Electroacupuncture pretreatment prevents cognitive impairment induced by limb ischemia–reperfusion via inhibition of microglial activation and attenuation of oxidative stress in rats

Communication Regarding the Myocardial Ischemia/Reperfusion and Cognitive Impairment: A Narrative Literature Review

Coronary artery disease is a prevalent ischemic disease that results in insufficient blood supply to the heart muscle due to narrowing or occlusion of the coronary arteries. Various reperfusion strategies, including pharmacological thrombolysis and percutaneous coronary intervention, have been developed to enhance blood flow restoration. However, these interventions can lead to myocardial ischemia/reperfusion injury (MI/RI), which can cause unpredictable complications. Recent research has highlighted a compelling association between MI/RI and cognitive function, revealing pathophysiological mechanisms that may explain altered brain cognition. Manifestations in the brain following MI/RI exhibit pathological features resembling those observed in Alzheimer's disease (AD), implying a potential link between MI/RI and the development of AD. The pro-inflammatory state following MI/RI may induce neuroinflammation via systemic inflammation, while impaired cardiac function can result in cerebral under-perfusion. This review delves into the role of extracellular vesicles in transporting deleterious substances from the heart to the brain during conditions of MI/RI, potentially contributing to impaired cognition. Addressing the cognitive consequence of MI/RI, the review also emphasizes potential neuroprotective interventions and pharmacological treatments within the MI/RI model. In conclusion, the review underscores the significant impact of MI/RI on cognitive function, summarizes potential mechanisms of cardio-cerebral communication in the context of MI/RI, and offers ideas and insights for the prevention and treatment of cognitive dysfunction following MI/RI.

Electroacupuncture ameliorates chronic unpredictable mild stress-induced depression-like behavior and cognitive impairment through suppressing oxidative stress and neuroinflammation in rats

BACKGROUND

Depression is associated with lowered mood, anxiety, anhedonia, cognitive impairments, and even suicidal tendencies in severe cases. Yet few studies have directed acupuncture's mechanism toward enhancing axonal repair correlated with synaptic plasticity and anti-inflammatory effects related to oxidative stress in the hippocampus.

METHODS

Male Sprague-Dawley (SD) rats were randomly divided into control group (CON), chronic unpredictable mild stress (CUMS) group, CUMS + electroacupuncture group (EA), and CUMS + fluoxetine group (FLX) (n = 10/group). Rats were given a 28-day treatment at the Shangxing (GV23) and Fengfu (GV16) acupoints with electroacupuncture or fluoxetine (2.1 mg/kg).

RESULTS

Rats exposed to CUMS induced depression-like behaviors and spatial learning-memory impairment, changed the ionized calcium binding adaptor molecule 1 (IBA-1), Vglut1, myelin basic protein (MBP), and postsynaptic density protein 95 (PSD95) level of hippocampal, increased the Nod-like receptor protein 3 (NLRP3), atypical squamous cell (ASC), Caspase level and hippocampal reactive oxygen species (ROS), and prompted the activation of Epha4-mediated signaling and an inflammatory response. Conversely, electroacupuncture administration reduced these changes and prevented depression-like behaviors and cognitive impairment. Electroacupuncture also promoted hippocampal expression of Sirtuin1(SIRT1), Nuclear factor erythroid 2-like (Nrf2), Heme oxygenase-1 (HO-1); reduced the expression of interleukin-1β (IL-1β), interleukin-18 (IL-18), and tumor necrosis factor-alpha (TNF-α); and prevented neural damage, particularly the synaptic myelin sheath, and neuroinflammation by regulating Eph receptor A4 (EphA4) in the hippocampal.

CONCLUSION

These results indicate that electroacupuncture prevents depression-like behaviors with cognitive impairment and synaptic and neuronal damage, probably by reducing EphA4, which mediates ROS hyperfunction and the inflammatory response.

The link between impaired oxygen supply and cognitive decline in peripheral artery disease

Although peripheral artery disease (PAD) primarily affects large arteries outside the brain, PAD is also associated with elevated cerebral vulnerabilities, including greater risks for brain injury (such as stroke), cognitive decline and dementia. In the present review, we aim to evaluate recent literature and extract information on potential mechanisms linking PAD and consequences on the brain. Furthermore, we suggest novel therapeutic avenues to mitigate cognitive decline and reduce risk of brain injury in patients with PAD. Various interventions, notably exercise, directly or indirectly improve systemic blood flow and oxygen supply and are effective strategies in patients with PAD or cognitive decline. Moreover, triggering protective cellular and systemic mechanisms by modulating inspired oxygen concentrations are emerging as potential novel treatment strategies. While several genetic and pharmacological approaches to modulate adaptations to hypoxia showed promising results in preclinical models of PAD, no clear benefits have yet been clinically demonstrated. We argue that genetic/pharmacological regulation of the involved adaptive systems remains challenging but that therapeutic variation of inspired oxygen levels (e.g., hypoxia conditioning) are promising future interventions to mitigate associated cognitive decline in patients with PAD.

Does acupuncture have advantages in the rehabilitation of vascular mild cognitive impairment? A systematic review and meta-analysis

Background

Vascular mild cognitive impairment (VMCI) is a common impairment caused by vascular factors. VMCI often occurs after stroke, and it is the main clinical manifestation of long-term disability. Many patients are treated with acupuncture in combination with other therapies. However, evidence regarding the effectiveness of this treatment regimen is lacking.

Aims

This meta-analysis aimed to evaluate the efficacy of acupuncture therapy for treating VMCI.

Methods

This systematic review was conducted in accordance with the preferred reporting and meta-analysis guidelines. The CNKI, Wanfang, VIP, CBM, Cochrane Library, PubMed and Embase databases were searched from inception to August 20, 2022. After two researchers independently screened the literature, they extracted the data and evaluated the risk of bias in the included studies. Revman 5.3 software was used for the meta-analysis.

Summary of review

Thirty-two randomized controlled trials (RCTs) were included. The overall effective rate of acupuncture for treating VMCI was 3.06, 95% CI [2.39, 3.91], (P < 0.05). Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE), Barthel Index and Activities of Daily Living (ADLs) scores significantly differed between the treatment and control groups, with weighted mean differences (WMDs) [95% CI] (P value) of 1.97 [1.44, 2.49] (P < 0.05), 2.02 [1.50, 2.54] (P < 0.05), 5.54 [3.81, 7.28] (P < 0.05), and 3.43 [2.53, 4.33] (P < 0.05), respectively. The overall effective rate of electroacupuncture (EA) for treating VMCI was better than that of the control group (RR = 2.25, 95% CI, [1.13, 4.50], P < 0.05). MoCA, MMSE, Barthel index and ADL scores differed significantly between the treatment and control groups, with WMDs [95% CI] (P value) of 1.79 [1.20, 2.38] (P < 0.05), 1.45 [0.87, 2.03] (P < 0.05), 5.78 [2.38, 9.18] (P < 0.05), and 3.15 [2.15, 4.15] (P < 0.05), respectively. Acupuncture alone and combined with drug therapy were thus superior to drug therapy alone for improving cognitive function. EA also has potential advantages.

Conclusions

Acupuncture combined with another therapy is better than other therapies alone, such as simple drug therapy, for treating VMCI. However, variations in study duration (4-12 weeks) limit us from drawing any definitive conclusions about long-term effects. Therefore, more RCTs with rigorous designs and reasonable treatment and follow-up durations are needed.

Nonpharmacological modulation of cortical spreading depolarization

AIMS

Cortical spreading depolarization (CSD) is a wave of pathologic neuronal dysfunction that spreads through cerebral gray matter, causing neurologic disturbance in migraine and promoting lesion development in acute brain injury. Pharmacologic interventions have been found to be effective in migraine with aura, but their efficacy in acutely injured brains may be limited. This necessitates the assessment of possible adjunctive treatments, such as nonpharmacologic methods. This review aims to summarize currently available nonpharmacological techniques for modulating CSDs, present their mechanisms of action, and provide insight and future directions for CSD treatment.

MAIN METHODS

A systematic literature review was performed, generating 22 articles across 3 decades. Relevant data is broken down according to method of treatment.

KEY FINDINGS

Both pharmacologic and nonpharmacologic interventions can mitigate the pathological impact of CSDs via shared molecular mechanisms, including modulating K⁺/Ca²⁺/Na⁺/Cl^- ion channels and NMDA, GABA_A, serotonin, and CGRP ligand-based receptors and decreasing microglial activation. Preclinical evidence suggests that nonpharmacologic interventions, including neuromodulation, physical exercise, therapeutic hypothermia, and lifestyle changes can also target unique mechanisms, such as increasing adrenergic tone and myelination and modulating membrane fluidity, which may lend broader modulatory effects. Collectively, these mechanisms increase the electrical initiation threshold, increase CSD latency, slow CSD velocity, and decrease CSD amplitude and duration.

SIGNIFICANCE

Given the harmful consequences of CSDs, limitations of current pharmacological interventions to inhibit CSDs in acutely injured brains, and translational potentials of nonpharmacologic interventions to modulate CSDs, further assessment of nonpharmacologic modalities and their mechanisms to mitigate CSD-related neurologic dysfunction is warranted.

The neuroprotective and neural circuit mechanisms of acupoint stimulation for cognitive impairment

Cognitive impairment is a prevalent neurological disorder that burdens families and the healthcare system. Current conventional therapies for cognitive impairment, such as cholinesterase inhibitors and N-methyl-d-aspartate receptor antagonists, are unable to completely stop or reverse the progression of the disease. Also, these medicines may cause serious problems with the digestive system, cardiovascular system, and sleep. Clinically, stimulation of acupoints has the potential to ameliorate the common symptoms of a variety of cognitive disorders, such as memory deficit, language dysfunction, executive dysfunction, reduced ability to live independently, etc. There are common acupoint stimulation mechanisms for treating various types of cognitive impairment, but few systematic analyses of the underlying mechanisms in this domain have been performed. This study comprehensively reviewed the basic research from the last 20 years and found that acupoint stimulation can effectively improve the spatial learning and memory of animals. The common mechanism may be that acupoint stimulation protects hippocampal neurons by preventing apoptosis and scavenging toxic proteins. Additionally, acupoint stimulation has antioxidant and anti-inflammatory effects, promoting neural regeneration, regulating synaptic plasticity, and normalizing neural circuits by restoring brain functional activity and connectivity. Acupoint stimulation also inhibits the production of amyloid β-peptide and the phosphorylation of Tau protein, suggesting that it may protect neurons by promoting correct protein folding and regulating the degradation of toxic proteins via the autophagy-lysosomal pathway. However, the benefits of acupoint stimulation still need to be further explored in more high-quality studies in the future.

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.

Electroacupuncture Pretreatment Prevents Cognitive Impairment Induced by Cerebral Ischemia-Reperfusion via Adenosine A1 Receptors in Rats

A previous study has demonstrated that pretreatment with electroacupuncture (EA) induces rapid tolerance to focal cerebral ischemia. In the present study, we investigated whether adenosine receptor 1 (A1 R) is involved in EA pretreatment-induced cognitive impairment after focal cerebral ischemia in rats. Two hours after EA pretreatment, focal cerebral ischemia was induced by middle cerebral artery occlusion for 120 min in male Sprague-Dawley rats. The neurobehavioral score, cognitive function [as determined by the Morris water maze (MWM) test], neuronal number, and the Bax/Bcl-2 ratio was evaluated at 24 h after reperfusion in the presence or absence of CCPA (a selective A1 receptor agonist), DPCPX (a selective A1 receptor antagonist) into left lateral ventricle, or A1 short interfering RNA into the hippocampus area. The expression of the A1 receptor in the hippocampus was also investigated. The result showed that EA pretreatment upregulated the neuronal expression of the A1 receptor in the rat hippocampus at 90 min. And EA pretreatment reversed cognitive impairment, improved neurological outcome, and inhibited apoptosis at 24 h after reperfusion. Pretreatment with CCPA could imitate the beneficial effects of EA pretreatment. But the EA pretreatment effects were abolished by DPCPX. Furthermore, A1 receptor protein was reduced by A1 short interfering RNA which attenuated EA pretreatment-induced cognitive impairment.

Mechanism underlying treatment of ischemic stroke using acupuncture: transmission and regulation

The inflammatory response after cerebral ischemia/reperfusion is an important cause of neurological damage and repair. After cerebral ischemia/reperfusion, microglia are activated, and a large number of circulating inflammatory cells infiltrate the affected area. This leads to the secretion of inflammatory mediators and an inflammatory cascade that eventually causes secondary brain damage, including neuron necrosis, blood-brain barrier destruction, cerebral edema, and an oxidative stress response. Activation of inflammatory signaling pathways plays a key role in the pathological process of ischemic stroke. Increasing evidence suggests that acupuncture can reduce the inflammatory response after cerebral ischemia/reperfusion and promote repair of the injured nervous system. Acupuncture can not only inhibit the activation and infiltration of inflammatory cells, but can also regulate the expression of inflammation-related cytokines, balance the effects of pro-inflammatory and anti-inflammatory factors, and interfere with inflammatory signaling pathways. Therefore, it is important to study the transmission and regulatory mechanism of inflammatory signaling pathways after acupuncture treatment for cerebral ischemia/reperfusion injury to provide a theoretical basis for clinical treatment of this type of injury using acupuncture. Our review summarizes the overall conditions of inflammatory cells, mediators, and pathways after cerebral ischemia/reperfusion, and discusses the possible synergistic intervention of acupuncture in the inflammatory signaling pathway network to provide a foundation to explore the multiple molecular mechanisms by which acupuncture promotes nerve function restoration.

Electroacupuncture Attenuates Inflammation after Ischemic Stroke by Inhibiting NF-κB-Mediated Activation of Microglia

Microglial activation and microglia-mediated inflammation play an important role in the occurrence, development, and outcome of stroke. Brain injury induces the activation and release of proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin- (IL-) 1β, and IL-6. Many studies have confirmed that acupuncture is effective in treating ischemic stroke. However, its protective mechanism against ischemic brain injury is complex and multifactorial. In this study, we observed the effects of electroacupuncture at Baihui (GV20) and Dazhui (GV14) on microglial activation and inflammation in the cortical ischemic penumbra (IP) of permanent middle cerebral artery occlusion (pMCAO) rats. It was found that electroacupuncture inhibited the degeneration and necrosis of microglia in the cortical IP and ameliorated mitochondrial damage. Immunofluorescence and western blot analysis showed that microglia were in a resting state or weakly activated in the normal brain. After cerebral ischemia, the expression of microglial markers (Iba-1 and CD11b) increased, and NF-κB p65, IL-1β, and TNF-α expression gradually increased. The dynamic changes were generally temporally consistent. Electroacupuncture downregulated the expressions of Iba-1 and CD11b. Additionally, it inhibited the expression of NF-κB p65, IL-1β, and TNF-α and reduced the conversion of microglia to the M1 phenotype after ischemia. Electroacupuncture regulated the activation of microglia and microglia-mediated inflammation after cerebral ischemia, confirming the relevant theories regarding the effect of acupuncture treatment on cerebral ischemia and guiding clinical practice.

Electroacupuncture pre‑conditioning protects from lung injury induced by limb ischemia/reperfusion through TLR4 and NF‑κB in rats

Limb ischemia/reperfusion (I/R) can induce inflammation, causing acute lung injury. The Toll-like receptor 4 (TLR4)/NF-κB pathway plays an important role in acute and chronic inflammatory disorders. Several studies have demonstrated the efficacy of acupuncture in lung inflammatory injury. The aim of the present study was to elucidate the mechanism underlying the protective effect of electroacupuncture (EA) against lung injury induced by limb I/R. EA applied at the Zusanli and Sanyinjiao acupoints attenuated lung injury and decreased the secretion of inflammatory factors such as tumor necrosis factor-α, interleukin (IL)-1, IL-6 and myeloperoxidase. Moreover, the expression levels of TLR4 and NF-κB were suppressed by EA. Thus, the present findings suggested that EA can reduce pulmonary inflammation induced by limb I/R injury, possibly via the inhibition of the TLR4/NF-κB pathway.

The Role of Melatonin in Electroacupuncture Alleviating Lung Injury Induced by Limb Ischemia-Reperfusion in Rabbits

Background

Our previous studies have shown that electroacupuncture (EA) can alleviate lung injury induced by limb ischemia-reperfusion, but the specific mechanism is still unclear.

Material/Methods

The animals were randomly divided into sham operation group (Sham), model group (IR), electroacupuncture group (EA), sham electroacupuncture group (SEA), and EA+luzindole group (EA+luzindole). The limb ischemia-reperfusion model was established according to previously described, the rabbits in the EA and EA+luzindole groups were given EA at ST36 and BL13 for 7 days before the model preparation and during the model implementation, however, sham EA was mainly used to stimulate the rabbits in the SEA group with shallow needling at the points 0.5 cm near ST36 and BL13. Then, 30 mg/kg of luzindole was intraperitoneally injected 30 minutes before the model preparation in the EA+luzindole group.

Results

The wet weight/dry weight (W/D) ratio, lung injury score, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and malondialdehyde (MDA) contents in the EA group at 4 hours after reperfusion were significantly lower than those in the IR, SEA, and EA+luzindole groups. The levels of serum melatonin at T0 in the EA and EA+luzindole groups were significantly higher than those in the Sham group. The levels of serum melatonin at T1 and T2 in the IR group were significantly lower than those in the Sham group. There was no significant difference in the expression levels of melatonin receptor 1 (MR-1) and MR-2 in lung tissues among the 5 groups.

Conclusions

EA could alleviate the lung injury induced by limb ischemia-reperfusion by promoting the secretion of melatonin, while having no effect on the expression of melatonin receptor in lung tissues.

Improvement of asthma control after laser acupuncture and its impact on exhaled 8-isoprostane as an oxidative biomarker in chronic bronchial asthma

Traditional medicine may not control bronchial asthma. Many patients have uncontrolled symptoms and the underlying ongoing inflammation is persistent.

OBJECTIVE

to assess efficacy of laser acupuncture in improving asthma symptoms and underlying oxidative stress through monitoring exhaled 8-isoprostane.

METHOD

48 asthmatic (case group) received successive low level laser acupuncture sessions to stimulate acupoints for chronic asthma and 24 asthmatics received deactivated laser acupuncture sessions (control group). Asthma symptoms, asthma control questionnaire, concentration of 8-Isoprostane in exhaled breath condensate and airway resistance were assessed before and after laser acupuncture therapy.

RESULTS

After the completion of the course of laser acupuncture therapy, we observed significant improvement of asthma symptoms. Asthma control questionnaire improved from 9.7 ± 3.3 to 21.8 ± 3.6 (p 0.001). EBC 8-Isoprostane dropped from 14.7 ± 5.4 to 8.1 ± 5.0 (p 0.001). The airway resistance at R5 and R20 significantly decreased from 116.6 ± 25.8 & 124.5 ± 31.2 to 101.5 ± 25.6 &110.9 ± 29.9 respectively (p 0.001). Control patients who received sham acupuncture therapy did not show such improvement.

CONCLUSION

Laser acupuncture is an effective modality in treating bronchial asthma as evidenced by improved symptoms, airway resistance, and oxidative biomarkers.

A mechanical acupuncture instrument mitigates the endoplasmic reticulum stress and oxidative stress of ovariectomized rats

Background

Acupuncture has become a common complementary and alternative treatment approach for anxiety and depression. However, there is little research on the detailed mechanism of acupuncture therapy relieving depression. Previously, 17β-estradiol (E2) was shown to prevent oxidative stress and endoplasmic reticulum (ER) stress in ovariectomized (OVX) rats. This study investigated whether stimulation of Sanyinjiao (SP6) using a mechanical acupuncture instrument can alleviate depression-like behavior caused by estrogen deficiency in OVX rats. Furthermore, we found that acupuncture reduced ER stress and oxidative stress-related proteins expression.

Methods

The OVX operation was performed on female SD rats that were separated into four groups: The E2 (2.5 μg/kg, i.p.) injection group (OVX + E2), the OVX group (OVX), and the OVX with acupuncture stimulation group (OVX + SP6). Non-acupoint stimulation group (OVX + NonAcu). The acupuncture point stimulation began three weeks after surgery. The depressive behavior was analyzed by the forced swim test and open field test. The 8-OHDG, BiP, Sigma receptor 1, pJNK, PDI, Ero1-Iα and Calnexin protein levels were evaluated by immunoreactivity in the amygdala.

Results

Acupuncture stimulation reduced depressive behavior and altered depression-related proteins. Stimulation of SP6 decreased the immobility time of the FST and altered the ER stress and oxidative stress marker proteins, such as 8-OHDG, BiP, pJNK, PDI, Ero1-Ia and Calnexin.

Conclusion

Our results indicated that acupuncture at SP6 showed a significant antidepressant-like effect on an OVX-induced depression rat model by mitigation of ER stress and oxidative stress in amygdala.

Electroacupuncture Pretreatment Ameliorates PTSD-Like Behaviors in Rats by Enhancing Hippocampal Neurogenesis via the Keap1/Nrf2 Antioxidant Signaling Pathway

Electroacupuncture (EA) pretreatment is a clinically useful therapy for several brain disorders. However, whether and via which exact molecular mechanisms it ameliorates post-traumatic stress disorder (PTSD) remains unclear. In the present study, rats received EA stimulation for seven consecutive days before exposure to enhanced single prolonged stress (ESPS). Anxiety-like and fear learning behaviors; hippocampal neurogenesis; the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), Kelch-like ECH-associated protein 1 (keap1), and heme oxygenase 1 (HO-1); and the activity of AMP-activated kinase (AMPK) were evaluated at 14 days after ESPS. EA pretreatment improved hippocampal neurogenesis and ameliorated anxiety-like behaviors in ESPS-treated rats. EA pretreatment also increased the expression of Nrf2 and HO-1 and the activity of AMPK. Furthermore, Nrf2 knockdown by a short hairpin RNA affected anxiety-like behaviors and expression of neuroprotective markers (BDNF, DCX) in a manner similar to ESPS alone and dampened the neuroprotective effects of EA pretreatment. In contrast, Keap1 knockdown increased the expression of HO-1, improved hippocampal neurogenesis, and alleviated PTSD-like behaviors. Altogether, our results suggest that EA pretreatment ameliorates ESPS-induced anxiety-like behaviors and prevents hippocampal neurogenesis disruption in a rat model of PTSD possibly through regulation of the keap1/Nrf2 antioxidant defense pathway.

Renal ischemia/reperfusion induced learning and memory deficit in the rat: Insights into underlying molecular and cellular mechanisms

Distance organ dysfunction is the major cause of death in the patients with acute kidney injury (AKI). However, the neurobiological basis of AKI-induced brain disorders and their mediators are poorly understood. This study was aimed to find out the links between AKI and brain injury and also the underlying cellular and electrophysiological mechanisms of memory deficit following induction of AKI via different experimental models of renal ischemia with or without uremia and uremia without renal ischemia. Fifty four male Sprague-Dawley rats were divided into 4 groups that underwent 1-h bilateral or 2-h unilateral renal ischemia followed by 1-day reperfusion (BIR and UIR, respectively), and 1-day following bilateral nephrectomy (BNX) or sham-operation. There were 2 subgroups in each group, which blood-brain barrier (BBB) integrity was evaluated in one subgroup. The other subgroup was used for recordings electrophysiological activities of the hippocampus; and after blood sampling and sacrificing animal, the cerebral hemispheres were removed and preserved for performing stereological study and Western-blotting of caspase-3 in the left and right hippocampus, respectively. Plasma urea and creatinine and CA1 neuronal loss were largely increased by BNX and BIR, but slightly by UIR. Apoptosis was stimulated in the hippocampus intensively by BIR but moderately by UIR and BNX. However, BIR and UIR were associated with profoundly disturbed BBB, increased CA1 neuronal excitability, impaired LTP induction and memory deficit. Therefore, AKI most likely through inflammatory mediators leads to hippocampal apoptosis and electrophysiological impairments, BBB disruption and memory loss, whereas uremia may contribute to necrotic neuronal death.

Beneficial Effect of Exercise on Cognitive Function during Peripheral Arterial Disease: Potential Involvement of Myokines and Microglial Anti-Inflammatory Phenotype Enhancement

Peripheral arterial disease (PAD), leading to intermittent claudication, critical ischemia with rest pain, and/or tissue damage, is a public health issue associated with significant morbidity and mortality. Little is known about the link between PAD, cognitive function, and whether exercise might reduce cognitive dysfunction in PAD patients, as previously observed concerning both quality of life and prognosis. This review highlights the fact that patients suffering from PAD often demonstrate cognitive dysfunction characterized by reduced performance in nonverbal reasoning, reduced verbal fluency, and decreased information processing speed and a greater risk for progression toward dementia. Further, the data presented support that physical exercise, likely through myokine secretion and microglial anti-inflammatory phenotype enhancement, might participate in the cognition protection in common clinical settings.

Cognitive improvement effects of electro-acupuncture for the treatment of MCI compared with Western medications: a systematic review and Meta-analysis

BACKGROUND

Almost half of mild cognitive impairment (MCI) patients progress to dementia, which is associated with decreased quality of life and obstacles to independent living. Relevant management is expected to prevent MCI patients from progressing to dementia. In recent years, electroacupuncture (EA) has been used to treat various kinds of neurological disorders including MCI. This study evaluates the use of EA for MCI patients to increase cognitive function through a comparison with Western medications.

METHODS

Randomized controlled trials (RCT) or systematical reviews (SR) of EA versus Western medications for MCI were searched using the following 10 databases: Pubmed, Cochrane Library, CINAHL, EMBASE, China National Knowledge Infrastructure (CNKI), National Digital Science Library (NDSL), Journal of Oriental Neuropsychiatry (JON), Korean Medical Database (KMBASE), KoreaMed, and OASIS, from October 2007 to August 2017, without language restriction. A methodological quality assessment of RCTs or SRs that met inclusion criteria was conducted using Cochrane Risk of bias (RoB) tool and a meta-analysis by RevMan (Review Manager) 5.3.5 version of Cochrane collaboration.

RESULTS

Five RCTs with 257 patients met inclusion criteria and those were randomly divided into two groups: the EA group (n = 103) and Western medications group (n = 154). The methodological quality of the included studies showed high risk or/and unclear of risk of bias. The meta-analysis of five studies reported that the EA group was better than the Western medications group, improving the Mini Mental State Examination (MMSE) score by 0.65 [95% CI 0.28~1.01] higher mean difference, Montreal Cognitive Assessment (MoCA) score by 0.66 [95% CI 0.00~1.32] higher mean difference. Adverse effects were not reported in the selected studies.

CONCLUSION

Electroacupuncture was an effective treatment for MCI patients by improving cognitive function. However, the included studies presented a low methodological quality and no adverse effects were reported. Thus, further comprehensive studies with a design in depth are needed to derive significant results.

Rat hippocampal CA3 neuronal injury induced by limb ischemia/reperfusion: A possible restorative effect of alpha lipoic acid

Limb ischemia reperfusion (I/R) injury is associated with serious local and systemic effects. Reperfusion may augment tissue injury in excess of that produced by ischemia alone. The hippocampus has been reported to be vulnerable to I/R injury. Alpha lipoic acid (ALA) is an endogenous antioxidant with a powerful antioxidative, anti-inflammatory, and antiapoptotic properties. We studied the probable restorative effect of ALA on limb I/R-induced structural damage of rat hippocampus. Forty adult male albino rats were divided equally into four groups: group I (sham); group II (I/R-1 day) has undergone bilateral femoral arteries occlusion (3 h), then reperfusion for 1 day; group III (I/R-7 days) has undergone reperfusion for seven days; group IV (I/R-ALA) has undergone I/R as group III and received an intraperitoneal injection of ALA (100 mg/kg) for 7 days. I/R groups revealed degenerative changes in the pyramidal neuronal perikarya of CA3 field in the form of dark-stained cytoplasm, dilated RER cisternae, mitochondrial alterations, and dense bodies' accumulation. Their dendrites showed disorganized microtubules. Astrogliosis is featured by an increased number and increased immunoreactivity of astrocytes for glial fibrillary acid protein. Morphometric data revealed significant reduction of light neurons, surface area of neurons, and thickness of the CA3 layer. Most blood capillaries exhibited narrow lumen and irregular basal lamina. ALA ameliorated the neuronal damage. Pyramidal neurons revealed preservation of normal structure. Significant increase in the thickness of pyramidal layer in CA3 field and surface area and number of light neurons was observed but astrogliosis persisted. Limb I/R had a deleterious remote effect on the hippocampus aggravated with longer period of reperfusion. This work may encourage the use of ALA in the critical clinical settings with I/R injury.

Chrysophanol attenuates nitrosative/oxidative stress injury in a mouse model of focal cerebral ischemia/reperfusion

Nitrosative/oxidative stress plays an important role in neuronal death following cerebral ischemia/reperfusion (I/R). Chrysophanol (CHR) has been shown to afford significant neuroprotection on ischemic stroke, however, whether its mechanism is related to attenuating nitrosative/oxidative stress is not clear. In the present study, we investigated the effect of CHR on neuronal injury related to nitric oxide (NO) production by using mouse middle cerebral artery occlusion (MCAO) model. Our results revealed that nitrite plus nitrate (NO_x^-) and 3-nitrotyrosine (3-NT) levels increased in ischemic brain 14 days after reperfusion, and were subsequently attenuated by CHR treatment. Moreover, 3-NT is colocalized with NeuN and TUNEL, suggesting that neuronal apoptosis following I/R is associated with 3-NT and CHR suppresses NO-associated neuronal cell death. Accordingly, cleaved caspase-3 expression in ischemic brain was decreased by CHR treatment. I/R also decreased the activity of total superoxide dismutase (SOD) and manganese-dependent SOD (MnSOD), whilst increased reactive oxygen species (ROS) production significantly. Interestingly, CHR reversed this decrease in total SOD, and MnSOD activity, and inhibited ROS generation in the ischemic brain. Taken together, our results provide direct evidence suggesting that CHR attenuates nitrosative/oxidative stress injury induced by I/R, providing a novel therapeutic target in the treatment of acute ischemic stroke.

Acupuncture at ST36 exerts neuroprotective effects via inhibition of reactive astrogliosis in infantile rats with hydrocephalus

BACKGROUND

Acupuncture has been associated with improved cerebral circulation, analgesia, neuromodulatory function and neurogenesis. In particular, acupuncture at ST36 has been widely used in several central nervous system (CNS) disorders, including neurodegenerative diseases. However, its effects on hydrocephalus have not been studied. Our aim was to evaluate the effects of acupuncture at ST36 on behaviour, motor development and reactive astrogliosis in infantile rats with hydrocephalus.

METHODS

Hydrocephalus was induced in sixteen 7-day-old pup rats by injection of 20% kaolin into the cisterna magna. One day after hydrocephalus induction, acupuncture was applied once daily (for 30 min) for a total of 21 days in eight randomly selected animals (HAc group) while the remaining eight remained untreated (H group). An additional eight healthy animals were included as controls (C group). All animals were weighed daily and, from the fifth day after hydrocephalus induction, underwent MRI to determine the ventricular ratio (VR). Rats were also exposed to modified open-field tests every 3 days until the end of the experiment. After 21 days all the animals were euthanased and their brains removed for histology and immunohistochemistry.

RESULTS

Hydrocephalic rats showed an increase in VR when compared with control rats (P<0.01). In addition, these animals exhibited delayed weight gain, which was attenuated with acupuncture treatment. Hydrocephalic animals treated with acupuncture performed better in open field tests (P<0.05), and had a reduction in reactive astrocyte cell density in the corpus callosum and external capsule, as assessed by GFAP (glial fibrillary acidic protein) immunohistochemistry (P<0.05).

CONCLUSIONS

These findings indicate that acupuncture at ST36 has a neuroprotective potential mediated, in part, by inhibition of astrogliosis.

Electroacupuncture Inhibits Apoptosis of Peri-Ischemic Regions via Modulating p38, Extracellular Signal-Regulated Kinase (ERK1/2), and c-Jun N Terminal Kinases (JNK) in Cerebral Ischemia-Reperfusion-Injured Rats

BACKGROUND Previous studies suggested that inhibition of apoptosis prevents the dysfunction of ischemia-reperfusion injury. In the pathogenesis of ischemia-reperfusion injury, JNK/ERK1/2 and p38 play an essential role in regulation of cell apoptosis. Electroacupuncture (EA), a form of acupuncture, has demonstrated superiority in preventing ischemia-reperfusion injury, but the underlying mechanism is unclear. In the present study, we explored the effects of electroacupuncture at Shenting (GV24) and Baihui (GV20) acupoints on focal cerebral ischemia-reperfusion (MCAO) rats, and explored whether JNK/ERK1/2- and p38-mediated cell apoptosis are involved. MATERIAL AND METHODS The rats were divided into a sham operation control group, an ischemia group, and an electroacupuncture group with acupuncture applied for 10 days (30 min per day). TTC staining was used to calculate the ischemic brain volume. TUNEL staining and transmission electron microscopy were used to detect cell apoptosis. Western blot analysis and Bio-Plex were used to detect JNK, p38, ERK1/2, Bcl-2, and Bax protein expression. RESULTS We found that electroacupuncture at day 10 significantly reduced cerebral infarction. In addition, electroacupuncture suppressed activation of JNK and p38, while enhancing the activation of ERK1/2 in the peri-ischemic regions. Consequently, the effect of electroacupuncture on these pathways resulted in the inhibition of apoptosis, which was demonstrated by TUNEL and transmission electron microscopy. We found that electroacupuncture upregulated the anti-apoptotic Bcl-2/Bax ratio in peri-ischemic regions. CONCLUSIONS Our findings suggest that inhibition of cell apoptosis via regulating multiple signaling pathways might be a mechanism whereby electroacupuncture has a positive therapeutic effect on post-stroke impairment.

Electroacupuncture therapy in inflammation regulation: current perspectives

Although acupuncture therapy is increasingly used to treat diverse symptoms and disorders in humans, its underlying mechanism is not known well. Only recently have experimental studies begun to provide insights into how acupuncture stimulation generates and relates to pathophysiological responsiveness. Acupuncture intervention is frequently used to control pathologic symptoms in several visceral organs, and a growing number of studies using experimental animal models suggest that acupuncture stimulation may be involved in inducing anti-inflammatory responses. The vagus nerve, a principal parasympathetic nerve connecting neurons in the central nervous system to cardiovascular systems and a majority of visceral organs, is known to modulate neuroimmune communication and anti-inflammatory responses in target organs. Here, we review a broad range of experimental studies demonstrating anti-inflammatory effects of electroacupuncture in pathologic animal models of cardiovascular and visceral organs and also ischemic brains. Then, we provide recent progress on the role of autonomic nerve activity in anti-inflammation mediated by electroacupuncture. We also discuss a perspective on the role of sensory signals generated by acupuncture stimulation, which may induce a neural code unique to acupuncture in the central nervous system.

Interaction between astrocytic colony stimulating factor and its receptor on microglia mediates central sensitization and behavioral hypersensitivity in chronic post ischemic pain model

Accumulation of microglia occurs in the dorsal horn in the rodent model of chronic post ischemic pain (CPIP), while the mechanism how microglia affects the development of persistent pain largely remains unknown. Here, using a rodent model of CPIP induced by ischemia-reperfusion (IR) injury in the hindpaw, we observed that microglial accumulation occurred in the ipsilateral dorsal horn after ischemia 3h, and in ipsilateral and contralateral dorsal horn in the rats with ischemia 6h. The accumulated microglia released BDNF, increased neuronal excitability in dorsal horn, and produced pain behaviors in the modeled rodents. We also found significantly increased signaling mediated by astrocytic colony-stimulating factor-1 (CSF1) and microglial CSF1 receptor (CSF1R) in dorsal horn in the ischemia 6h modeled rats. While exogenous M-CSF induced microglial activation and proliferation, BDNF production, neuronal hyperactivity in dorsal horn and behavioral hypersensitivity in the naïve rats, inhibition of astrocytic CSF1/microglial CSF1R signaling by fluorocitric or PLX3397 significantly suppressed microglial activation and proliferation, BDNF upregulation, and neuronal activity in dorsal horn, as well as the mechanical allodynia and thermal hyperalgesia, in the rats with ischemia 6h. Collectively, these results demonstrated that glial CSF1/CSF1R pathway mediated the microglial activation and proliferation, which facilitated the nociceptive output and contributed to the chronic pain induced by IR injury.

Electroacupuncture attenuates learning and memory impairment via activation of α7nAChR-mediated anti-inflammatory activity in focal cerebral ischemia/reperfusion injured rats

Studies have reported that electroacupuncture (EA) may reduce learning and memory impairment following cerebral ischemic injury. However, the precise mechanism of action remains unclear. In the present study, the attenuation of focal cerebral ischemia/reperfusion injury by EA in rats was investigated. EA at the Baihui (DU 20) and Shenting (DU 24) acupoints was demonstrated to significantly improve performance in the Morris water maze task, with shortened latency time and increased frequency of passing the platform. Molecular analysis revealed that EA activated the expression of α7 nicotinic acetylcholine receptors (α7nAChR) in the hippocampus. In addition, EA led to a decreased expression of the microglia/macrophage marker Iba1 and the astrocyte marker glial fibrillary acidic protein in the hippocampus. EA treatment also led to decreased production of the inflammatory cytokines tumor necrosis factor-α and interleukin-1β. Treatment with methyllycaconitine, an α7nAChR antagonist, attenuated the improvement of learning and memory following EA treatment and the inhibitory effects of EA on glial cell activation and inflammatory cytokine production. In conclusion, the findings of the present study demonstrate that EA is able to improve learning and memory function following cerebral ischemic injury via activation of α7nAChR, which significantly decreases the neuroinflammatory response.

Electroacupuncture pretreatment attenuates spinal cord ischemia-reperfusion injury via inhibition of high-mobility group box 1 production in a LXA4 receptor-dependent manner

Paraplegia caused by spinal cord ischemia is a severe complication following surgeries in the thoracic aneurysm. HMGB1 has been recognized as a key mediator in spinal inflammatory response after spinal cord injury. Electroacupuncture (EA) pretreatment could provide neuroprotection against cerebral ischemic injury through inhibition of HMGB1 release. Therefore, the present study aims to test the hypothesis that EA pretreatment protects against spinal cord ischemia-reperfusion (I/R) injury via inhibition of HMGB1 release. Animals were pre-treated with EA stimulations 30min daily for 4 successive days, followed by 20-min spinal cord ischemia induced by using a balloon catheter placed into the aorta. We found that spinal I/R significantly increased mRNA and cytosolic protein levels of HMGB1 after reperfusion in the spinal cord. The EA-pretreated animals displayed better motor performance after reperfusion along with the decrease of apoptosis, HMGB1, TNF-α and IL-1β expressions in the spinal cord, whereas these effects by EA pretreatment was reversed by rHMGB1 administration. Furthermore, EA pretreatment attenuated the down-regulation of LXA₄ receptor (ALX) expression induced by I/R injury, while the decrease of HMGB1 release in EA-pretreated rats was reversed by the combined BOC-2 (an inhibitor of LXA₄ receptor) treatment. In conclusion, EA pretreatment may promote spinal I/R injury through the inhibition of HMGB1 release in a LXA₄ receptor-dependent manner. Our data may represent a new therapeutic technique for treating spinal cord ischemia-reperfusion injury.

Mechanisms of acupuncture on vascular dementia-A review of animal studies

Vascular dementia (VaD) is the second leading type of dementia after Alzheimer's disease plaguing the aging population. Acupuncture has served as alternative and complementary medicine in the world for a long time and its use for VaD is based on a large body of preclinical and clinical researches. The mechanisms that underlie the protective effects of acupuncture are slowly beginning to be understood. Acupuncture influences multiple aspects of the pathological process of VaD. It improves cognitive function through protecting cerebral neurons from oxidative stress, apoptosis, and neuroinflammation, regulating glucose metabolism and neurotransmitters. Acupuncture may also improve synaptic plasticity and blood vessel function. It is likely that no single factor can explain the protection provided by acupuncture. This review provides a comprehensive overview of established and recent findings in animal-based researches aiming to elucidate the complex mechanisms of acupuncture on VaD.

Effect of combined medicated thread moxibustion plus needle picking therapy of Zhuang nationality medicine on antioxidant levels in a rat model of sciatica

OBJECTIVE

To investigate the effect and underlying mechanisms of combined medicated thread moxibustion therapy plus needle picking therapy of Zhuang nationality medicine on antioxidant levels in a rat model of sciatica.

METHODS

One hundred Wistar rats, of specific pathogen free level, were randomly divided into five groups: normal control group, model group, medicated thread moxibustion group, needle picking group, and combination group. Each group contained 20 rats. In the model, medicated thread moxibustion, needle picking, and combination groups, sciatica models were established through chronic constriction injury of the sciatic nerve. After the model was established, the rats in the medicated thread moxibustion, needle picking, and combination groups were given the corresponding therapies for 21 days. The control and model groups received no treatment. Reactive oxygen species, superoxide dismutase, malondialdehyde, and total antioxidant capacity changes were determined. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit NADPH oxidases 4 (NOX4) mRNA expression and the morphology of cells were observed to detect apoptosis of gamma- aminobutyric acid ergic (GABAergic) neurons.

RESULTS

Compared with control group, reactive oxygen species and malondialdehyde levels rose significantly in the model group (P < 0.01), while superoxide dismutase and total antioxidant capacity levels were lowered (P < 0.05). Compared with the model group, reactive oxygen species and malondialdehyde decreased in the needle picking group (P < 0.05), while superoxide dismutase levels were increased (P < 0.05); reactive oxygen species and malondialdehyde significantly decreased in the combination group (P < 0.01). In addition, the model group had higher NOX4 mRNA expression than that of the control group (P < 0.05), and the combination group had lower expression levels than that of the model group (P < 0.05). Apoptosis of GABAergic neurons was observed in the model group, and was attenuated after combined therapy.

CONCLUSION

The medicated thread moxibustion therapy plus needle picking therapy of Zhuang nationality medicine can prevent oxidative damage in the rat model of sciatica via down-regulating NOX4 expression, improving antioxidant capacity, and inhibiting the oxidative damage pathway of GABAergic neurons.

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.

Neuroprotective Effects of Electroacupuncture Preventive Treatment in Senescence-Accelerated Mouse Prone 8 Mice

OBJECTIVE

To investigate the preventive treatment effects of electroacupuncture (EA) on cognitive changes and brain damage in senescence-accelerated mouse prone 8 (SAMP8) mice.

METHODS

The 5-month-old male SAMP8 and age-matched homologous normal aging mice (SAMR1) were adopted in this study. EA stimulation at Baihui (GV 20) and Yintang (EX-HN 3) was performed every other day for 12 weeks, 4 weeks as a course. Morris water maze test and Nissl-stained with cresyl violet were used for cognitive impairments evaluation and brain morphometric analysis. Amyloid-β (A β) expression in hippocampus and parietal cortex was detected by immunohistochemistry, and apoptosis was observed by TUNEL staining.

RESULTS

After 3 courses of EA preventive treatment, the escape latencies of 8-month-old SAMP8 mice in EA group were significantly shortened than those of un-pretreated SAMP8 mice. Compared with SAMR1 mice, extensive neuronal changes were visualized in the CA1 area of hippocampus in SAMP8 mice, while these pathological changes and attenuate cell loss in hippocampal CA1 area of SAMP8 mice markedly reduced after EA preventive treatment. Furthermore, A β expression in hippocampus and parietal cortex of SAMP8 mice decreased significantly after EA treatment, and neuronal apoptosis decreased as well.

CONCLUSION

EA preventive treatment at GV 20 and EX-HN 3 might improve cognitive deficits and neuropathological changes in SAMP8 mice, which might be, at least in part, due to the effects of reducing brain neuronal damage, decreasing neuronal apoptosis and inhibiting A β-containing aggregates.

Electroacupuncture preconditioning reduces ROS generation with NOX4 down-regulation and ameliorates blood-brain barrier disruption after ischemic stroke

Background

Electroacupuncture (EA) is a modern application based on combination of traditional manual acupuncture and electrotherapy that is frequently recommended as an adjuvant treatment for ischemic stroke. EA preconditioning can ameliorate blood-brain barrier (BBB) dysfunction and brain edema in ischemia-reperfusion injury; however, its mechanism remains unclear. This study investigated the preventive effects of EA preconditioning, particularly on BBB injury, followed by a transient middle cerebral artery occlusion (MCAO) model in mice.

Results

Mice were treated with EA (20 min) at Baihui (GV20) and Dazhui (GV14) acupoints once a day for 3 days before ischemic injury. Infarct volume, neurological deficits, oxidative stress, Evans blue leakage and brain edema were evaluated at 24 h after ischemia-reperfusion injury. EA preconditioning significantly decreased infarct volume and improved neurological function even after ischemic injury. In addition, both Evans blue leakage and water content were significantly reduced in EA preconditioned mice. Whereas the expression of tight junction proteins, ZO-1 and claudin-5, were remarkably increased by EA preconditioning. Mice with EA preconditioning showed the reduction of astrocytic aquaporin 4, which is involved in BBB permeabilization. In addition, we found that EA preconditioning decreased reactive oxygen species (ROS) in brain tissues after ischemic injury. The expression of NADPH oxidase 4 (NOX4), not NOX2, was significantly suppressed in EA preconditioned mice.

Conclusions

These results suggest that EA preconditioning improve neural function after ischemic injury through diminishing BBB disruption and brain edema. And, the reduction of ROS generation and NOX4 expression by EA preconditioning might be involved in BBB recovery. Therefore, EA may serve as a potential preventive strategy for patients at high risk of ischemic stroke.

Acupuncture-Induced Analgesia: The Role of Microglial Inhibition

The last three decades have documented preclinical and clinical data supporting the use of acupuncture in relieving symptoms of many diseases, including allergies, infections, and neurological disorders. The advent of electroacupuncture has not only modernized the practice of acupuncture, but also has improved its efficacy, especially for producing analgesic-like effects. Although the mechanism of action of acupuncture-induced analgesia remains largely unknown, several lines of investigation have implicated modulation of pain processes via brain opioid signaling and neuroimmunoregulatory pathways. Here, we review key findings demonstrating the efficacy and underlying mechanisms of acupuncture-induced analgesia. In particular, we discuss potent analgesic effects of acupuncture via neural pain processes through inhibition of microglial activation. The safe and effective use of acupuncture stands as a nonpharmacological alternative for induction of analgesia, which has direct clinical applications, especially for pain-related diseases.

Inhibition of reactive oxygen species downregulates the MAPK pathway in rat spinal cord after limb ischemia reperfusion injury

INTRODUCTION

We examined the activity of mitogen-activated protein kinase (MAPK) family members, extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38, in rats pinal cord after hind limb ischemia reperfusion (IR) and analyzed the role of reactive oxygen species (ROS) as mediators of MAPK signaling under these conditions.

METHODS

In experiment 1, hind limb IR rats were treated intraperitoneally with one of following agents at 30 min before reperfusion: allopurinol (4, 40 mg/kg), superoxide dismutase (SOD, 4000 U/kg), N-nitro-l-arginine methyl ester (l-NAME, 10 mg/kg), or SOD (4000 U/kg) + l-NAME (10 mg/kg). In experiment 2, 5,10,15,20-tetrakis (N-methyl-4'-pyridyl) porphyrinato iron (III) (FeTMPyP) was administered intraperitoneally (1, 3, or 10 mg/kg) 30 min before reperfusion. After 3 d reperfusion period, the spinal cord (L4-6) was harvested to investigate MAPK signaling activity.

RESULTS

In experiment 1, p-ERK and p-JNK levels were significantly higher in the IR group than sham group. Administration of allopurinol, SOD, l-NAME, or SOD + l-NAME significantly reduced the IR-induced increase in p-ERK and p-JNK levels. There were no significant differences in p-p38 levels. In experiment 2, FeTMPyP significantly reduced the IR-induced increase in p-ERK and p-JNK levels in a dose-dependent manner.

CONCLUSIONS

Activation of ERK and JNK in the spinal cord was induced by hind limb IR and was not accompanied by p38 activation. IR-induced MAPK phosphorylation was reduced by inhibition of superoxide, nitric oxide, and peroxynitrite, indicating that ROS produced by hind limb IR mediate the activation of these signaling pathways in the spinal cord, potentially affecting distant organs.

What is the Acupoint? A preliminary review of Acupoints

BACKGROUND

According to traditional Chinese medicine (TCM) theory, acupoints are specifically chosen sites of acupuncture manipulation, and also the basis for studying the mechanism of acupuncture. Stimulating different acupoints on the body surface could provide various therapeutic benefits. However, what is the acupoint? This question is not clear.

REVIEW SUMMARY

We focuse on examining the function of acupoints from different perspectives, including the local and the systemic effects of stimulating acupoints. For example, acupoints may release certain substances or incur some changes, which could adjust the function of organs, maintain homeostasis. Furthermore, the therapeutic effects of verum acupoints versus sham acupoints were discussed. However, due to insufficience in evidence and in current methodologies, research into mechanisms of acupuncture is still incomplete.

CONCLUSION

This review might explain, to some extent, what an acupoint is. Further research into the identity of acupoints is warranted, and multidisciplinary methods using novel technologies may yield significant advances over existing knowledge.

Downregulation of Spinal G Protein-Coupled Kinase 2 Abolished the Antiallodynic Effect of Electroacupuncture

Acupuncture or electroacupuncture (EA) has been demonstrated to have a powerful antihypernociceptive effect on inflammatory pain. The attenuation of G protein-coupled receptor kinase 2 (GRK2) in spinal cord and peripheral nociceptor has been widely acknowledged to promote the transition from acute to chronic pain and to facilitate the nociceptive progress. This study was designed to investigate the possible role of spinal GRK2 in EA antiallodynic in a rat model with complete Freund's adjuvant (CFA) induced inflammatory pain. EA was applied to ST36 (“Zusanli”) and BL60 (“Kunlun”) one day after CFA injection. Single EA treatment at day 1 after CFA injection remarkably alleviated CFA induced mechanical allodynia two hours after EA. Repeated EA displayed significant antiallodynic effect from 2nd EA treatment and a persistent effect was observed during the rest of treatments. However, downregulation of spinal GRK2 by intrathecal exposure of GRK2 antisense 30 mins after EA treatment completely eliminated both the transient and persistent antiallodynic effect by EA treatment. These pieces of data demonstrated that the spinal GRK2 played an important role in EA antiallodynia on inflammatory pain.

Electroacupuncture prevents cognitive impairments by regulating the early changes after brain irradiation in rats

Cognitive impairments severely affect the quality of life of patients who undergo brain irradiation, and there are no effective preventive strategies. In this study, we examined the therapeutic potential of electroacupuncture (EA) administered immediately after brain irradiation in rats. We detected changes in cognitive function, neurogenesis, and synaptic density at different time points after irradiation, but found that EA could protect the blood-brain barrier (BBB), inhibit neuroinflammatory cytokine expression, upregulate angiogenic cytokine expression, and modulate the levels of neurotransmitter receptors and neuropeptides in the early phase. Moreover, EA protected spatial memory and recognition in the delayed phase. At the cellular/molecular level, the preventative effect of EA on cognitive dysfunction was not dependent on hippocampal neurogenesis; rather, it was related to synaptophysin expression. Our results suggest that EA applied immediately after brain irradiation can prevent cognitive impairments by protecting against the early changes induced by irradiation and may be a novel approach for preventing or ameliorating cognitive impairments in patients with brain tumors who require radiotherapy.

5-hydroxymethyl-2-furfural prolongs survival and inhibits oxidative stress in a mouse model of forebrain ischemia

In the present study, we hypothesized that 5-hydroxymethyl-2-furfural could attenuate ischemic brain damage by reducing oxidative injury. Thus, mice were subjected to bilateral common carotid artery occlusion to establish a model of permanent forebrain ischemia. The mice were intraperitoneally injected with 5-hydroxymethyl-2-furfural 30 minutes before ischemia or 5 minutes after ischemia. The survival time of mice injected with 5-hydroxymethyl-2-furfural was longer compared with untreated mice. The mice subjected to ischemia for 30 minutes and reperfusion for 5 minutes were intraperitoneally injected with 5-hydroxymethyl-2-furfural 5 minutes prior to reperfusion, which increased superoxide dismutase content and reduced malondialdehyde content, similar to the effects of Edaravone, a hydroxyl radical scavenger used for the treatment of stroke. These findings indicate that intraperitoneal injection of 5-hydroxymethyl-2-furfural can prolong the survival of mice with permanent forebrain ischemia. This outcome may be mediated by its antioxidative effects.

Ginsenoside Rb1 attenuates activated microglia-induced neuronal damage

The microglia-mediated inflammatory reaction promotes neuronal damage under cerebral ischemia/hypoxia conditions. We therefore speculated that inhibition of hypoxia-induced microglial activation may alleviate neuronal damage. To test this hypothesis, we co-cultured ginsenoside Rb1, an active component of ginseng, and cortical neurons. Ginsenoside Rb1 protected neuronal morphology and structure in a single hypoxic culture system and in a hypoxic co-culture system with microglia, and reduced neuronal apoptosis and caspase-3 production. The protective effect was observable prior to placing in co-culture. Additionally, ginsenoside Rb1 inhibited levels of tumor necrosis factor-α in a co-culture system containing activated N9 microglial cells. Ginsenoside Rb1 also significantly decreased nitric oxide and superoxide production induced by N9 microglia. Our findings indicate that ginsenoside Rb1 attenuates damage to cerebral cortex neurons by downregulation of nitric oxide, superoxide, and tumor necrosis factor-α expression in hypoxia-activated microglia.

Acupuncture mechanism and redox equilibrium

Oxidative stress participates in the pathological process of various diseases. Acupuncture is a component of the health care system in China that can be traced back for at least 3000 years. Recently, increased evidences indicate that acupuncture stimulation could reduce oxidative damage in organisms under pathological state, but the exact mechanism remains unclear. This review focuses on the emerging links between acupuncture and redox modulation in various disorders, such as vascular dementia, Parkinson's disease, and hypertension, ranging from redox system, antioxidant system, anti-inflammatory system, and nervous system to signaling pathway. Although the molecular and cellular pathways studies of acupuncture effect on oxidative stress are preliminary, they represent an important step forward in the research of acupuncture antioxidative effect.

Mechanisms underlying the effect of acupuncture on cognitive improvement: a systematic review of animal studies

Acupuncture has been reported to be beneficial in treating cognitive impairment in various pathological conditions. This review describes the effort to understand the signaling pathways that underlie the acupunctural therapeutic effect on cognitive function. We searched the literature in 12 electronic databases from their inception to November 2013, with full text available and language limited to English. Twenty-three studies were identified under the selection criteria. All recruited animal studies demonstrate a significant positive effect of acupuncture on cognitive impairment. Findings suggest acupuncture may improve cognitive function through modulation of signaling pathways involved in neuronal survival and function, specifically, through promoting cholinergic neural transmission, facilitating dopaminergic synaptic transmission, enhancing neurotrophin signaling, suppressing oxidative stress, attenuating apoptosis, regulating glycometabolic enzymes and reducing microglial activation. However, the quality of reviewed studies has room for improvement. Further high-quality animal studies with randomization, blinding and estimation of sample size are needed to strengthen the recognition of group differences.

Electroacupuncture pretreatment inhibits NADPH oxidase-mediated oxidative stress in diabetic mice with cerebral ischemia

We investigated the protective effect of electroacupuncture (EA) on cerebral ischemic injury in diabetic mice, and explored the role of NADPH oxidase-mediated oxidative stress. Male C57BL/6 mice were injected streptozotocin to induce diabetes. The mice were pretreated with EA at acupoint "Baihui" for 30 min. Two hours after the end of EA pretreatment, focal cerebral ischemia was induced following 24h reperfusion. The neurobehavioral scores and infarction volumes, malondialdehyde (MDA), reactive oxygen species (ROS), and activation of NADPH oxidase were determined in the presence or absence of the NADPH oxidase inhibitor apocynin or activator tetrabromocinnamic acid (TBCA). EA pretreatment reduced infarct size and improved neurological outcomes 24h after reperfusion in the diabetic mice. EA also decreased cerebral MDA and ROS levels compared with the control group, and inhibited the NADPH oxidase activation. The beneficial effects were abolished by TBCA while pretreatment with apocynin mimicked the neuroprotective and anti-oxidative effects of EA. Our results demonstrated that EA attenuated cerebral ischemic injury by inhibiting NAPDH oxidase-mediated oxidative damage in diabetic mice. These results suggest a novel mechanism of EA pretreatment-induced tolerance in diabetic cerebral ischemia.

The neuroprotective role of acupuncture and activation of the BDNF signaling pathway

Recent studies have been conducted to examine the neuroprotective effects of acupuncture in many neurological disorders. Although the neuroprotective effects of acupuncture has been linked to changes in signaling pathways, accumulating evidence suggest the participation of endogenous biological mediators, such as the neurotrophin (NT) family of proteins, specifically, the brain derived neurotrophic factor (BDNF). Accordingly, acupuncture can inhibit neurodegeneration via expression and activation of BDNF. Moreover, recent studies have reported that acupuncture can increase ATP levels at local stimulated points. We have also demonstrated that acupuncture could activate monocytes and increase the expression of BDNF via the stimulation of ATP. The purpose of this article is to review the recent findings and ongoing studies on the neuroprotective roles of acupuncture and therapeutic implications of acupuncture-induced activation of BDNF and its signaling pathway.

Delayed brain ischemia tolerance induced by electroacupuncture pretreatment is mediated via MCP-induced protein 1

BACKGROUND

Emerging studies have demonstrated that pretreatment with electroacupuncture (EA) induces significant tolerance to focal cerebral ischemia. The present study seeks to determine the involvement of monocyte chemotactic protein-induced protein 1 (MCPIP1), a recently identified novel modulator of inflammatory reactions, in the cerebral neuroprotection conferred by EA pretreatment in the animal model of focal cerebral ischemia and to elucidate the mechanisms of EA pretreatment-induced ischemic brain tolerance.

METHODS

Twenty-four hours after the end of the last EA pretreatment, focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) for 90 minutes in male C57BL/6 mice and MCPIP1 knockout mice. Transcription and expression of MCPIP1 gene was monitored by qRT-PCR, Western blot and immunohistochemistry. The neurobehavioral scores, infarction volumes, proinflammatory cytokines and leukocyte infiltration in brain and NF-κB signaling were evaluated after ischemia/reperfusion.

RESULTS

MCPIP1 protein and mRNA levels significantly increased specifically in mouse brain undergoing EA pretreatment. EA pretreatment significantly attenuated the infarct volume, neurological deficits, upregulation of proinflammatory cytokines and leukocyte infiltration in the brain of wild-type mice after MCAO compared with that of the non-EA group. MCPIP1-deficient mice failed to evoke EA pretreatment-induced tolerance compared with that of the control MCPIP1 knockout group without EA treatment. Furthermore, the activation of NF-κB signaling was significantly reduced in EA-pretreated wild-type mice after MCAO compared to that of the non-EA control group and MCPIP1-deficient mice failed to confer the EA pretreatment-induced inhibition of NF-κB signaling after MCAO.

CONCLUSIONS

Our data demonstrated that MCPIP1 deficiency caused significant lack of EA pretreatment-induced cerebral protective effects after MCAO compared with the control group and that MCPIP1 is involved in EA pretreatment-induced delayed brain ischemia tolerance.

Ginger pharmacopuncture improves cognitive impairment and oxidative stress following cerebral ischemia

Recent findings have demonstrated that acupuncture and ginger can each improve memory impairment following cerebral ischemia. We hypothesized that ginger pharmacopuncture, a combination of these two treatments, could increase the beneficial effects. Due to the limitation of supporting evidence, we aimed to determine whether ginger pharmacopuncture could improve cognitive function and oxidative stress following cerebral ischemia. Male Wistar rats were induced by right middle cerebral artery occlusion (Rt. MCAO) and subjected to either acupuncture or ginger pharmacopuncture once daily over a period of 14 days after Rt. MCAO. Cognitive function was determined every 7 days, using escape latency and retention time as indices, and the oxidative stress status of the rats was determined at the end of the study. Rats subjected either to acupuncture or to ginger pharmacopuncture at GV20 demonstrated enhanced spatial memory, and the activities of catalase and glutathione peroxidase in both cerebral cortex and hippocampus were improved. Elevation of superoxide dismutase activity was observed only in the hippocampus. Cognitive enhancement was observed sooner with ginger pharmacopuncture than with acupuncture. The cognitive enhancing effect of acupuncture and ginger pharmacopuncture is likely to be at least partially attributable to decreased oxidative stress. However, other mechanisms may also be involved, and this requires further study.