adrenal (HPA) axis is a critical component of the neuroendocrine system, playing a central role in regulating the body's stress response and modulating various physiological processes. Dysregulation of HPA axis function disrupts the neuroendocrine equilibrium, resulting in impaired physiological functions. Acupuncture is recognized as a non-pharmacological type of therapy which has been confirmed to play an important role in modulating the HPA axis and thus favorably targets diseases with abnormal activation of the HPA axis. With numerous studies reporting the promising efficacy of acupuncture for neuroendocrine disorders, a comprehensive review in terms of the underlying molecular mechanism for acupuncture, especially in regulating the HPA axis, is currently in need. This review fills the need and summarizes recent breakthroughs, from the basic principles and the pathological changes of HPA axis dysfunction, to the molecular mechanisms by which acupuncture regulates the HPA axis. These mechanisms include the modulation of multiple neurotransmitters and their receptors, neuropeptides and their receptors, and microRNAs in the paraventricular nucleus, hippocampus, amygdala and pituitary gland, which alleviate the hyperfunctioning of the HPA axis. This review comprehensively summarizes the mechanism of acupuncture in regulating HPA axis dysfunction for the first time, providing new targets and prospects for further exploration of acupuncture. Please cite this article as: Zheng JY, Zhu J, Wang Y, Tian ZZ. Effects of acupuncture on hypothalamic-pituitary-adrenal axis: Current status and future perspectives. J Integr Med. 2024; Epub ahead of print.

Electroacupuncture Ameliorates Hypothalamic‒Pituitary‒Adrenal Axis Dysfunction Induced by Surgical Trauma in Mice Through the Hypothalamic Oxytocin System

Electroacupuncture (EA) can effectively reduce surgical stress reactions and promote postoperative recovery, but the mechanisms remain unclear. The present study aims to examine the effects of EA on the hyperactivity of the hypothalamic‒pituitary‒adrenal (HPA) axis and investigate its potential mechanisms. Male C57BL/6 mice were subjected to partial hepatectomy (HT). The results showed that HT increased the concentrations of corticotrophin-releasing hormone (CRH), corticosterone (CORT), and adrenocorticotropic hormone (ACTH) in the peripheral blood and upregulated the expression of CRH and glucocorticoid receptors (GR) proteins in the hypothalamus. EA treatment significantly inhibited the hyperactivity of the HPA axis by decreasing the concentration of CRH, CORT, and ACTH in peripheral blood and downregulating the expression of CRH and GR in the hypothalamus. Moreover, EA treatment reversed the HT-induced downregulation of oxytocin (OXT) and oxytocin receptor (OXTR) in the hypothalamus. Furthermore, intracerebroventricular injection of the OXTR antagonist atosiban blocked the effects of EA. Thus, our findings implied that EA mitigated surgical stress-induced HPA axis dysfunction by activating the OXT/OXTR signaling pathway.

Electroacupuncture alleviates anxiety and modulates amygdala CRH/CRHR1 signaling in single prolonged stress mice

BACKGROUND

Post-traumatic stress disorder (PTSD) is an anxiety-related psychiatric disorder, manifesting high comorbidity with anxiety disorders. Its underlying neurobiological mechanisms have been associated with hypothalamic-pituitary-adrenal (HPA) axis dysfunction and stress hormones. Corticotropin-releasing hormone (CRH) is a primary stress hormone, expressed in the hypothalamus and amygdala. Electroacupuncture (EA) can improve mood disorders, but its mechanisms have not been fully elucidated. The aim of this study was to observe the effect of EA on PTSD and explore the related mechanisms.

METHODS

We used single prolonged stress (SPS) mice to establish a PTSD model, and EA was performed after SPS or 7 days later for a week. Then we observed their fear and anxiety-like behavior through cue-induced fear condition tests, open field test and the elevated zero maze. CRH and CRH receptor 1 (CRHR1) protein levels in the amygdala were measured in SPS mice after EA intervention.

RESULTS

We found that EA at ST36 and GV20 improved fear and anxiety behavior in SPS mice. The amygdala CRH and CRHR1 protein levels increased in the SPS mice, and this effect was reversed by the EA intervention. CRHR1 inhibition by the CRHR1 antagonist NBI 27914 alleviated anxiety behavior in SPS mice.

CONCLUSION

CRH/CRHR1 signaling in the amygdala may contribute to the anxiolytic effect of EA in SPS mice.

Antidepressant effect and neural mechanism of Acer tegmentosum in repeated stress-induced ovariectomized female rats

Acer tegmentosum (ATM) has antioxidant and anti-adipogenic activity. However, few studies have investigated the pharmacological activity or mechanism of ATM as an antidepressant agent. We assessed the antidepressant effect of ATM in modulating menopausal depressive symptoms and its mechanisms in ovariectomized (OVX) and repeatedly stressed (RS) female rats. The female rats were randomly divided into four groups: (1) naïve normal (normal) group, (2) OVX + repeated stress + saline-treated (control) group, (3) OVX + repeated stress + ATM (100 mg•kg⁻¹)-treated (ATM100) group and (4) OVX + repeated stress + ATM (400 mg•kg⁻¹)-treated (ATM400) group. We performed a battery of tests, such as the forced swimming test (FST), the sucrose intake test, and social exploration. After behavior testing, serum corticosterone levels were examined, followed by immunohistochemical determination of c-Fos, tyrosine hydroxylase (TH), and interleukin-1 beta (IL-1β) expression in the brain. ATM administration was associated with significantly decreased immobility time in the FST. Also, the control group tended to have decreased sucrose intake and social exploration compared with the normal group. However, ATM treatment was associated with markedly increased sucrose intake and active social exploration. In the paraventricular nucleus, c-Fos and IL-1β expression were significantly decreased in the ATM400 group compared with the control group. Compared with the control group, high-dose ATM administration was also associated with markedly decreased expression of TH-immunoreactive neurons in the locus coeruleus. The study findings demonstrated that ATM treatment effectively decreased behavioral and pathophysiological depression-like responses.

Electroacupuncture and Moxibustion Improved Anxiety Behavior in DSS-Induced Colitis Mice

Background and Aims

Psychological disorders are prevalent in patients with inflammatory bowel disease, but the underlying mechanisms remain unknown. The aim of this study was to study whether electroacupuncture (EA) and moxibustion (MB) can improve anxiety behavior in DSS-induced colitis mice and to investigate whether this effect is related to hypothalamic-pituitary-adrenocortical (HPA) axis.

Methods

The colitis model was established by drinking 2.5% dextran sodium sulfate (DSS). DSS-induced colitis mice were treated by EA or MB. Disease activity index (DAI) was scored; intestinal morphological and pathological structure was observed; anxiety behavior was tested by the elevated plus maze and open field. The concentration of corticotropin-releasing hormone (CRH) and cortisol (CORT) in serum was measured by enzyme-linked immunosorbent assay (ELISA). The protein expression of CRH in the colon and hypothalamus was detected by Western blot (WB).

Results

Both EA and MB treatments can improvethe morphology of their distal colonic mucosal epithelia, as well as the disease activity index. Meanwhile, anxiety behavior in colitis mice was improved slightly after EA and MB treatment. In addition, the levels of CRH and CORT in the serum were slightly improved after EA and MB treatment. These effects are further supported by WB results. The expression of CRH in the colon and hypothalamus was increased significantly after treatment, compared with the model group.

Conclusion

EA and MB were able to regulate the concentration of CRH in serum and protein expression in the peripheral and central at different levels and promote the recovery of the HPA axis that may be the basis for EA and MB to improve colonic pathology and alleviate anxiety behavior in DSS-induced colitis.

Isoflurane and the Analgesic Effect of Acupuncture and Electroacupuncture in an Animal Model of Neuropathic Pain

The present study aimed to determine whether isoflurane interferes with the analgesic effects of acupuncture (Ac) and electroacupuncture (EA), using a neuropathic pain (NP) rat model. In total, 140 male Wistar rats were used; isoflurane-induced nociceptive response was evaluated using the von Frey test, serum calcium-binding protein β (S100β) levels and nerve growth factor (NGF) levels in the left sciatic nerve. The NP model was induced by chronic constriction injury of the sciatic nerve at 14 days after surgery. Treatment was initiated after NP induction with or without isoflurane anesthesia (20 min/day/8 days). The von Frey test was performed at baseline, 14 days postoperatively, and immediately, 24 h, and 48 h after the last treatment. Results of the nociceptive test and three-way analysis of variance were analyzed by generalized estimating equations, the Bonferroni test, followed by Student-Newman-Keuls or Fisher's least significant difference tests for comparing biochemical parameters (significance defined as p ≤ 0.05). At baseline, no difference was noted in the nociceptive response threshold among all groups. Fourteen days after surgery, compared with other groups, NP groups showed a decreased pain threshold, confirming establishment of NP. Ac and EA enhanced the mechanical pain threshold immediately after the last session in the NP groups, without anesthesia. Isoflurane administration caused increased nociceptive threshold in all groups, and this effect persisted for 48 h after the last treatment. There was an interaction between the independent variables: pain, treatments, and anesthesia in serum S100β levels and NGF levels in the left sciatic nerve. Isoflurane enhanced the analgesic effects of Ac and EA and altered serum S100β and left sciatic nerve NGF levels in rats with NP.

The Modulatory Effect of Acupuncture on the Activity of Locus Coeruleus Neuronal Cells: A Review

The Locus Coeruleus (LC) is a small collection of noradrenergic neurons located in the pons. In the brain, noradrenaline (NE) is primarily produced by noradrenergic cell groups in the LC, which is the largest group of noradrenergic neurons in the central nervous system. Acupuncture, including the electroacupuncture which is a modified acupuncture method, is known to be effective in various kinds of diseases, and the involvement of noradrenergic system in the central nervous system has been reported by previous studies. However, on whether acupuncture can modulate the LC neuronal cells activities, results vary from studies to studies. In this paper, we included twelve articles, which observed the effect of acupuncture on the activities of LC in humans and animals. Our study shows that, among twelve included studies, six reported decrease of LC activities, whereas six showed increase of LC activities after acupuncture treatment. Although it is difficult to draw a firm conclusion, the authors suggest that the difference of frequencies may play an important role in the modulatory effect of acupuncture on LC. Further studies are needed to clarify the precise mechanism of acupuncture on LC, as it can lead to a new therapeutic method for various LC-NE related diseases.

Psychoneuroimmunoendocrinology: clinical implications

Psychoneuroimmunoendocrinology, which was first described in 1936, is the study of the interactions between the psyche, neural and endocrine functions and immune responses. The aim of psychoneuroimmunoendocrinology is to apply medical knowledge to the treatment of different allergic, immune, autoimmune, rheumatic, neoplastic, endocrine, cardiovascular and dental pathologies, among other disorders. Epigenetic factors and major stresses from different types of stimuli acting through distinct pathways and neurotransmitters are highly involved in altering the psychoneuroimmunoendocrine axis, resulting in the emergence of disease. The main purpose of this report is to expand the understanding of psychoneuroimmunoendocrinology and to demonstrate the importance of the above-mentioned interactions in the etiology of multiple pathologies. In this review, a search of the medical literature using PubMed (free access search engine for the Medline database of the National Library of Medicine of the United States) over the years 1936 to 2016 was conducted, and descriptive and experimental studies and reviews of the scientific literature were included.

Effects of electroacupuncture on stress and anxiety-related responses in rats

The aim of this work was to investigate if eletroacupuncture at PC6 would modulate the stress-induced anxiety-like behavior and the level of activation of several brain areas. Rats were distributed in groups: control; submitted to immobilization; submitted to immobilization and eletroacupuncture at PC6 or at the tail. Immobilization increased grooming and decreased stretched attend postures and the time spent in the open arms of the ele-vated plus-maze. Eletroacupuncture at PC6 or tail canceled the effect of immobilization on grooming and attenuated the stretched attend posture. Immobilization increased Fos-immunoreactivity in the prefrontal cortex, medial and central amygdala, paraventricular and dorsomedial nuclei of the hypothalamus, lateral hypothalamus, dentate gyrus, CA1, CA2 and CA3 hippocampal areas. The activation of paraventricular, dorsomedial nuclei and prefrontal cortex by immobilization was canceled by electroacupuncture at PC6 and attenuated by electroacupuncture in the tail. The activation of the other areas was canceled by electroacupuncture in PC6 or the tail. It is concluded that immobilization induced anxiety-like behavior that was moderately attenuated by eletroacupuncture with difference between the stimulation in PC6 or the rat tail. Eletroacupuncture showed specificity concerning to the attenuation of the effects of immobilization in the CNS areas related to the stress response, anxiety and cardiovascular system.

Inhibitory Effects and Mechanisms of Electroacupuncture via Chronically Implanted Electrodes on Stress-Induced Gastric Hypersensitivity in Rats With Neonatal Treatment of Iodoacetamide

BACKGROUND

Stress is considered an independent factor causing and aggravating gastrointestinal symptoms, including visceral pain. The aim of this study was to investigate effects and mechanisms of electroacupuncture (EA) on stress-induced gastric hypersensitivity in rats treated with neonatal iodoacetamide mimicking human functional dyspepsia (FD).

METHODS

Neonatal rats were treated with gavage of 0.2 mL of 0.1% iodoacetamide in 2% sucrose daily for six days starting on tenth day after birth. The control group was given 0.2 mL of 2% sucrose. When the rats were eight weeks old, acute restraint stress was performed on them for 90 min. EA at ST36 (ZuSanLi) was performed during the acute stress or 30 min after the stress. Adrenoceptor blocking drugs (propranolol and phentolamine) were injected intraperitoneally 30 min before acute restraint stress to explore possible sympathetic mechanisms. Visceral-motor responses to gastric distention were assessed by electromyogram (EMG).

RESULTS

1) Stress-induced gastric hypersensitivity was significantly more severe in the FD rats, compared to the control rats. It was blocked by the adrenoceptor antagonists. 2) EA inhibited stress-induced gastric hypersensitivity; the preventive effect of EA (given during stress) was more remarkable than the curative effect (given after stress). Stress resulted in a higher sympathovagal ratio and this was suppressed by EA.

CONCLUSIONS

Rats treated with neonatal iodoacetamide mimicking FD are more vulnerable to stress. Stress-induced gastric hypersensitivity can be prevented or suppressed by EA at ST36 via the restoration of sympathovagal balance.

Effects of acupuncture at Zu-San-Li (ST36) on the activity of the hypothalamic--pituitary--adrenal axis during ethanol withdrawal in rats

The current study investigated the effects of acupuncture at Zu-San-Li (ST36) on the hypothalamic-pituitary-adrenal axis during ethanol withdrawal in rats. Rats were intraperitoneally treated with 3 g/kg/day of ethanol or saline for 28 days. Following 24 hours of ethanol withdrawal, acupuncture was applied at bilateral ST36 points or non-acupoints (tail) for 1 minute. Plasma levels of corticosterone (CORT) and adrenocorticotropic hormone (ACTH) were measured by radioimmunoassay (RIA), and the corticotropin-releasing factor (CRF) protein levels in the paraventricular nucleus of the hypothalamus were also examined by RIA 20 minutes after the acupuncture treatment. RIA showed significantly increased plasma levels of CORT and ACTH in the ethanol-withdrawn rats compared with the saline-treated rats, which were inhibited significantly by the acupuncture at the acupoint ST36 but not at the non-acupoint. Additionally, ethanol withdrawal promoted CRF protein expressions in the paraventricular nucleus of the hypothalamus, which were also blocked by the acupuncture at ST36. These findings suggest that acupuncture at the specific acupoint ST36 can inhibit ethanol withdrawal-induced hyperactivation of hypothalamic-pituitary-adrenal axis, and it may be mediated via the modulation of hypothalamic CRF.

Acupuncture for functional dyspepsia: study protocol for a two-center, randomized controlled trial

Background

Functional dyspepsia (FD) is a common health problem currently without any optimal treatments. Acupuncture has been traditionally sought as a treatment for FD. The aim of this study is to investigate whether acupuncture treatment helps improve symptoms of FD.

Methods/design

A two-center, randomized, waitlist-controlled trial will be carried out to evaluate whether acupuncture treatment improves FD symptoms. Seventy six participants aged 18 to 75 years with FD as diagnosed by Rome III criteria will be recruited from August 2013 to January 2014 at two Korean Medicine hospitals. They will be randomly allocated either into eight sessions of partially individualized acupuncture treatment over 4 weeks or a waitlist group. The acupuncture group will then be followed-up for 3 weeks with six telephone visits and a final visit will be paid at 8 weeks. The waitlist group will receive the identical acupuncture treatment after a 4-week waiting period. The primary outcome is the proportion of responders with adequate symptom relief and the secondary outcomes include Nepean dyspepsia index, EQ-5D, FD-related quality of life, Beck’s depression inventory, state-trait anxiety inventory questionnaire, and level of ghrelin hormone. The protocol was approved by the participating centers’ Institutional Review Boards.

Discussion

Results of this trial will help clarify not only whether the acupuncture treatment is beneficial for symptom improvement in FD patients but also to elucidate the related mechanisms of how acupuncture might work.

Trial registration

ClinicalTrials.gov Identifier: NCT01921504.

Acupuncture and moxibustion for stress-related disorders

Acupuncture and moxibustion, which medical doctors are licensed by the government of Japan to perform, can improve the psychological relationship between doctors and patients, especially when it is disturbed by a “game”, a dysfunctional interpersonal interaction that is repeated unintentionally. This advantage is due to the essential properties of acupuncture and moxibustion. Acupuncture and moxibustion are helpful in treating somatoform disorders, especially musculoskeletal symptoms. In Japan, a holistic acupuncture and moxibustion therapy called Sawada-style has been developed. This is based on fundamental meridian points that are considered to have effects on central, autonomic nervous, immune, metabolic, and endocrine systems to regulate the whole body balance. In addition, some of the fundamental points have effects on Qi, blood, and water patterns associated with major depression, generalized anxiety disorder, eating disorders, and somatoform disorders. The fixed protocol of Sawada-style would be suitable for large-scale, randomized, controlled studies in the future. Recent systematic reviews indicate that electroacupuncture would be a useful addition to antidepressant therapy for some symptoms accompanying fibromyalgia. Acupuncture and moxibustion are also recommended for irritable bowel syndrome, instead of Western drug therapy. Surprisingly, the dorsal prefrontal cerebral cortex, which is associated with a method of scalp acupuncture applied for gastrointestinal disorders, has been found to be activated in patients with irritable bowel syndrome. It is quite possible that regulation of this cortical area is related to the effect of scalp acupuncture. This acupuncture method can be effective not only for irritable bowel syndrome but also for other stress-related gastrointestinal disorders.

CD4+CD25+ regulatory T cell depletion modulates anxiety and depression-like behaviors in mice

Stress has been shown to suppress immune function and increase susceptibility to inflammatory disease and psychiatric disease. CD4(+)CD25(+) regulatory T (Treg) cells are prominent in immune regulation. This study was conducted to determine if anti-CD25 antibody (Ab) mediated depletion of Treg cells in mice susceptibility to stress-induced development of depression-like behaviors, as well as immunological and neurochemical activity. To accomplish this, an elevated plus-maze test (EPM), tail suspension test (TST), and forced swim test (FST) were used to examine depression-like behaviors upon chronic immobilization stress. Immune imbalance status was observed based on analysis of serum cytokines using a mouse cytometric bead array in conjunction with flow cytometry and changes in the levels of serotonin (5-HT) and dopamine (DA) in the brain were measured by high performance liquid chromatography (HPLC). The time spent in the open arms of the EPM decreased significantly and the immobility time in the FST increased significantly in the anti-CD25 Ab-treated group when compared with the non stressed wild-type group. In addition, interlukin-6 (IL-6), tumor necrosis factor-á (TNF-á), interlukin-2 (IL-2), interferon-gamma (IFN-γ), interlukin-4 (IL-4) and interlukin-17A (IL-17A) concentrations were significantly upregulated in the stressed anti-CD25 Ab-treated group when compared with the non stressed wild-type group. Furthermore, the non stressed anti-CD25 Ab-treated group displayed decreased 5-HT levels within the hippocampus when compared with the non stressed wild-type group. These results suggest that CD4(+)CD25(+) Treg cell depletion modulated alterations in depressive behavior, cytokine and monoaminergic activity. Therefore, controlling CD4(+)CD25(+) Treg cell function during stress may be a potent therapeutic strategy for the treatment of depression-like symptoms.

Neural acupuncture unit: a new concept for interpreting effects and mechanisms of acupuncture

When an acupuncture needle is inserted into a designated point on the body and mechanical or electrical stimulation is delivered, various neural and neuroactive components are activated. The collection of the activated neural and neuroactive components distributed in the skin, muscle, and connective tissues surrounding the inserted needle is defined as a neural acupuncture unit (NAU). The traditionally defined acupoints represent an anatomical landmark system that indicates local sites where NAUs may contain relatively dense and concentrated neural and neuroactive components, upon which acupuncture stimulation would elicit a more efficient therapeutic response. The NAU-based local mechanisms of biochemical and biophysical reactions play an important role in acupuncture-induced analgesia. Different properties of NAUs are associated with different components of needling sensation. There exist several central pathways to convey NAU-induced acupuncture signals, Electroacupuncture (EA) frequency-specific neurochemical effects are related to different peripheral and central pathways transmitting afferent signals from different frequency of NAU stimulation. More widespread and intense neuroimaging responses of brain regions to acupuncture may be a consequence of more efficient NAU stimulation modes. The introduction of the conception of NAU provides a new theoretical approach to interpreting effects and mechanisms of acupuncture in modern biomedical knowledge framework.