Effects of electroacupuncture on the cortical extracellular signal regulated kinase pathway in rats with cerebral ischaemia/reperfusion

Optimized Separation of Carthamin from Safflower by Macroporous Adsorption Resins and Its Protective Effects on PC12 Cells Injured by OGD/R via Nrf2 Signaling Pathway

The growing demand for safe natural products has reignited people's interest in natural food pigments. Here, we proposed the use of macroporous adsorption resins (MARs) to separate and purify carthamin from safflower. The optimal parameters for carthamin purification with HPD400 MAR were determined as follows: a mass ratio of crude carthamin in sample solution to wet resin of 0.3, a crude carthamin solution concentration of 0.125 g·mL-1, a pH of 6.00, a sample volume flow rate of 0.5 mL·min-1, an ethanol volume fraction of 58%, an elution volume of 4 BV, and an elution volume flow rate of 1.0 mL·min-1. Under the above purification conditions, the recovery rate of carthamin was above 96%. Carthamin dramatically improved the survival rate of PC12 cells damaged by oxygen-glucose deprivation/reoxygenation and protected them from oxidative stress by inhibiting the generation of reactive oxygen species and increasing the total antioxidant capacity and glutathione (GSH) levels. Carthamin promoted extracellularly regulated protein kinase phosphorylation into the nucleus, permitting Nrf2 nuclear translocation and upregulating the gene expression of the rate-limiting enzymes glutamate-cysteine ligase catalytic subunit and glutamate-cysteine ligase regulatory subunit of GSH synthesis to obliterate free radicals and exert antioxidant effects. This study revealed the purification method of carthamin and its antioxidant protective effects, providing important insights into the application of carthamin in functional foods.

Lignans as multi-targeted natural products in neurodegenerative diseases and depression: Recent perspectives

As the global population ages, the treatment of neurodegenerative diseases is becoming more and more important. There is an urgent need to discover novel drugs that are effective in treating neurological diseases. In recent years, natural products and their biological activities have gained widespread attention. Lignans are a class of metabolites extensively present in Chinese herbal medicine and possess good pharmacological effects. Latest studies have demonstrated their neuroprotective pharmacological activity in preventing acute/chronic neurodegenerative diseases and depression. In this review, the pharmacological effects of these disorders, the pharmacokinetics, safety, and clinical trials of lignans were summarized according to the scientific literature. These results proved that lignans mainly exert antioxidant and anti-inflammatory activities. Anti-apoptosis, regulation of nervous system functions, and modulation of synaptic signals are also potential effects. Despite the substantial evidence of the neuroprotective potential of lignans, it is not sufficient to support their use in the clinical management. Our study suggests that lignans can be used as prospective agents for the treatment of neurodegenerative diseases and depression, with a view to informing their further development and utilization.

Mechanism of Electroacupuncture Against Cerebral Ischemia–Reperfusion Injury: Reducing Inflammatory Response and Cell Pyroptosis by Inhibiting NLRP3 and Caspase-1

Cell pyroptosis is one of the main forms of neuronal injury after cerebral ischemia–reperfusion. It is accompanied by an inflammatory reaction and regulated by the caspase gene family. Electroacupuncture (EA) can reduce neuronal injury caused by cerebral ischemia–reperfusion, and we speculated that EA can prevent neuronal pyroptosis after cerebral ischemia–reperfusion by regulating the nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3)/caspase-1 pathway. The cerebral ischemia–reperfusion injury model of C57 and caspase-1 gene knockout (Cas-1 ko) mice was established by Longa's method. EA was conducted at acupoints Chize (LU5), Hegu (LI4), Sanyinjiao (SP6), and Zusanli (ST36) for 1.5 h after cerebral ischemia–reperfusion injury for 20 min, and observation was carried out after 24 h. Neurological deficit scores evaluated the neurological function, cerebral infarction volume was observed by triphenyl tetrazolium chloride (TTC) staining, hematoxylin and eosin (H&E) staining, TUNEL and caspase-1 double-labeled fluorescence staining, and NLRP3 and caspase-1 double-labeled immunofluorescence staining that were used to observe the morphology of neurons in hippocampus, and the protein expression of NLRP3, pro-caspase-1, cleaved caspase-1 p20, pro-interleukin-1β (IL-1β), cleaved IL-1β, and GSDMD was detected by Western blot assay. Results showed that EA could reduce the score of neurological deficit, reduce the volume of cerebral infarction and improve the degree of nerve cell injury, and inhibit NLRP3, pro-caspase-1, cleaved caspase-1 p20, pro-IL-1β, cleaved IL-1β, and GSDMD protein expression. In summary, EA plays a neuroprotective role by reducing the pyroptotic neurons that were caspase 1-mediated and inflammatory response after cerebral ischemia–reperfusion.

Visualization and Analysis of the Mapping Knowledge Domain of Acupuncture and Central Nervous System Cell Apoptosis

Chinese acupuncture therapy has demonstrated good clinical effects on neurological diseases and is widely used internationally. In the past 20 years, an increasing number of researchers around the world have devoted themselves to the study of the effect and mechanism of acupuncture for the treatment of central nervous system cell apoptosis. To discover the current research status of acupuncture-induced antiapoptosis in the central nervous system, we used the method of scientometric research and data visualization software to visually analyse 155 articles. The findings are as follows. First, the antiapoptosis effects of acupuncture in the central nervous system have received increasing attention overseas and domestically. China and the United States have leading positions in this research field. Second, 5 stable and high-yielding research teams have been formed in the field of acupuncture-induced antiapoptosis. The main research directions of these teams are electroacupuncture (EA) pretreatment for the central nervous system cell apoptosis, acupuncture for antineuronal apoptosis in vascular dementia, EA regulation of related signalling pathways, EA regulation of nerve cell apoptosis and autophagy after stroke, and EA regulation of the MAPK signalling pathway. Researchers on teams with more extensive cooperation have more research results and better research continuity. Third, there are diversified research hotspots. The original research hotspots are still receiving attention, and new hotspots have emerged in recent years.

Integrated Bioinformatics Analysis of Potential mRNA and miRNA Regulatory Networks in Mice With Ischemic Stroke Treated by Electroacupuncture

Background: The complicated molecular mechanisms underlying the therapeutic effect of electroacupuncture (EA) on ischemic stroke are still unclear. Recently, more evidence has revealed the essential role of the microRNA (miRNA)–mRNA networks in ischemic stroke. However, a systematic analysis of novel key genes, miRNAs, and miRNA–mRNA networks regulated by EA in ischemic stroke is still absent.

Methods: We established a middle cerebral artery occlusion (MCAO) mouse model and performed EA therapy on ischemic stroke mice. Behavior tests and measurement of infarction area were applied to measure the effect of EA treatment. Then, we performed RNA sequencing to analyze differentially expressed genes (DEGs) and functional enrichment between the EA and control groups. In addition, a protein–protein interaction (PPI) network was built, and hub genes were screened by Cytoscape. Upstream miRNAs were predicted by miRTarBase. Then hub genes and predicted miRNAs were verified as key biomarkers by RT-qPCR. Finally, miRNA–mRNA networks were constructed to explore the potential mechanisms of EA in ischemic stroke.

Results: Our analysis revealed that EA treatment could significantly alleviate neurological deficits in the affected limbs and reduce infarct area of the MCAO model mice. A total of 174 significant DEGs, including 53 upregulated genes and 121 downregulated genes, were identified between the EA and control groups. Functional enrichment analysis showed that these DEGs were associated with the FOXO signaling pathway, NF-kappa B signaling pathway, T-cell receptor signaling pathway, and other vital pathways. The top 10 genes with the highest degree scores were identified as hub genes based on the degree method, but only seven genes were verified as key genes according to RT-qPCR. Twelve upstream miRNAs were predicted to target the seven key genes. However, only four miRNAs were significantly upregulated and indicated favorable effects of EA treatment. Finally, comprehensive analysis of the results identified the miR-425-5p-Cdk1, mmu-miR-1186b-Prc1, mmu-miR-434-3p-Prc1, and mmu-miR-453-Prc1 miRNA–mRNA networks as key networks that are regulated by EA and linked to ischemic stroke. These networks might mainly take place in neuronal cells regulated by EA in ischemic stroke.

Conclusion: In summary, our study identified key DEGs, miRNAs, and miRNA–mRNA regulatory networks that may help to facilitate the understanding of the molecular mechanism underlying the effect of EA treatment on ischemic stroke.

Effect of Acupuncture on the p38 Signaling Pathway in Several Nervous System Diseases: A Systematic Review

Acupuncture is clinically used to treat various diseases and exerts positive local and systemic effects in several nervous system diseases. Advanced molecular and clinical studies have continually attempted to decipher the mechanisms underlying these effects of acupuncture. While a growing understanding of the pathophysiology underlying several nervous system diseases shows it to be related to inflammation and impair cell regeneration after ischemic events, the relationship between the therapeutic mechanism of acupuncture and the p38 MAPK signal pathway has yet to be elucidated. This review discusses the latest advancements in the identification of the effect of acupuncture on the p38 signaling pathway in several nervous system diseases. We electronically searched databases including PubMed, Embase, and the Cochrane Library from their inception to April 2020, using the following keywords alone or in various combinations: "acupuncture", "p38 MAPK pathway", "signaling", "stress response", "inflammation", "immune", "pain", "analgesic", "cerebral ischemic injury", "epilepsy", "Alzheimer's disease", "Parkinson's disease", "dementia", "degenerative", and "homeostasis". Manual acupuncture and electroacupuncture confer positive therapeutic effects by regulating proinflammatory cytokines, ion channels, scaffold proteins, and transcription factors including TRPV1/4, Nav, BDNF, and NADMR1; consequently, p38 regulates various phenomena including cell communication, remodeling, regeneration, and gene expression. In this review article, we found the most common acupoints for the relief of nervous system disorders including GV20, GV14, ST36, ST37, and LI4. Acupuncture exhibits dual regulatory functions of activating or inhibiting different p38 MAPK pathways, contributing to an overall improvement of clinical symptoms and function in several nervous system diseases.

Electroacupuncture reduces fibromyalgia pain by downregulating the TRPV1-pERK signalling pathway in the mouse brain

BACKGROUND

Acupuncture has been clinically recommended as a method of pain relief by the World Health Organization and is widely used by medical doctors. Fibromyalgia (FM) pain has a complex physiological and psychological origin and can be pharmacologically treated with duloxetine, milnacipran and pregabalin. However, these drugs produce undesirable side effects, such as headaches, nausea and diarrhoea. Acupuncture may serve as an effective alternative treatment for pain relief with few side effects.

AIMS

We hypothesised that acupuncture would reduce FM pain by influencing transient receptor potential cation channel subfamily V member 1 (TRPV1) and the downstream phosphorylated extracellular signal-regulated kinases (pERK), which are located in the central thalamus, amygdala and cortex.

METHODS

A FM mouse model was established by injecting two doses of acid saline into 32 female C57/B6 mice. The mice were then assigned to different subgroups (n=8 each) and treated with electroacupuncture (EA) or EA sham control. TRPV1 and pERK expression levels were measured using Western blotting and immunohistochemistry.

RESULTS

Our results demonstrated that the expression of TRPV1 and pERK in the thalamus, amygdala and somatosensory cortex was normal in the control mice, but significantly increased in FM mice; these FM-induced changes in expression were attenuated by EA.

CONCLUSION

Our data suggest that EA can reverse the central sensitisation of the TRPV1-ERK signalling pathway in the mouse brain. Thus, our findings provide mechanistic evidence supporting the potential therapeutic efficacy of EA for treating FM pain.

Signal Transduction Pathways of Acupuncture for Treating Some Nervous System Diseases

In this article, we review signal transduction pathways through which acupuncture treats nervous system diseases. We electronically searched the databases, including PubMed, MEDLINE, clinical Key, the Cochrane Library, and the China National Knowledge Infrastructure from their inception to December 2018 using the following MeSH headings and keywords alone or in varied combination: acupuncture, molecular, signal transduction, genetic, cerebral ischemic injury, cerebral hemorrhagic injury, stroke, epilepsy, seizure, depression, Alzheimer's disease, dementia, vascular dementia, and Parkinson's disease. Acupuncture treats nervous system diseases by increasing the brain-derived neurotrophic factor level and involves multiple signal pathways, including p38 MAPKs, Raf/MAPK/ERK 1/2, TLR4/ERK, PI3K/AKT, AC/cAMP/PKA, ASK1-JNK/p38, and downstream CREB, JNK, m-TOR, NF-κB, and Bcl-2/Bax balance. Acupuncture affects synaptic plasticity, causes an increase in neurotrophic factors, and results in neuroprotection, cell proliferation, antiapoptosis, antioxidant activity, anti-inflammation, and maintenance of the blood-brain barrier.

Acupuncture attenuates cognitive impairment, oxidative stress and NF-κB activation in cerebral multi-infarct rats

BACKGROUD

Patients with multiple infarct dementia (MID) have subtle deficits that commonly go unnoticed, and are at risk of developing Alzheimer's disease. Oxidative stress induced by ischaemic injury results in intracellular calcium accumulation and neuronal apoptosis, leading to cognitive impairment by triggering various cellular signal transduction pathways. Several studies have suggested that NF-κB in the presence of p53 has a pro-apoptotic function in various models, but the mechanism is unclear.

AIMS

The aim of this study was to investigate whether acupuncture could protect cognitive function against cerebral multi-infarction (CMi) induced oxidative stress by inhibiting the activation of NF-κB and its target gene p53.

METHODS

An animal model of CMi was established by injecting homologous blood emboli into the right internal carotid artery of male Wistar rats. After 2 weeks of acupuncture treatment, cognitive function was detected by novel object recognition. Electron spin resonance and Fluo-3 fuorescence imaging were used to test the generation of ROS and intracellular calcium accumulation, respectively. Expression of NF-κB and p53 was examined by Western blot analysis and immunofluorescence.

RESULTS

CMi induced spatial learning and memory impairment, overproduction of intracellular hydroxyl radicals, and elevations of Ca²⁺, which were ameliorated by verum acupuncture treatment. Acupuncture inhibited activation of NF-κB and its downstream target gene p53.

CONCLUSION

These findings suggest that acupuncture could protect cognitive function against oxidative stress induced by CMi, which is partially associated with suppression of NF-κB-p53 activation.

Electroacupuncture Alleviated Neuronal Apoptosis Following Ischemic Stroke in Rats via Midkine and ERK/JNK/p38 Signaling Pathway

This study aimed to evaluate the effects of electroacupuncture (EA) intervention administered at rats of middle cerebral artery occlusion (MCAO)/reperfusion. Fifty-four male Sprague-Dawley rats were divided into three groups, consisting of sham group, MCAO/R group, and EA group. EA treatment at Quchi and Zusanli acupoints was applied in rats of EA group at 24 h after MCAO once per day for 3 days. Our results indicated that EA treatment reduced infarct volumes and neurological deficits, as well alleviated the apoptotic cells in peri-infarct cortex, indicating that EA exerted neuroprotective effect in cerebral ischemic rats. Moreover, EA treatment may effectively reverse the upregulation of caspase-3 and Bim and alleviate the inhibition of Bcl-2 following 72-h ischemic stroke. EA may significantly reverse the promoted relative density level of p-ERK1/2, p-JNK, and p-p38 in the EA group compared with the MCAO/R group. In addition, the growth factor midkine (MK) was upregulated at 72 h after MCAO/R, and EA treatment may significantly prompt expression of MK. Our study demonstrated that EA exerted neuroprotective effect against neuronal apoptosis and the mechanism might involve in upregulation of MK and mediation of ERK/JNK/p38 signal pathway.

Electroacupuncture: a new approach to open the blood-brain barrier in rats recovering from middle cerebral artery occlusion

Objective

To examine for an opening effect on the blood–brain barrier (BBB) in intact rats and rats with experimental ischaemia-reperfusion (I/R) during the recovery period after various electroacupuncture (EA) treatments with different time courses, and to determine whether there is a time-dependent effect. An additional objective was to determine whether this method could induce the penetration of nerve growth factor (NGF) through the BBB.

Methods

A middle cerebral artery occlusion (MCAO) model was first established. We chose different stimulation time courses and observed the effects of EA treatment (100 Hz frequency; 2 mA intensity) at GV20 and GV26 on the BBB in rats recovering from MCAO 3 weeks after modelling. The rats were injected with 2% Evans blue (EB) saline. The brain water content was measured using a wet/dry weighing method. The degree of penetration of EB was detected using spectrophotometry and laser confocal microscopy. The rats were then injected with NGF, and the concentration of NGF in the brain tissues was measured using ELISA.

Results

The increase in the BBB permeability was most notable following the 8 min EA stimulation (P<0.05), which may be advantageous for the targeted delivery of drugs (such as NGF) into the brain. Additionally, this effect did not appear to cause brain oedema (P>0.05) in healthy or MCAO rats.

Conclusions

EA treatment for a certain stimulation time at GV20 and GV26 in MCAO rats can increase BBB permeability.