Electroacupuncture attenuates both glutamate release and hyperemia after transient ischemia in gerbils

Mobilizing endogenous neuroprotection: the mechanism of the protective effect of acupuncture on the brain after stroke

Given its high morbidity, disability, and mortality rates, ischemic stroke (IS) is a severe disease posing a substantial public health threat. Although early thrombolytic therapy is effective in IS treatment, the limited time frame for its administration presents a formidable challenge. Upon occurrence, IS triggers an ischemic cascade response, inducing the brain to generate endogenous protective mechanisms against excitotoxicity and inflammation, among other pathological processes. Stroke patients often experience limited recovery stages. As a result, activating their innate self-protective capacity [endogenous brain protection (EBP)] is essential for neurological function recovery. Acupuncture has exhibited clinical efficacy in cerebral ischemic stroke (CIS) treatment by promoting the human body's self-preservation and "Zheng Qi" (a term in traditional Chinese medicine (TCM) describing positive capabilities such as self-immunity, self-recovery, and disease prevention). According to research, acupuncture can modulate astrocyte activity, decrease oxidative stress (OS), and protect neurons by inhibiting excitotoxicity, inflammation, and apoptosis via activating endogenous protective mechanisms within the brain. Furthermore, acupuncture was found to modulate microglia transformation, thereby reducing inflammation and autoimmune responses, as well as promoting blood flow restoration by regulating the vasculature or the blood-brain barrier (BBB). However, the precise mechanism underlying these processes remains unclear. Consequently, this review aims to shed light on the potential acupuncture-induced endogenous neuroprotective mechanisms by critically examining experimental evidence on the preventive and therapeutic effects exerted by acupuncture on CIS. This review offers a theoretical foundation for acupuncture-based stroke treatment.

Acupuncture and Electroacupuncture Effects of ST-36 (Zusanli) and SP-9 (Yinlingquan) on Motor Behavior in Ischemic Gerbils

Objective

Stroke is a leading cause of death and disability worldwide. To find ways to reduce behavioral disabilities, researchers study animal models. By targeting ST-36 (Zusanli) and SP-9 (Yinlingquan), this study investigated the effects of traditional acupuncture and electroacupuncture (EA) on motor behavior in gerbils following global cerebral ischemia.

Materials and Methods

Thirty-six male gerbils were randomly assigned to 6 groups (n = 6 in each): control (C); sham-surgical (S); ischemia (I); acupuncture (Ac); EA (Ea); and sham-EA (SEa). The animals were habituated in an activity cage (AC) 72 hours before surgery. After induction of global ischemia, the Ac, Ea, and SEa groups received bilateral stimulation at ST-36 and SP-9. In the Ea group, an alternating electrical current was used. The animals were tested in the AC 4 days after surgery, and the results were analyzed by Kruskal-Wallis, followed by Dunn's posthoc test.

Results

Statistical analysis revealed increased distance traveled and sensors triggered by the I, Ea, and SEa groups, compared to the C, Ac, and S groups. The animals' movement tracks had a similar pattern between the I and Ea groups, with increased exploration along the walls of the AC. Meanwhile, the Ac, S, and SEa groups explored the AC similarly to the C group.

Conclusions

These findings suggest that acupuncture may normalize motor behavior in gerbils with ischemia and could be a promising treatment for stroke-induced motor deficits.

Potential mechanisms of acupuncture in enhancing cerebral perfusion of ischemic stroke

Ischemic stroke is the predominant cause of long-term disability and death worldwide. It is attributable to the sudden interruption of regional cerebral blood flow, resulting in brain cell death and neurological impairment. Acupuncture is a widely used adjuvant treatment for ischemic stroke in China and shows promising efficacy in clinical practice. This review mainly focused on the evidence to illustrate several possible mechanisms of acupuncture therapy on cerebral perfusion in ischemic stroke. Studies have shown that acupuncture is probably effective in the enhancement of cerebral perfusion after ischemic stroke. It promotes the improvement of hemodynamics, the release of vasoactive substances, the formation of new blood vessels, as well as the restitution of microcirculation. Multiple factors may contribute to the variability in acupuncture's therapeutic effects, including the acupoint selection, stimulation frequency and intensity, and retaining needle time. Acupuncture has the potential to become a non-pharmacological adjuvant approach to enhance cerebral perfusion in ischemic stroke. Future studies are required to gain our insight into acupuncture as well as accelerate its clinical translation.

Acupuncture and neuroregeneration in ischemic stroke

Acupuncture is potentially beneficial for post-stroke rehabilitation and is considered a promising preventive strategy for stroke. Electroacupuncture pretreatment or treatment after ischemic stroke by using appropriate electroacupuncture parameters generates neuroprotective and neuroregenerative effects that increase cerebral blood flow, regulate oxidative stress, attenuate glutamate excitotoxicity, maintain blood-brain barrier integrity, inhibit apoptosis, increase growth factor production, and induce cerebral ischemic tolerance.

Mechanisms of Acupuncture Therapy in Ischemic Stroke Rehabilitation: A Literature Review of Basic Studies

Acupuncture is recommended by the World Health Organization (WHO) as an alternative and complementary strategy for stroke treatment and for improving stroke care. Clinical trial and meta-analysis findings have demonstrated the efficacy of acupuncture in improving balance function, reducing spasticity, and increasing muscle strength and general well-being post-stroke. The mechanisms underlying the beneficial effects of acupuncture in stroke rehabilitation remain unclear. The aim of this study was to conduct a literature review, summarize the current known mechanisms in ischemic stroke rehabilitation through acupuncture and electroacupuncture (EA) therapy, and to detail the frequently used acupoints implicated in these effects. The evidence in this review indicates that five major different mechanisms are involved in the beneficial effects of acupuncture/EA on ischemic stroke rehabilitation: (1) Promotion of neurogenesis and cell proliferation in the central nervous system (CNS); (2) Regulation of cerebral blood flow in the ischemic area; (3) Anti-apoptosis in the ischemic area; (4) Regulation of neurochemicals; and, (5) Improvement of impaired long-term potentiation (LTP) and memory after stroke. The most frequently used acupoints in basic studies include Baihui (GV20), Zusanli (ST36), Quchi (LI11), Shuigou (GV26), Dazhui (GV14), and Hegu (LI4). Our findings show that acupuncture exerts a beneficial effect on ischemic stroke through modulation of different mechanisms originating in the CNS.

The endocannabinoid system, a novel and key participant in acupuncture's multiple beneficial effects

Acupuncture and its modified forms have been used to treat multiple medical conditions, but whether the diverse effects of acupuncture are intrinsically linked at the cellular and molecular level and how they might be connected have yet to be determined. Recently, an emerging role for the endocannabinoid system (ECS) in the regulation of a variety of physiological/pathological conditions has been identified. Overlap between the biological and therapeutic effects induced by ECS activation and acupuncture has facilitated investigations into the participation of ECS in the acupuncture-induced beneficial effects, which have shed light on the idea that the ECS may be a primary mediator and regulatory factor of acupuncture's beneficial effects. This review seeks to provide a comprehensive summary of the existing literature concerning the role of endocannabinoid signaling in the various effects of acupuncture, and suggests a novel notion that acupuncture may restore homeostasis under different pathological conditions by regulating similar networks of signaling pathways, resulting in the activation of different reaction cascades in specific tissues in response to pathological insults.

The neuroprotective effect of electro-acupuncture against ischemic stroke in animal model: a review

BACKGROUND

It is well established that electro-acupuncture can exert neuroprotection in animal experiments. However, the exact mechanism of electro-acupuncture against ischemic stroke is not very clear.

MATERIALS AND METHODS

Literature retrieval was performed in four databases (OVID, PUBMED, EMBASE, and ISI Web of Science), from respective inception to July 2013.

RESULTS

Series of studies have demonstrated that electro-acupuncture might be a promising method in reducing brain damage after stroke and induce brain ischemic tolerance before stroke through the promotion of angiogenesis, alleviation of the inflammatory response, regulation of the blood brain barrier (BBB), inhibition of apoptosis, and so on. Through these mechanisms, electro-acupuncture may reduce the neural damages associated with stroke.

CONCLUSION

An awareness of the benefits of acupuncture might lead more patients into accepting acupuncture therapy for the management of patients with ischemic stroke and patients with high risk of ischemic stroke.

Acupuncture therapy for stroke patients

Acupuncture is one of the most important parts of Traditional Chinese Medicine, has been used for more than 3000 years as prevention and treatment for various diseases in China as well as in adjacent regions, and is widely accepted in western countries in recent years. More and more clinical trials revealed that acupuncture shows positive effect in stroke, not only as a complementary and alternative medicine for poststroke rehabilitation but also as a preventive strategy which could induce cerebral ischemic tolerance, especially when combined with modern electrotherapy. Acupuncture has some unique characteristics, which include acupoint specificity and parameter-dependent effect. It also involves complicated mechanism to exert the beneficial effect on stroke. Series of clinical trials have shown that acupuncture primarily regulates the release of neurochemicals, hemorheology, cerebral microcirculation, metabolism, neuronal activity, and the function of specific brain region. Animal studies showed that the effects of acupuncture therapy on stroke were possibly via inhibition of postischemic inflammatory reaction, stimulation of neurogenesis and angiogenesis, and influence on neural plasticity. Mechanisms for its preconditioning effect include activity enhancement of antioxidant, regulation of the endocannabinoid system, and inhibition of apoptosis. Although being controversial, acupuncture is a promising preventive and treatment strategy for stroke, but further high-quality clinical trials would be needed to provide more confirmative evidence.

Electroacupuncture Pretreatment as a Novel Avenue to Protect Brain against Ischemia and Reperfusion Injury

Electroacupuncture (EA) pretreatment is a recent observation which has been shown to induce ischemic tolerance mimicking the ischemic pretreatment, suggesting that EA pretreatment may be a promising preventive strategy for the patients with high risk of acute ischemia/reperfusion injury. It was first described in the brain, then in the heart where EA stimulation at acupoint prior to ischemia led to neuroprotection and myocardial protection and induced rapid and delayed ischemic tolerance. Then the optimal parameters and acupoint specificity of EA pretreatment to induce protective effect were proved. Many studies have shown that protective mechanisms of EA pretreatment may involve a series of regulatory molecular pathways including activity enhancement of antioxidant, regulation of the endocannabinoid system, involvement of beta-adrenergic receptor, and postreceptor signaling pathway, inhibition of apoptosis. Recently, the neuroprotective and cardioprotective effect of EA pretreatment had been demonstrated in patients undergoing craniocerebral tumor resection or heart valve replacement surgery. Thus, the purpose of this paper is to collect the evidence for the neuroprotective effect of EA pretreatment, to summarize the proposed protective mechanisms of EA pretreatment, and to discuss the possibility of EA pretreatment as a new preventive strategy for patients with high risk of ischemia in clinic.

Potential neuroprotective effects of acupuncture stimulation on diabetes mellitus in a global ischemic rat model

Acupuncture (ACU) is known to be effective in ischemia treatment, and glutamate (GLU) excitotoxicity is an important factor in neuronal cell death. We observed the effect of ACU on cerebral blood flow (%CBF) and DeltaGLU (the changes in GLU release) in the ischemic stroke rat model of diabetic mellitus (DM). A global ischemia was induced using the eleven-vessel occlusion (11-VO) method in 14 Sprague-Dawley rats (DM), which were randomly divided into two groups: the control group and the ACU-treatment group. Extracellular DeltaGLU was assessed using an intra-cerebral biosensor system measuring 256 samples per second, simultaneously with %CBF and electroencephalogram. ACU stimulation was applied to ACU points GB34 and GB39 during the ischemic period. Twenty-three diagnostic parameters were proposed first for a detailed analysis of changes in %CBF and GLU release during ischemia/reperfusion. ACU rats showed a significant decrease in ischemic (p < 0.05) and reperfusion %CBF (p < 0.0001) than control rats, and a significantly larger decrease in ischemic DeltaGLU (p < 0.05) and peak level of reperfusion DeltaGLU (p < 0.005) than control rats. From these results, we suggest that ACU stimulation is responsible for the potential protection of neurons through suppression of %CBF response in the increased plasma osmolality and extracellular DeltaGLU in diabetic rats under ischemic conditions.

An individual variation study of electroacupuncture analgesia in rats using microarray

The aim of the present study is to probe candidate genes which were involved in the electroacupuncture (EA) analgesia and to understand the molecular basis of the individual difference of EA analgesia in rats. We compared hypothalamus transcriptional profiles of responders with those of non-responders after 1 Hz EA treatment at ST36 acupoint for 1 hour by using oligonucleotide microarray. Responders and non-responders were determined by tail flick latency (TFL). A real-time quantitative RT-PCR was applied to validate the differential expressed genes. Our study provided a global hypothalamus transcriptional profile of EA analgesia in rats. We found that 63 and 3 genes were up- and down-regulated in the responder group, respectively. Half of the differentially expressed genes were classified into 9 functional groups which were ion transport, sensory perception, synaptogenesis and synaptic transmission, signal transduction, inflammatory response, apoptosis, transcription, protein amino acid phosphorylation and G-protein signaling. Glutamatergic receptors, ghrelin precursor, melanocortin 4 receptor (MC4-R) and neuroligin 1 were found to be up-regulated in the responder group which may become new targets for nociceptive study and deserve further investigation for developing new acupuncture therapy and intervention of pain modulation.