Electroacupuncture stimulates the proliferation and differentiation of endogenous neural stem cells in a rat model of ischemic stroke

Experimental evidence-based construction of electroacupuncture for ischemic stroke: a meta-analysis and systematic review

Objective

Ischemic stroke represents a leading cause of disability and mortality worldwide, necessitating effective and complementary therapeutic strategies. Electroacupuncture (EA), a modern extension of traditional acupuncture, has garnered attention for its potential neuroprotective effects in ischemic stroke rehabilitation. This meta-analysis and systematic review aim to synthesize current experimental evidence on the efficacy of EA in ischemic stroke models, focusing on neurological outcomes, infarct volumes, and underlying molecular mechanisms.

Methods

A comprehensive search was performed across four databases-Cochrane Library, EMBASE, PubMed, and Web of Science-to identify relevant experimental studies that utilized electroacupuncture (EA) as a therapeutic modality for ischemic stroke in animal models. This search encompassed all literature available from the inception of each library through December 2023. Studies were rigorously screened based on predefined inclusion and exclusion criteria. Data on cerebral infarction volume, neurological deficit scores, cellular apoptosis, and molecular pathways were extracted and analyzed.

Results

Eleven eligible studies involving 302 animals (151 in EA treatment groups and 151 in control groups) were included. Meta-analysis revealed that EA significantly reduced cerebral infarction volumes [MD = -15.78, 95%CI (-21.40, -10.16), p < 0.05] and TUNEL-positive cells [MD = -26.46, 95%CI (-40.40, -12.51), p < 0.05], indicating reduced apoptosis. Improvements were also noted in neurological deficit scores [MD = -0.59, 95%CI (-0.92, -0.27), p < 0.05] and modified Neurological Severity Scores (mNSS) [MD = -5.68, 95%CI (-7.41, -3.95), p < 0.05], highlighting functional recovery. While the analysis showed no significant effect on caspase-3 densities [MD = -0.39, 95%CI (-0.79, 0.02), p > 0.05], a notable increase in Bcl-2 densities suggested an anti-apoptotic mechanism [MD = -0.73, 95%CI (-1.68, 0.21), p > 0.05]. The heterogeneity of the included studies points to complex underlying mechanisms, potentially involving modulation of apoptotic pathways and cerebral blood flow.

Conclusion

This meta-analysis substantiates the neuroprotective potential of EA in ischemic stroke models, primarily through apoptosis modulation and possibly through improved cerebral perfusion. These findings advocate for the integration of EA into stroke rehabilitation protocols and underscore the need for clinical trials to validate its efficacy in human subjects. Our study not only reinforces the therapeutic value of EA but also prompts further investigation into its underlying mechanisms, potentially guiding more effective stroke recovery strategies.

Systematic review and Meta-analysis of brain plasticity associated with electroacupuncture in experimental ischemic stroke

OBJECTIVE

To systematically evaluate the role of electroacupuncture in maintaining brain plasticity in ischemic stroke mediated brain damage.

METHODS

We searched for all relevant trials published through Oct 7, 2022 from seven databases. Metho-dological quality was assessed using the CAMARADES Risk of Bias Tool. A Meta-analysis of comparative effects was performed using Review Manager v.5.3 software.

RESULTS

A total of 101 studies involving 2148 animals were included. For most studies, primary outcomes results of the Meta-analysis indicate that EA significantly improved ischemic stroke rat's postsynaptic density thickness [Standardized Mean Difference (SMD) = 1.41, 95% confidence interval (CI) (0.59, 2.23), P = 0.0008], numerical density of synapses [SMD = 1.55, 95% CI (0.48, 2.63), P = 0.005] compared with non-EA-treated. Similarly, EA could improve parts of biomarkers of synapses, neurogenesis, angiogenesis and neurotrophin activity than the control group (P < 0.05).

CONCLUSION

The existing evidence suggests EA regulating ischemic stroke may be through brain plasticity. More rigorous and high quality studies should be conducted in the future.

The impact of acupuncture on neuroplasticity after ischemic stroke: a literature review and perspectives

Ischemic stroke is common in the elderly, and is one of the main causes of long-term disability worldwide. After ischemic stroke, spontaneous recovery and functional reconstruction take place. These processes are possible thanks to neuroplasticity, which involves neurogenesis, synaptogenesis, and angiogenesis. However, the repair of ischemic damage is not complete, and neurological deficits develop eventually. The WHO recommends acupuncture as an alternative and complementary method for the treatment of stroke. Moreover, clinical and experimental evidence has documented the potential of acupuncture to ameliorate ischemic stroke-induced neurological deficits, particularly sequelae such as dyskinesia, spasticity, cognitive impairment, and dysphagia. These effects are related to the ability of acupuncture to promote spontaneous neuroplasticity after ischemic stroke. Specifically, acupuncture can stimulate neurogenesis, activate axonal regeneration and sprouting, and improve the structure and function of synapses. These processes modify the neural network and function of the damaged brain area, producing the improvement of various skills and adaptability. Astrocytes and microglia may be involved in the regulation of neuroplasticity by acupuncture, such as by the production and release of a variety of neurotrophic factors, including brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF). Moreover, the evidence presented indicates that acupuncture promotes neuroplasticity by modulating the functional reconstruction of the whole brain after ischemia. Therefore, the promotion of neuroplasticity is expected to become a new target for acupuncture in the treatment of neurological deficits after ischemic stroke, and research into the mechanisms responsible for these actions will be of significant clinical value.

The roles, mechanism, and mobilization strategy of endogenous neural stem cells in brain injury

Brain injury poses a heavy disease burden in the world, resulting in chronic deficits. Therapies for brain injuries have been focused on pharmacologic, small molecule, endocrine and cell-based therapies. Endogenous neural stem cells (eNSCs) are a group of stem cells which can be activated in vivo by damage, neurotrophic factors, physical factor stimulation, and physical exercise. The activated eNSCs can proliferate, migrate and differentiate into neuron, oligodendrocyte and astrocyte, and play an important role in brain injury repair and neural plasticity. The roles of eNSCs in the repair of brain injury include but are not limited to ameliorating cognitive function, improving learning and memory function, and promoting functional gait behaviors. The activation and mobilization of eNSCs is important to the repair of injured brain. In this review we describe the current knowledge of the common character of brain injury, the roles and mechanism of eNSCs in brain injury. And then we discuss the current mobilization strategy of eNSCs following brain injury. We hope that a comprehensive awareness of the roles and mobilization strategy of eNSCs in the repair of cerebral ischemia may help to find some new therapeutic targets and strategy for treatment of stroke.

Mesenchymal Stem Cell Application and Its Therapeutic Mechanisms in Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH), a common lethal subtype of stroke accounting for nearly 10–15% of the total stroke disease and affecting two million people worldwide, has a high mortality and disability rate and, thus, a major socioeconomic burden. However, there is no effective treatment available currently. The role of mesenchymal stem cells (MSCs) in regenerative medicine is well known owing to the simplicity of acquisition from various sources, low immunogenicity, adaptation to the autogenic and allogeneic systems, immunomodulation, self-recovery by secreting extracellular vesicles (EVs), regenerative repair, and antioxidative stress. MSC therapy provides an increasingly attractive therapeutic approach for ICH. Recently, the functions of MSCs such as neuroprotection, anti-inflammation, and improvement in synaptic plasticity have been widely researched in human and rodent models of ICH. MSC transplantation has been proven to improve ICH-induced injury, including the damage of nerve cells and oligodendrocytes, the activation of microglia and astrocytes, and the destruction of blood vessels. The improvement and recovery of neurological functions in rodent ICH models were demonstrated via the mechanisms such as neurogenesis, angiogenesis, anti-inflammation, anti-apoptosis, and synaptic plasticity. Here, we discuss the pathological mechanisms following ICH and the therapeutic mechanisms of MSC-based therapy to unravel new cues for future therapeutic strategies. Furthermore, some potential strategies for enhancing the therapeutic function of MSC transplantation have also been suggested.

Repetitive transcranial magnetic stimulation increases neurological function and endogenous neural stem cell migration via the SDF-1α/CXCR4 axis after cerebral infarction in rats

Neural stem cell (NSC) migration is closely associated with brain development and is reportedly involved during recovery from ischaemic stroke. Chemokine signalling mediated by stromal cell-derived factor 1α (SDF-1α) and its receptor CXC chemokine receptor 4 (CXCR4) has been previously documented to guide the migration of NSCs. Although repetitive transcranial magnetic stimulation (rTMS) can increase neurological function in a rat stroke model, its effects on the migration of NSCs and associated underlying mechanism remain unclear. Therefore, the present study investigated the effects of rTMS on ischaemic stroke following middle cerebral artery occlusion (MCAO). All rats underwent rTMS treatment 24 h after MCAO. Neurological function, using modified Neurological Severity Scores and grip strength test and NSC migration, which were measured using immunofluorescence staining, were analysed at 7 and 14 days after MCAO, before the protein expression levels of the SDF-1α/CXCR4 axis was evaluated using western blot analysis. AMD3100, a CXCR4 inhibitor, was used to assess the effects of SDF-1α/CXCR4 signalling. In addition, neuronal survival was investigated using Nissl staining at 14 days after MCAO. It was revealed that rTMS increased the neurological recovery of rats with MCAO, facilitated the migration of NSC, augmented the expression levels of the SDF-1α/CXCR4 axis and decreased neuronal loss. Furthermore, the rTMS-induced positive responses were significantly abolished by AMD3100. Overall, these results indicated that rTMS conferred therapeutic neuroprotective properties, which can restore neurological function after ischaemic stroke, in a manner that may be associated with the activation of the SDF-1α/CXCR4 axis.

Mechanism of White Matter Injury and Promising Therapeutic Strategies of MSCs After Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is the most fatal subtype of stroke with high disability and high mortality rates, and there is no effective treatment. The predilection site of ICH is in the area of the basal ganglia and internal capsule (IC), where exist abundant white matter (WM) fiber tracts, such as the corticospinal tract (CST) in the IC. Proximal or distal white matter injury (WMI) caused by intracerebral parenchymal hemorrhage is closely associated with poor prognosis after ICH, especially motor and sensory dysfunction. The pathophysiological mechanisms involved in WMI are quite complex and still far from clear. In recent years, the neuroprotection and repairment capacity of mesenchymal stem cells (MSCs) has been widely investigated after ICH. MSCs exert many unique biological effects, including self-recovery by producing growth factors and cytokines, regenerative repair, immunomodulation, and neuroprotection against oxidative stress, providing a promising cellular therapeutic approach for the treatment of WMI. Taken together, our goal is to discuss the characteristics of WMI following ICH, including the mechanism and potential promising therapeutic targets of MSCs, aiming at providing new clues for future therapeutic strategies.

Effects of Melatonin on Neurobehavior and Cognition in a Cerebral Palsy Model of plppr5-/- Mice

Cerebral palsy (CP), a group of clinical syndromes caused by non-progressive brain damage in the developing fetus or infant, is one of the most common causes of lifelong physical disability in children in most countries. At present, many researchers believe that perinatal cerebral hypoxic ischemic injury or inflammatory injury are the main causes of cerebral palsy. Previous studies including our works confirmed that melatonin has a protective effect against convulsive brain damage during development and that it affects the expression of various molecules involved in processes such as metabolism, plasticity and signaling in the brain. Integral membrane protein plppr5 is a new member of the plasticity-related protein family, which is specifically expressed in brain and spinal cord, and induces filopodia formation as well as neurite growth. It is highly expressed in the brain, especially in areas of high plasticity, such as the hippocampus. The signals are slightly lower in the cortex, the cerebellum, and in striatum. Noteworthy, during development plppr5 mRNA is expressed in the spinal cord, i.e., in neuron rich regions such as in medial motor nuclei, suggesting that plppr5 plays an important role in the regulation of neurons. However, the existing literature only states that plppr5 is involved in the occurrence and stability of dendritic spines, and research on its possible involvement in neonatal ischemic hypoxic encephalopathy has not been previously reported. We used plppr5 knockout (plppr5-/-) mice and their wild-type littermates to establish a model of hypoxicischemic brain injury (HI) to further explore the effects of melatonin on brain injury and the role of plppr5 in this treatment in an HI model, which mainly focuses on cognition, exercise, learning, and memory. All the tests were performed at 3-4 weeks after HI. As for melatonin treatment, which was performed 5 min after HI injury and followed by every 24h. In these experiments, we found that there was a significant interaction between genotype and treatment in novel object recognition tests, surface righting reflex tests and forelimb suspension reflex tests, which represent learning and memory, motor function and coordination, and the forelimb grip of the mice, respectively. However, a significant main effect of genotype and treatment on performance in all behavioral tests were observed. Specifically, wild-type mice with HI injury performed better than plppr5-/- mice, regardless of treatment with melatonin or vehicle. Moreover, treatment with melatonin could improve behavior in the tests for wild-type mice with HI injury, but not for plppr5-/- mice. This study showed that plppr5 knockout aggravated HI damage and partially weakened the neuroprotection of melatonin in some aspects (such as novel object recognition test and partial nerve reflexes), which deserves further study.

Neuroregeneration and functional recovery after stroke: advancing neural stem cell therapy toward clinical application

Stroke is a main cause of death and disability worldwide. The ability of the brain to self-repair in the acute and chronic phases after stroke is minimal; however, promising stem cell-based interventions are emerging that may give substantial and possibly complete recovery of brain function after stroke. Many animal models and clinical trials have demonstrated that neural stem cells (NSCs) in the central nervous system can orchestrate neurological repair through nerve regeneration, neuron polarization, axon pruning, neurite outgrowth, repair of myelin, and remodeling of the microenvironment and brain networks. Compared with other types of stem cells, NSCs have unique advantages in cell replacement, paracrine action, inflammatory regulation and neuroprotection. Our review summarizes NSC origins, characteristics, therapeutic mechanisms and repair processes, then highlights current research findings and clinical evidence for NSC therapy. These results may be helpful to inform the direction of future stroke research and to guide clinical decision-making.

Effect of Different Frequencies of Electroacupuncture on Post-Stroke Dysphagia in Mice

The aim of this study was to determine the optimum frequency of electroacupuncture (EA) for the treatment of dysphagia after stroke. Male C57BL/6 J mice were randomly divided into five groups: normal, model, 2 Hz, 50 Hz, and 100 Hz groups. All mice received a photochemical ischemia, except the normal group. The EA parameters were 1 mA for 15 min, with different frequencies (2, 50, and 100 Hz) applied. After a three day treatment, neuronal activation was detected by the expression of c-Fos. A multi-channel electrophysiological technique was used to assess the discharge of contralateral neurons and the neuron types in each group. The concentration of brain-derived neurotrophic factor (BDNF) in the contralateral neurons was also examined. In addition, the dysfunction of swallowing in mice was calculated according to the lick counts and the lick-lick interval within a certain period of time. The number of c-Fos neurons (P < 0.05) and the expression of BDNF (P < 0.05) increased after the 2 Hz EA treatment. The total frequency of neuron discharge in the 2 Hz group increased compared with the model group (P < 0.05). The pattern of sorted neuron populations was similar between the normal and 2 Hz groups. Consistent with these results, the lick counts increased (P < 0.05) and the lick-lick interval decreased after the 2 Hz EA treatment, which indicated a functional improvement in swallowing. These results indicated that the 2 Hz EA treatment had a good effect on dysphagia after stroke.

The reporting quality of acupuncture for neurogenesis in experimental ischemic stroke study

Background

There is increasing evidence demonstrating the highly inadequate reporting of preclinical research in multiple scientific publications. The purpose of this study is to systematically investigate the reporting quality of acupuncture for neurogenesis in animal models of acute ischemic stroke.

Methods

We searched eight databases, including PubMed, EMBASE, CINAHL, AMED, Chinese National Knowledge Infrastructure, VIP information database, Wanfang data Information Site, and Chinese Biomedical Literature Database. The methodological quality of included studies was assessed by using the CAMARADES 10-item checklist. The STRICTA statement was modified to gear to animal acupuncture research. The reporting quality was assessed according to the ARRIVE guidelines and the modified STRICTA statement. Data were analyzed with descriptive statistics.

Results

Ultimately, 44 studies containing 2,411 subjects were identified. The overall compliance with the CAMARADES 10-item checklist has a mean of 4.3. The reporting quality indicated that the overall compliance with ARRIVE guidelines has a mean of 59.9% and with the modified STRICTA statement a mean of 71.8%. The findings suggest that the reporting quality of acupuncture for preclinical stroke was generally poor.

Conclusions

Full compliance with ARRIVE guidelines and/or modified STRICTA statement in designing, conducting and reporting preclinical acupuncture research is urgently needed in the future.