Electroacupuncture pretreatment exhibits anti-depressive effects by regulating hippocampal proteomics in rats with chronic restraint stress

Acupuncture for brain diseases: Conception, application, and exploration

The brain is probably the most complex organ in the human body. It has been the hot spot and direction of brain science research all over the world to deeply study the pathogenesis of various kinds of brain diseases and find effective treatment methods. Acupuncture is a nonpharmacological therapy of traditional Chinese medicine originating from ancient clinical practice. The research on the treatment of brain diseases by acupuncture has been constantly enriched and updated with the promotion of interdisciplinary research. In order to account for the current achievements in the field of acupuncture for brain diseases, this article reviews it in terms of conception, application, and exploration. Based on the literature review, we found that in the past decades, acupuncture has received widespread attention worldwide and many literatures have reported the clinical efficacy and underlying mechanisms of acupuncture in the treatment of brain diseases. Presently, the conception, application, and exploration of acupuncture in the treatment of brain diseases have evolved from empirical medicine to evidence-based medicine and precision medicine, and are experiencing a deeper understanding of the information about acupuncture regulating the brain function based on interdisciplinary research.

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

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.

Factor analysis of electroacupuncture and selective serotonin reuptake inhibitors for major depressive disorder: an 8-week controlled clinical trial

BACKGROUND

There is evidence supporting electroacupuncture (EA) for the treatment of major depressive disorder (MDD), but its characteristics have not been well investigated.

OBJECTIVE

To investigate the effectiveness and characteristics of EA in MDD.

METHODS

60 subjects were enrolled-35 in the EA group and 25 in the selective serotonin reuptake inhibitor (SSRI) group based on their preferences-in an 8-week non-randomised controlled clinical trial. The 24-item Hamilton depression rating scale (HAMD-24) and clinical global impression (CGI) were adopted for clinical assessment. The Columbia suicide severity rating scale and adverse event form were used to measure safety and tolerability. The characteristics of EA and SSRIs were compared by analysing seven factors of the HAMD-24.

RESULTS

There was no significant difference between the two groups in terms of HAMD-24 response rate after intervention (P>0.05). Patients treated with EA demonstrated a significant reduction in CGI scores (P<0.05) with fewer adverse events compared with SSRIs (P<0.01). Although HAMD-24 factor analysis showed both EA and SSRIs could improve factor scores in cognitive impairment, diurnal variation, retardation, sleep disturbance, anxiety/somatisation and feelings of despair, EA showed greater improvement in anxiety/somatisation and feelings of despair than SSRIs (P<0.05).

CONCLUSIONS

There was no significant difference between EA and SSRIs in the treatment of MDD with respect to our primary outcome. However, as a potential therapy for MDD, EA appeared to result in greater symptom improvement than SSRI treatment with respect to anxiety/somatisation and feelings of despair. The results of this secondary analysis should be interpreted cautiously given the inherent issues of multiple testing.

The Role of MAPK and Dopaminergic Synapse Signaling Pathways in Antidepressant Effect of Electroacupuncture Pretreatment in Chronic Restraint Stress Rats

Acupuncture has demonstrated the function in ameliorating depressive-like behaviors via modulating PKA/CREB signaling pathway. To further confirm the antidepressant mechanism of EA on the mitogen-activated protein kinase (MAPK) and dopaminergic synapse signaling pathways, 4 target proteins were detected based on our previous iTRAQ analysis. Rats were randomly divided into control group, model group, and electroacupuncture (EA) group. Except for the control group, all rats were subjected to 28 days of chronic restraint stress (CRS) protocols to induce depression. In the EA group, EA pretreatment at Baihui (GV20) and Yintang (GV29) was performed daily (1 mA, 2 Hz, discontinuous wave, 20 minutes) prior to restraint. The antidepressant-like effect of EA was measured by body weight and open-field test. The protein levels of DAT, Th, Mapt, and Prkc in the hippocampus were examined by using Western blot. The results showed EA could ameliorate the depression-like behaviors and regulate the expression levels of Prkc and Mapt in CRS rats. The effect of EA on DAT and Th expression was minimal. These findings implied that EA pretreatment could alleviate depression through modulating MAPK signaling pathway. The role of EA on dopaminergic synapse signaling pathways needs to be further explored.

Antidepressant Mechanism Research of Acupuncture: Insights from a Genome-Wide Transcriptome Analysis of Frontal Cortex in Rats with Chronic Restraint Stress

Major depressive disorder (MDD) is a chronic disease that adversely affects mood and cognition. In this study, we randomly divided the rats into control group (C), model group (M), fluoxetine group (F), and acupuncture group (A), used open-field test to ascertain whether acupuncture affects chronic restraint stress (CRS) induced depression-like behaviors of rats, and explored the antidepressant mechanism of acupuncture at the molecular level of transcriptome in the frontal cortex of CRS rats by RNA-sequencing (RNA-seq). According to differentially expressed genes (DEG) analysis, we identified 134, 46, and 89 response genes differentially expressed in C versus M, F versus M, and A versus M, respectively. Through Gene Ontology (GO) term enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, we identified the gene sets involved in extracellular space, inflammatory response, Toll-like receptor signaling pathway, chemokine signaling pathway, and TNF signaling pathway. In this study, RNA-seq technology was used to investigate the frontal cortex genome-wide transcriptomes in depression rats under CRS, which suggested that the antidepressant effect of acupuncture is effective and has a multitarget characteristic, which may be related to amino acid metabolism and inflammatory pathways, especially the Toll-like receptor signaling pathway, TNF signaling pathway, and NF-kappa B signaling pathway.

Genome-wide transcriptome analysis of hippocampus in rats indicated that TLR/NLR signaling pathway was involved in the pathogenisis of depressive disorder induced by chronic restraint stress

Data from clinical investigations and laboratory fundings have provided preliminary evidence for the effectiveness and safety of acupuncture therapy in depression. However, the mechanisms underlying the antidepressant response of acupuncture are not fully elucidated. To elucidate the potential effects of acupuncture for depression on the hippocampal genome-wide transcriptome at the molecular level, we evaluated the transcriptomic profile of depression rats under treatment of acupuncture, and fluoxetine. We identified a very significant effect of acupucture intervention, with 107 genes differentially expressed in acupuncture vs. model group; while 41 genes between fluoxetine vs. model group. Notably, the 54 differentially expressed genes between acupuncture and fluoxetine showed the significantly different effect between acupuncture and fluoxetine. Through GO (gene ontology) functional term and KEGG (kyoto encyclopedia of genes and genomes) pathway analysis, we identified that the upregulation of gene sets were related to inflammatory response, innate immunity and immune response. We found that toll-like receptor signalling pathway and NOD like receptor signalling pathway were associated with the function of inflammatory response, innate immunity and immune response. Importantly, acupuncture reversed the upregulation of gene sets that were related to inflammatory response, innate immunity and immune response (including toll-like receptor signalling pathway and NOD like receptor signalling pathway), which might be critical for the pathogenesis of depression and provide evidence for the antidepressive effects of acupuncture by regulating inflammatory response, innate immunity and immune response via toll-like receptor signalling pathway and NOD like receptor signalling pathway.

Mechanisms Underlying the Antidepressant Response of Acupuncture via PKA/CREB Signaling Pathway

Protein kinase A (PKA)/cAMP response element-binding (CREB) protein signaling pathway, contributing to impaired neurogenesis parallel to depressive-like behaviors, has been identified as the crucial factor involved in the antidepressant response of acupuncture. However, the molecular mechanisms associated with antidepressant response of acupuncture, neurogenesis, and depressive-like behaviors ameliorating remain unexplored. The objective was to identify the mechanisms underlying the antidepressant response of acupuncture through PKA signaling pathway in depression rats by employing the PKA signaling pathway inhibitor H89 in in vivo experiments. Our results indicated that the expression of hippocampal PKA-α and p-CREB was significantly downregulated by chronic unpredicted mild stress (CUMS) procedures. Importantly, acupuncture reversed the downregulation of PKA-α and p-CREB. The expression of PKA-α was upregulated by fluoxetine, but not p-CREB. No significant difference was found between Acu and FLX groups on the expression of PKA-α and p-CREB. Interestingly, H89 inhibited the effects of acupuncture or fluoxetine on upregulating the expression of p-CREB, but not PKA-α. There was no significant difference in expression of CREB among the groups. Conclusively, our findings further support the hypothesis that acupuncture could ameliorate depressive-like behaviors by regulating PKA/CREB signaling pathway, which might be mainly mediated by regulating the phosphorylation level of CREB.

Electroacupuncture pretreatment with different waveforms prevents brain injury in rats subjected to cecal ligation and puncture via inhibiting microglial activation, and attenuating inflammation, oxidative stress and apoptosis

Sepsis is associated with high morbidity and mortality. This study was to investigate the protective effects of electroacupuncture (EA) pretreatment with different waveforms on septic brain injury in rats and its mechanism. Male Sprague-Dawley rats were pretreated by EA with different waveforms (continuous wave, dilatational wave, or intermittent wave) at Baihui (GV20) and Tsusanli (ST36) acupoints for 30min, and underwent cecal ligation and puncture (CLP) or sham operation. The results showed that EA pretreatment with different waveforms improved survival rate, attenuated encephaledema, brain injury, neuronal apoptosis and cognitive dysfunction, and preserved blood-brain barrier (BBB). EA pretreatment decreased the production of tumor necrosis factor(TNF)-α, interleukin(IL)-6, malondialdehyde (MDA), and increased the activity of superoxide dismutase (SOD) and catalase (CAT) in serum and hippocampus at 48h after sham or CLP operation. Additionally, EA pretreatment downregulated the expressions of toll-like receptor-4 (TLR-4), nuclear factor-kappa B (NF-κB) and ionized calcium binding adaptor molecule 1(Iba 1). The effect of dilatational wave was the most significant, followed by intermittent wave, and continuous wave was relatively poor. In conclusion, our results demonstrate that EA pretreatment with three waveforms alleviates sepsis-induced brain injury by inhibition of microglial activation and attenuation of inflammation, oxidative stress and apoptosis. These findings suggest that EA pretreatment with dilatational wave at Baihui and Tsusanli acupoints might be a promising therapeutic strategy for relieving septic brain injury.

Antidepressant effect of electroacupuncture regulates signal targeting in the brain and increases brain-derived neurotrophic factor levels

Electroacupuncture improves depressive behavior faster and with fewer adverse effects than antidepressant medication. However, the antidepressant mechanism of electroacupuncture remains poorly understood. Here, we established a rat model of chronic unpredicted mild stress, and then treated these rats with electroacupuncture at Yintang (EX-HN3) and Baihui (DU20) with sparse waves at 2 Hz and 0.6 mA for 30 minutes, once a day. We found increased horizontal and vertical activity, and decreased immobility time, at 2 and 4 weeks after treatment. Moreover, levels of neurotransmitters (5-hydroxytryptamine, glutamate, and γ-aminobutyric acid) and protein levels of brain-derived neurotrophic factor and brain-derived neurotrophic factor-related proteins (TrkB, protein kinase A, and phosphorylation of cyclic adenosine monophosphate response element binding protein) were increased in the hippocampus. Similarly, protein kinase A and TrkB mRNA levels were increased, and calcium-calmodulin-dependent protein kinase II levels decreased. These findings suggest that electroacupuncture increases phosphorylation of cyclic adenosine monophosphate response element binding protein and brain-derived neurotrophic factor levels by regulating multiple targets in the cyclic adenosine monophosphate response element binding protein signaling pathway, thereby promoting nerve regeneration, and exerting an antidepressive effect.