The mechanism of electroacupuncture for depression on basic research: a systematic review

Abstract

Background Electroacupuncture (EA) is generally accepted as a safe and harmless treatment option for alleviating depression. However, there are several challenges related to the use of EA. Although EA has been shown to be effective in treating depression, the molecular mechanism is unclear. Objective To reveal the therapeutic effect of EA and its possible mechanism in the treatment of depression. Search strategy We performed a systematic search according to PRISMA guidelines. We electronically searched PubMed, Web of Science (WOS), the China National Knowledge Infrastructure (CNKI), Wanfang Data Information Site and the VIP information database for animal studies in English published from the inception of these databases to December 31, 2019. Inclusion criteria Electronic searches of PubMed, WOS, the CNKI, Wanfang and the VIP database were conducted using the following search terms: (depression OR depressive disorder OR antidepressive), (rat OR mouse) AND (acupuncture OR EA). Data extraction and analysis The data were extracted primarily by one author, and a follow-up review was conducted by the other authors. Results Twenty-eight articles met the inclusion criteria. The most commonly used method for inducing depression in animal models was 21 days of chronic unpredictable mild stress. For the depression model, the most commonly selected EA frequency was 2 Hz. Among the 28 selected studies, 11 studies observed depression-related behaviors and used them as indicators of EA efficacy. The other 17 studies focused on mechanisms and assessed the indexes that exhibited abnormalities that were known to result from depression and then returned to a normal range after EA treatment. Treatment of depression by EA involves multiple therapeutic mechanisms, including inhibition of HPA axis hyperactivity and inflammation, regulation of neuropeptides and neurotransmitters, modulation of the expression of particular genes, restoration of hippocampal synaptic plasticity, increased expression of BDNF, and regulation of several signaling pathways. Conclusions This review reveals that the mechanisms underlying the effect of acupuncture involve multiple pathways and targets, suggesting that acupuncture is a wholistic treatment for people rather than for diseases. Our findings also explain why acupuncture can treat various disorders in addition to depression.

Effect of Electroacupuncture on Bladder Dysfunction via Regulation of MLC and MLCK Phosphorylation in a Rat Model of Type 2 Diabetes Mellitus

“…EA has been widely accepted as an alternative therapy for various diseases [ 42 ]. The efferent signal from the spinal micturition center is sent to the intramural ganglion of the bladder wall along with the pelvic nerve, which can cause contraction of the bladder detrusor smooth muscle [ 43 , 44 ].…”

Acupuncture: A Promising Approach for Comorbid Depression and Insomnia in Perimenopause

“…122 A previous SR suggested that EA could reduce cortisol (CORT) release from the adrenal glands and thereby modify the HPA axis by downregulating the expression of corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) in the hypothalamus and pituitary gland, respectively, as well as decreasing the expression of CRH mRNA in the hypothalamus. 123 This hypothesis was tested in a PMD model by Jiang et al 124 In this study, EA showed antidepressant-like effects that were no weaker than clomipramine in PMD rats, along with significant reductions in CRH, ACTH and CORT. Jiang also reported an increase in E2 and a decrease in FSH and LH levels in the rats.…”

“…In addition to the enhancement of 5-HT synthesis and the increase of 5-HT and its metabolite content in the brain and synaptic gaps, previous studies also suggested that acupuncture restored synaptic plasticity by regulating serotonin expression in the hippocampus resulting in relieved depression symptoms. 123,150 This process involves acupuncture-induced bidirectional regulation of the expression of serotonin transporters (5-HTTs) and serotonin-1A (5-HT1A), which then increases the expression of hippocampal galanin (Gal) and tryptophan hydroxylase (TPH) as well as restores or reverses the impairments in synaptic plasticity. 123 Given existing animal studies mainly focused on hippocampus, future studies within in field might benefit from some investigations of other cerebral regions important for depressive-like symptoms including amygdala and prefrontal cortex.…”

“…123,150 This process involves acupuncture-induced bidirectional regulation of the expression of serotonin transporters (5-HTTs) and serotonin-1A (5-HT1A), which then increases the expression of hippocampal galanin (Gal) and tryptophan hydroxylase (TPH) as well as restores or reverses the impairments in synaptic plasticity. 123 Given existing animal studies mainly focused on hippocampus, future studies within in field might benefit from some investigations of other cerebral regions important for depressive-like symptoms including amygdala and prefrontal cortex. Serotonin also plays an integral part in the process of sleep preparation, initiation, and maintenance.…”

“…The effects of acupuncture on signaling pathways have also been widely studied, providing a new perspective to understand the clinical efficacy of acupuncture at a molecular level. 123 We identified six animal studies involving three signal transduction pathways that revealed possible mechanisms implicated in the improvement of PMD by acupuncture.…”