Therapeutic effects of repetitive transcranial magnetic stimulation in an animal model of Parkinson's disease

Noninvasive Neuromodulation in Parkinson's Disease: Insights from Animal Models

The mainstay treatments for Parkinson's Disease (PD) have been limited to pharmacotherapy and deep brain stimulation. While these interventions are helpful, a new wave of research is investigating noninvasive neuromodulation methods as potential treatments. Some promising avenues have included transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), electroconvulsive therapy (ECT), and focused ultrasound (FUS). While these methods are being tested in PD patients, investigations in animal models of PD have sought to elucidate their therapeutic mechanisms. In this rapid review, we assess the available animal literature on these noninvasive techniques and discuss the possible mechanisms mediating their therapeutic effects based on these findings.

Repetitive transcranial magnetic stimulation alleviates glial activation through suppressing HMGB1/TLR4 pathway in a rat model of Parkinson's disease

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) has been demonstrated to be effective in Parkinson's disease (PD), but whether rTMS treatment has a relieving effect on neuroinflammation remains to be investigated. In this article, we explored the effects of rTMS on forelimb use asymmetry and neuroinflammation-related mechanisms in a 6-hydroxydopamine (6-OHDA)-induced PD rat model.

METHODS AND RESULTS

Rats in the 6-OHDA+rTMS group received 10 Hz rTMS daily for 4 weeks. Behavioral tests (the cylinder test) were performed at the 3rd and 7th weeks after the operation. Astrocyte and microglia activation and protein levels of tyrosine hydroxylase(TH), high-mobility group box 1(HMGB1) and toll-like receptors 4(TLR4) were investigated by immunohistochemistry and Western blot analyses, respectively. After 4 weeks of treatment, forelimb use asymmetry was ameliorated in the 6-OHDA+rTMS group. Consistent with the behavioral tests, rTMS increased TH in the substantia nigra (SN) and the striatum of PD rats. High glial activation and HMGB1/TLR4 expression in the SN and the striatum were observed in the 6-OHDA group, while rTMS alleviated these changes.

CONCLUSIONS

This study showed that rTMS might be a promising method for alleviating neuroinflammation in PD rat models, and the effects might be mediated through the downregulation of the HMGB1/TLR4 pathway.

Intermittent Theta Burst Stimulation Improves Motor and Behavioral Dysfunction through Modulation of NMDA Receptor Subunit Composition in Experimental Model of Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder characterized by the progressive degeneration of the dopaminergic system, leading to a variety of motor and nonmotor symptoms. The currently available symptomatic therapy loses efficacy over time, indicating the need for new therapeutic approaches. Repetitive transcranial magnetic stimulation (rTMS) has emerged as one of the potential candidates for PD therapy. Intermittent theta burst stimulation (iTBS), an excitatory protocol of rTMS, has been shown to be beneficial in several animal models of neurodegeneration, including PD. The aim of this study was to investigate the effects of prolonged iTBS on motor performance and behavior and the possible association with changes in the NMDAR subunit composition in the 6-hydroxydopamine (6-OHDA)-induced experimental model of PD. Two-month-old male Wistar rats were divided into four groups: controls, 6-OHDA rats, 6-OHDA + iTBS protocol (two times/day/three weeks) and the sham group. The therapeutic effect of iTBS was evaluated by examining motor coordination, balance, spontaneous forelimb use, exploratory behavior, anxiety-like, depressive/anhedonic-like behavior and short-term memory, histopathological changes and changes at the molecular level. We demonstrated the positive effects of iTBS at both motor and behavioral levels. In addition, the beneficial effects were reflected in reduced degeneration of dopaminergic neurons and a subsequent increase in the level of DA in the caudoputamen. Finally, iTBS altered protein expression and NMDAR subunit composition, suggesting a sustained effect. Applied early in the disease course, the iTBS protocol may be a promising candidate for early-stage PD therapy, affecting motor and nonmotor deficits.

Therapeutic Potential of Low-Intensity Magnetic Field Stimulation in 6-Hydroxydopamine Rat Model of Parkinson’s Disease: From Inflammation to Motor Function

Background and Purpose

Parkinson’s disease (PD) is a progressive neurodegenerative disorder that mainly affects the aged population. Transcranial magnetic field (MF) stimulation has shown to provide temporary motor recovery in neurological disorders. The aim of this study was to understand the cellular and molecular mechanism of low-intensity MF stimulation (17.96 µT; 50Hz; 2 h/day, four weeks) in a rat model of severe PD.

Methods

A clinically relevant, bilateral striatal 6-hydroxydopamine (6-OHDA) lesioned rat model of severe PD was employed to test the efficacy of low-intensity MF stimulation in the management of motor symptoms. The mechanism of action of MF was dissected by assessing the microglial activation, tissue ultrastructure, and cerebrospinal fluid (CSF) metabolomics using microdialysis.

Results

We observed a significant improvement in the postural balance and gait after MF exposure with a significant reduction in the number of activated microglia. There was an improvement in striatal dopaminergic innervation and glutamate levels but it did not reach a level of statistical significance.

Conclusion

MF stimulation helped ameliorate the motor deficits and reduced inflammation but was unable to provide a significant change in terms of dopaminergic innervation and metabolic profile in the severe 6-OHDA PD rat model.

Long-Term Motor Cortical Electrical Stimulation Ameliorates 6-Hydroxydopamine-Induced Motor Dysfunctions and Exerts Neuroprotective Effects in a Rat Model of Parkinson's Disease

OBJECTIVE

Cortical electrical stimulation (CES) can modulate cortical excitability through a plasticity-like mechanism and is considered to have therapeutic potentials in Parkinson's disease (PD). However, the precise therapeutic value of such approach for PD remains unclear. Accordingly, we adopted a PD rat model to determine the therapeutic effects of CES. The current study was thus designed to identify the therapeutic potential of CES in PD rats.

METHODS

A hemiparkinsonian rat model, in which lesions were induced using unilateral injection of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle, was applied to identify the therapeutic effects of long-term (4-week) CES with intermittent theta-burst stimulation (iTBS) protocol (starting 24 h after PD lesion observation, 1 session/day, 5 days/week) on motor function and neuroprotection. After the CES intervention, detailed functional behavioral tests including gait analysis, akinesia, open-field locomotor activity, apomorphine-induced rotation as well as degeneration level of dopaminergic neurons were performed weekly up to postlesion week 4.

RESULTS

After the CES treatment, we found that the 4-week CES intervention ameliorated the motor deficits in gait pattern, akinesia, locomotor activity, and apomorphine-induced rotation. Immunohistochemistry and tyrosine hydroxylase staining analysis demonstrated that the number of dopamine neurons was significantly greater in the CES intervention group than in the sham treatment group.

CONCLUSION

This study suggests that early and long-term CES intervention could reduce the aggravation of motor dysfunction and exert neuroprotective effects in a rat model of PD. Further, this preclinical model of CES may increase the scope for the potential use of CES and serve as a link between animal and PD human studies to further identify the therapeutic mechanism of CES for PD or other neurological disorders.

Moving back in the brain to drive the field forward: Targeting neurostimulation to different brain regions in animal models of depression and neurodegeneration

BACKGROUND

Repetitive transcranial magnetic stimulation is a promising noninvasive therapeutic tool for a variety of brain-related disorders. However, most therapeutic protocols target the anterior regions, leaving many other areas unexplored. There is a substantial therapeutic potential for stimulating various brain regions, which can be optimized in animal models.

NEW METHOD

We illustrate a method that can be utilized reliably to stimulate the anterior or posterior brain in freely moving rodents. A coil support device is surgically attached onto the skull, which is used for consistent coil placement over the course of up to several weeks of stimulation sessions.

RESULTS

Our methods provide reliable stimulation in animals without the need for restraint or sedation. We see little aversive effects of support placement and stimulation. Computational models provide evidence that moving the coil support location can be utilized to target major stimulation sites in humans and mice.

SUMMARY OF FINDINGS WITH THIS METHOD

Animal models are key to optimizing brain stimulation parameters, but research relies on restraint or sedation for consistency in coil placement. The method described here provides a unique means for reliable targeted stimulation in freely moving animals. Research utilizing this method has uncovered changes in biochemical and animal behavioral measurements as a function of brain stimulation.

CONCLUSIONS

The majority of research on magnetic stimulation focuses on anterior regions. Given the substantial network connectivity throughout the brain, it is critical to develop a reliable method for stimulating different regions. The method described here can be utilized to better inform clinical trials about optimal treatment localization, stimulation intensity and number of treatment sessions, and provides a motivation for exploring posterior brain regions for both mice and humans.

Protective effects of repetitive transcranial magnetic stimulation against 6-OHDA-induced Parkinson's symptoms in a mice model: the key role of miR-409-3p/PDHB axis

AIM

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive technique showing improvement effects on Parkinson's disease (PD). Multiple microRNAs (miRs) are dys-expressed during the progression of PD. In the current study, the potential involvement of miRs in the anti-PD effects of rTMS was explored.

METHODS

PD symptoms were induced in mice with 6-OHDA. The expression profile of miRs influenced by rTMS in PD mice was detected by microarray technique and validated by RT-qPCR detection. The PD mice were treated with rTMS and the changes in cognitive behaviors, substantia nigra neuron number, brain histology, and Aβ_1-42 level were detected. The activity of miR-409-3p/PDHB axis was also detected to preliminarily explain the interaction between miRs and rTMS.

RESULTS

The detection of microarray showed that 266 miRs were dys-expressed in PD mice after the administration of rTMS, including 101 up-regulated ones and 146 down-regulated ones. With validation by RT-qPCR detection, miR-409-3p was selected for subsequent assays. Administrations of rTMS improved cognitive behaviors of mice, increased neuron number, and attenuated brain injuries induced by 6-OHDA. The cerebrospinal fluid (CSF) level of Aβ_1-42 was induced, while the brain level of Aβ_1-42 was suppressed by rTMS. Regarding miR-409-3p/PDHB axis, rTMS administrations suppressed miR-409-3p level and increased the expression of PDHB.

CONCLUSION

Administrations of rTMS showed considerable protective effects on brain tissues against PD-induced injuries, which was associated with the changes in miR levels. The current study demonstrated that the inhibition of miR-409-3p by rTMS contributed to the attenuation of PD by inducing PDHB.

Early Repetitive Transcranial Magnetic Stimulation Exerts Neuroprotective Effects and Improves Motor Functions in Hemiparkinsonian Rats

Repetitive transcranial magnetic stimulation (rTMS) is a popular noninvasive technique for modulating motor cortical plasticity and has therapeutic potential for the treatment of Parkinson's disease (PD). However, the therapeutic benefits and related mechanisms of rTMS in PD are still uncertain. Accordingly, preclinical animal research is helpful for enabling translational research to explore an effective therapeutic strategy and for better understanding the underlying mechanisms. Therefore, the current study was designed to identify the therapeutic effects of rTMS on hemiparkinsonian rats. A hemiparkinsonian rat model, induced by unilateral injection of 6-hydroxydopamine (6-OHDA), was applied to evaluate the therapeutic potential of rTMS in motor functions and neuroprotective effect of dopaminergic neurons. Following early and long-term rTMS intervention with an intermittent theta burst stimulation (iTBS) paradigm (starting 24 h post-6-OHDA lesion, 1 session/day, 7 days/week, for a total of 4 weeks) in awake hemiparkinsonian rats, the effects of rTMS on the performance in detailed functional behavioral tests, including video-based gait analysis, the bar test for akinesia, apomorphine-induced rotational analysis, and tests of the degeneration level of dopaminergic neurons, were identified. We found that four weeks of rTMS intervention significantly reduced the aggravation of PD-related symptoms post-6-OHDA lesion. Immunohistochemically, the results showed that tyrosine hydroxylase- (TH-) positive neurons in the substantia nigra pars compacta (SNpc) and fibers in the striatum were significantly preserved in the rTMS treatment group. These findings suggest that early and long-term rTMS with the iTBS paradigm exerts neuroprotective effects and mitigates motor impairments in a hemiparkinsonian rat model. These results further highlight the potential therapeutic effects of rTMS and confirm that long-term rTMS treatment might have clinical relevance and usefulness as an additional treatment approach in individuals with PD.

Clinical and Neurochemical Effects of Transcranial Magnetic Stimulation (TMS) in Multiple Sclerosis: A Study Protocol for a Randomized Clinical Trial

Background: Transcranial Magnetic Stimulation (TMS) is a technique based on the principles of electromagnetic induction. It applies pulses of magnetic radiation that penetrate the brain tissue, and it is a non-invasive, painless, and practically innocuous procedure. Previous studies advocate the therapeutic capacity of TMS in several neurodegenerative and psychiatric processes, both in animal models and in human studies. Its uses in Parkinson's disease, Alzheimer's disease and in Huntington's chorea have shown improvement in the symptomatology and in the molecular profile, and even in the cellular density of the brain. Consequently, the extrapolation of these TMS results in the aforementioned neurodegenerative disease to other entities with etiopathogenic and clinical analogy would raise the relevance and feasibility of its use in multiple sclerosis (MS). The overall objective will be to demonstrate the effectiveness of the TMS in terms of safety and clinical improvement, as well as to observe the molecular changes in relation to the treatment.

Methods and Design: Phase II clinical trial, unicentric, controlled, randomized, single blind. A total of 90 patients diagnosed with relapsing-remitting multiple sclerosis (RRMS) who meet all the inclusion criteria and do not present any of the exclusion criteria that are established and from which clinically evaluable results can be obtained. The patients included will be assigned under the 1:1:1 randomization formula, constituting three groups for the present study: 30 patients treated with natalizumab + white (placebo) + 30 patients treated with natalizumab + TMS (1 Hz) + 30 patients treated with natalizumab + TMS (5 Hz).

Discussion: Results of this study will inform on the efficiency of the TMS for the treatment of MS. The expected results are that TMS is a useful therapeutic resource to improve clinical status (main parameters) and neurochemical profile (surrogate parameters); both types of parameters will be checked.

Ethics and Dissemination: The study is approved by the Local Ethics Committee and registered in https://clinicaltrials.gov (NCT04062331). Dissemination will include submission to a peer-reviewed journal, patients, associations of sick people and family members, healthcare magazines and congress presentations.

Trial Registration:ClinicalTrials.gov ID: NCT04062331 (registration date: 19^th/ August/2019).

Version Identifier: EMTr-EMRR, ver-3, 21/11/2017.

Combination of Human Mesenchymal Stem Cells and Repetitive Transcranial Magnetic Stimulation Enhances Neurological Recovery of 6-Hydroxydopamine Model of Parkinsonian's Disease

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) has been in use for the treatment of various neurological diseases, including depression, anxiety, stroke and Parkinson's disease (PD), while its underlying mechanism is stills unclear. This study was undertaken to evaluate the potential synergism of rTMS treatment to the beneficial effect of human mesenchymal stem cells (hMSCs) administration for PD and to clarify the mechanism of action of this therapeutic approach.

METHODS

The neuroprotective effect in nigral dopamine neurons, neurotrophic/growth factors and anti-/pro-inflammatory cytokine regulation, and functional recovery were assessed in the rat 6-hydroxydopamine (6-OHDA) model of PD upon administration of hMSCs and rTMS.

RESULTS

Transplanted hMSCs were identified in the substantia nigra, and striatum. Enhancement of the survival of SN dopamine neurons and the expression of the tyrosine hydroxylase protein were observed in the hMSCs + rTMS compared to that of controls. Combination therapy significantly elevated the expression of several key neurotrophic factors, of which the highest expression was recorded in the rTMS + hMSC group. In addition, the combination therapy significantly upregulated IL-10 expression while decreased IFN-γ and TNF-α production in a synergistic manner. The treadmill locomotion test (TLT) revealed that motor function was improved in the rTMS + hMSC treatment with synergy.

CONCLUSION

Our findings demonstrate that rTMS treatment and hMSC transplantation could synergistically create a favorable microenvironment for cell survival within the PD rat brain, through alteration of soluble factors such as neurotrophic/growth factors and anti-/pro-inflammatory cytokines related to neuronal protection or repair, with preservation of DA neurons and improvement of motor functions.

Restraint devices for repetitive transcranial magnetic stimulation in mice and rats

INTRODUCTION

Repetitive transcranial magnetic stimulation has been widely used for the treatment of neurological and psychiatric diseases. Rodent animals including mice and rats are often used to investigate the potential cellular and molecular mechanisms for the therapeutic effects of repetitive transcranial magnetic stimulation. So far there is no report about an easy-to-use device to restrain rodent animals for repetitive transcranial magnetic stimulation.

METHODS AND RESULTS

We introduced the design and use of the restraint device for mice or rats. In the mouse device, western blot and real-time PCR analysis showed that，in stimulated mouse frontal cortex, 10 Hz high frequency stimulation for 10 sessions resulted in enhanced expression of NR2B-containing N-methyl-D-aspartic acid receptors and reduced α1 subunit of inhibitory GABA_A receptors, whereas 0.5 Hz low frequency stimulation for 10 sessions caused decreased expression of NR2B subunit and increased α1 subunit of GABA_A receptors. In the rat device, measures of motor evoke potentials indicated that 10 Hz stimulation for 10 sessions increased the excitability of stimulated cortex, whereas 0.5 Hz for 10 sessions reduced it.

CONCLUSIONS

These results suggested the effectiveness of the devices. Thus, the two devices are practical and easy-to-use to investigate the mechanisms of repetitive transcranial magnetic stimulation.

Noninvasive Brain Stimulation to Enhance Functional Recovery After Stroke: Studies in Animal Models

Background. Stroke is the leading cause of adult disability, but treatment options remain limited, leaving most patients with incomplete recovery. Patient and animal studies have shown potential of noninvasive brain stimulation (NIBS) strategies to improve function after stroke. However, mechanisms underlying therapeutic effects of NIBS are unclear and there is no consensus on which NIBS protocols are most effective. Objective. Provide a review of articles that assessed effects and mechanisms of repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) in animal stroke models. Methods. Articles were searched in PubMed, including cross-references. Results. Nineteen eligible studies reporting effects of rTMS or tDCS after stroke in small rodents were identified. Seventeen of those described improved functional recovery or neuroprotection compared with untreated control or sham-stimulated groups. The effects of rTMS could be related to molecular mechanisms associated with ischemic tolerance, neuroprotection, anti-apoptosis, neurogenesis, angiogenesis, or neuroplasticity. Favorable outcome appeared most effectively when using high-frequency (>5 Hz) rTMS or intermittent theta burst stimulation of the ipsilesional hemisphere. tDCS effects were strongly dependent on stimulation polarity and onset time. Although these findings are promising, most studies did not meet Good Laboratory Practice assessment criteria. Conclusions. Despite limited data availability, animal stroke model studies demonstrate potential of NIBS to promote stroke recovery through different working mechanisms. Future studies in animal stroke models should adhere to Good Laboratory Practice guidelines and aim to further develop clinically applicable treatment protocols by identifying most favorable stimulation parameters, treatment onset, adjuvant therapies, and underlying modes of action.

High-Frequency Repetitive Magnetic Stimulation Enhances the Expression of Brain-Derived Neurotrophic Factor Through Activation of Ca2+-Calmodulin-Dependent Protein Kinase II-cAMP-Response Element-Binding Protein Pathway

Repetitive transcranial magnetic stimulation (rTMS) can be used in various neurological disorders. However, neurobiological mechanism of rTMS is not well known. Therefore, in this study, we examined the global gene expression patterns depending on different frequencies of repetitive magnetic stimulation (rMS) in both undifferentiated and differentiated Neuro-2a cells to generate a comprehensive view of the biological mechanisms. The Neuro-2a cells were randomly divided into three groups—the sham (no active stimulation) group, the low-frequency (0.5 Hz stimulation) group, and high-frequency (10 Hz stimulation) group—and were stimulated 10 min for 3 days. The low- and high-frequency groups of rMS on Neuro-2a cells were characterized by transcriptome array. Differentially expressed genes were analyzed using the Database of Annotation Visualization and Integrated Discovery program, which yielded a Kyoto Encyclopedia of Genes and Genomes pathway. Amphetamine addiction pathway, circadian entrainment pathway, long-term potentiation (LTP) pathway, neurotrophin signaling pathway, prolactin signaling pathway, and cholinergic synapse pathway were significantly enriched in high-frequency group compared with low-frequency group. Among these pathways, LTP pathway is relevant to rMS, thus the genes that were involved in LTP pathway were validated by quantitative real-time polymerase chain reaction and western blotting. The expression of glutamate ionotropic receptor N-methyl d-aspartate 1, calmodulin-dependent protein kinase II (CaMKII) δ, and CaMKIIα was increased, and the expression of CaMKIIγ was decreased in high-frequency group. These genes can activate the calcium (Ca²⁺)–CaMKII–cAMP-response element-binding protein (CREB) pathway. Furthermore, high-frequency rMS induced phosphorylation of CREB, brain-derived neurotrophic factor (BDNF) transcription via activation of Ca²⁺–CaMKII–CREB pathway. In conclusion, high-frequency rMS enhances the expression of BDNF by activating Ca²⁺–CaMKII–CREB pathway in the Neuro-2a cells. These findings may help clarify further therapeutic mechanisms of rTMS.

Repetitive transcranial magnetic stimulation (rTMS) improves behavioral and biochemical deficits in levodopa-induced dyskinetic rats model

Fluctuations of dopamine levels and upregulations of NR2B tyrosine phosphorylation in the striatum have been connected with levodopa (L-dopa)-induced dyskinesia (LID) in Parkinson's disease (PD). Repetitive transcranial magnetic stimulation (rTMS) is one of the noninvasive and potential method treating dyskinesia. Yet, the effect of rTMS on the above key pathological events remains unclear. In this study, we gave L-dopa treatment intraperitoneally for 22 days to 6-hydroxydopamine-lesioned PD rats to prepare LID rats model, and subsequently applied rTMS daily for 3 weeks to LID rats model. The effect of rTMS on abnormal involuntary movements (AIMs) was assessed. After ending the experiments, we further determined tyrosine hydroxylase (TH)-positive dopaminergic neurons number by immunohistochemistry, dopamine levels by HPLC, glial cell line-derived neurotrophic factor (GDNF) levels by ELISA, NR2B tyrosine phosphorylation and interactions of NR2B with Fyn by immunoblotting and immunoprecipitation. The results demonstrated that rTMS obviously attenuated AIMs scores, reduced the loss of nigral dopaminergic neurons and the fluctuations of striatal dopamine levels. Meanwhile, rTMS significantly increased the expression of GDNF, which couldrestore the damage of dopaminergic neurons. Additionally, rTMS also reduced the levels of the NR2B tyrosine phosphorylation andits interactions with Fyn in the lesioned striatum of LID rats model. Thus, these data indicate that rTMS can provide benefit for the therapy of LID by improving the key biochemical deficits related to dyskinesia.

Effects of Electroacupuncture on Metabolic Changes in Motor Cortex and Striatum of 6-Hydroxydopamine-Induced Parkinsonian Rats

OBJECTIVE

To explore the possible underlying mechanism by investigating the effect of electroacupuncture (EA) treatment on the primary motor cortex and striatum in a unilateral 6-hydroxydopamine (6-OHDA) induced rat Parkinson's disease (PD) model.

METHODS

Male Sprague-Dawley rats were randomly divided into sham group (n=16), model group (n=14), and EA group (n=14). EA stimulation at Dazhui (GV 14) and Baihui (GV20) was applied to PD rats in the EA group for 4 weeks. Behavioral tests were conducted to evaluate the effectiveness of EA treatment. Metabolites were detected by 7.0 T proton nuclear magnetic resonance.

RESULTS

Following 4 weeks of EA treatment in PD model rats, the abnormal behavioral impairment induced by 6-OHDA was alleviated. In monitoring changes in metabolic activity, ratios of myoinositol/creatine (Cr) and N-acetyl aspartate (NAA)/Cr in the primary motor cortex were significantly lower at the injected side than the non-injected side in PD rats (P=0.024 and 0.020). The ratios of glutamate + glutamine (Glx)/Cr and NAA/Cr in the striatum were higher and lower, respectively, at the injected side than the non-injected side (P=0.046 and 0.008). EA treatment restored the balance of metabolic activity in the primary motor cortex and striatum. In addition, the taurine/Cr ratio and Glx/Cr ratio were elevated in the striatum of PD model rats compared to sham-lesioned rats (P=0.026 and 0.000). EA treatment alleviated the excessive glutamatergic transmission by down-regulating the striatal Glx/Cr ratio (P=0.001). The Glx/Cr ratio was negatively correlated with floor plane spontaneous locomotion in PD rats (P=0.027 and P=0.0007).

CONCLUSIONS

EA treatment is able to normalize the metabolic balance in the primary motor cortex and striatum of PD rats, which may contribute to its therapeutic effect on motor deficits. The striatal Glx/Cr ratio may serve as a potential indicator of PD and a therapeutic target of EA treatment.

Repetitive transcranial magnetic stimulation for treatment of lactacystin-induced Parkinsonian rat model

The dysfunction of ubiquitin-proteasome system is an important pathogenesis in the neurodegenerative process of Parkinson's disease. Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive and potential method in treating Parkinson's disease. To investigate whether rTMS has neuroprotective effects in parkinsonian rat model induced by ubiquitin-proteasome system impairment, we gave rTMS daily for 4 weeks to proteasome inhibitor, lactacystin-induced parkinsonian rat model. Rotational behavior test demonstrated that rTMS obviously reduced apomorphine-induced turning number in parkinsonian rats. rTMS could significantly alleviate the loss of tyrosine hydroxylase-positive dopaminergic neurons in lactacystin-lesioned substantia nigra and prevent the loss of striatal dopamine levels. Furthermore, rTMS also reduced the levels of apoptotic protein (cleaved caspase-3) and inflammatory factors (cyclooxygenase-2 and tumor necrosis factor alpha) in lesioned substantia nigra. These results suggest that rTMS can protect nigral dopaminergic neurons against the ubiquitin-proteasome system impairment-induced degeneration by anti-apoptotic and anti-inflammatory molecular mechanism.

The effect of electroacupuncture on proteomic changes in the motor cortex of 6-OHDA Parkinsonian rats

Electroacupuncture (EA) has been reported to alleviate motor deficits in Parkinson's disease (PD) patients, and PD animal models. However, the mechanisms by which EA improves motor function have not been investigated. We have employed a 6-hydroxydopamine (6-OHDA) unilateral injection induced PD model to investigate whether EA alters protein expression in the motor cortex. We found that 4weeks of EA treatment significantly improved spontaneous floor plane locomotion and rotarod performance. High-throughput proteomic analysis in the motor cortex was employed. The expression of 54 proteins were altered in the unlesioned motor cortex, and 102 protein expressions were altered in the lesioned motor cortex of 6-OHDA rats compared to sham rats. Compared to non-treatment PD control, EA treatment reversed 6 proteins in unlesioned and 19 proteins in lesioned motor cortex. The present study demonstrated that PD induces proteomic changes in the motor cortex, some of which are rescued by EA treatment. These targeted proteins were mainly involved in increasing autophagy, mRNA processing and ATP binding and maintaining the balance of neurotransmitters.

Novel Neuromodulation Techniques to Assess Interhemispheric Communication in Neural Injury and Neurodegenerative Diseases

Interhemispheric interaction has a major role in various neurobehavioral functions. Its disruption is a major contributor to the pathological changes in the setting of brain injury such as traumatic brain injury, peripheral nerve injury, and stroke, as well as neurodegenerative diseases. Because interhemispheric interaction has a crucial role in functional consequence in these neuropathological states, a review of noninvasive and state-of-the-art molecular based neuromodulation methods that focus on or have the potential to elucidate interhemispheric interaction have been performed. This yielded approximately 170 relevant articles on human subjects or animal models. There has been a recent surge of reports on noninvasive methods such as transcranial magnetic stimulation and transcranial direct current stimulation. Since these are noninvasive techniques with little to no side effects, their widespread use in clinical studies can be easily justified. The overview of novel neuromodulation methods and how they can be applied to study the role of interhemispheric communication in neural injury and neurodegenerative disease is provided. Additionally, the potential of each method in therapeutic use as well as investigating the pathophysiology of interhemispheric interaction in neurodegenerative diseases and brain injury is discussed. New technologies such as transcranial magnetic stimulation or transcranial direct current stimulation could have a great impact in understanding interhemispheric pathophysiology associated with acquired injury and neurodegenerative diseases, as well as designing improved rehabilitation therapies. Also, advances in molecular based neuromodulation techniques such as optogenetics and other chemical, thermal, and magnetic based methods provide new capabilities to stimulate or inhibit a specific brain location and a specific neuronal population.

Effects of Intermittent Theta Burst Stimulation on Manual Dexterity and Motor Imagery in Patients with Multiple Sclerosis: A Quasi-Experimental Controlled Study

Background

Intermittent theta burst stimulation (iTBS) is a repetitive transcranial magnetic stimulation (rTMS) protocol that influences cortical excitability and motor function recovery.

Objectives

This study aimed to investigate the effects of iTBS on manual dexterity and hand motor imagery in multiple sclerosis (MS) patients.

Methods

Thirty-six MS patients were non-randomly assigned into sham (control) or iTBS groups. Then, iTBS was delivered to the primary motor cortex for ten days over two consecutive weeks. The patients’ manual dexterity was assessed using the nine-hole peg test (9HPT) and the Box and Block Test (BBT), while the hand motor imagery was assessed with the hand mental rotation task (HMRT).

Results

iTBS group showed a reduction in the time required to complete the 9HPT (mean difference = -3.05, P = 0.002), and an increase in the number of blocks transferred in one minute in the BBT (mean difference = 8.9, P = 0.001) when compared to the control group. Furthermore, there was no significant difference between the two groups in terms of the reaction time (P = 0.761) and response accuracy rate (P = 0.482) in the HMRT.

Conclusions

When iTBS was applied over the primary motor cortex, it significantly improved manual dexterity, but had no significant effect on the hand motor imagery ability in MS patients.

Animal behavioral assessments in current research of Parkinson's disease

Parkinson's disease (PD), a neurodegenerative disorder, is traditionally classified as a movement disorder. Patients typically suffer from many motor dysfunctions. Presently, clinicians and scientists recognize that many non-motor symptoms are associated with PD. There is an increasing interest in both motor and non-motor symptoms in clinical studies on PD patients and laboratory research on animal models that imitate the pathophysiologic features and symptoms of PD patients. Therefore, appropriate behavioral assessments are extremely crucial for correctly understanding the mechanisms of PD and accurately evaluating the efficacy and safety of novel therapies. This article systematically reviews the behavioral assessments, for both motor and non-motor symptoms, in various animal models involved in current PD research. We addressed the strengths and weaknesses of these behavioral tests and their appropriate applications. Moreover, we discussed potential mechanisms behind these behavioral tests and cautioned readers against potential experimental bias. Since most of the behavioral assessments currently used for non-motor symptoms are not particularly designed for animals with PD, it is of the utmost importance to greatly improve experimental design and evaluation in PD research with animal models. Indeed, it is essential to develop specific assessments for non-motor symptoms in PD animals based on their characteristics. We concluded with a prospective view for behavioral assessments with real-time assessment with mobile internet and wearable device in future PD research.

Induction of Neurorestoration From Endogenous Stem Cells

Neural stem cells (NSCs) persist in the subventricular zone lining the ventricles of the adult brain. The resident stem/progenitor cells can be stimulated in vivo by neurotrophic factors, hematopoietic growth factors, magnetic stimulation, and/or physical exercise. In both animals and humans, the differentiation and survival of neurons arising from the subventricular zone may also be regulated by the trophic factors. Since stem/progenitor cells present in the adult brain and the production of new neurons occurs at specific sites, there is a possibility for the treatment of incurable neurological diseases. It might be feasible to induce neurogenesis, which would be particularly efficacious in the treatment of striatal neurodegenerative conditions such as Huntington's disease, as well as cerebrovascular diseases such as ischemic stroke and cerebral palsy, conditions that are widely seen in the clinics. Understanding of the molecular control of endogenous NSC activation and progenitor cell mobilization will likely provide many new opportunities as therapeutic strategies. In this review, we focus on endogenous stem/progenitor cell activation that occurs in response to exogenous factors including neurotrophic factors, hematopoietic growth factors, magnetic stimulation, and an enriched environment. Taken together, these findings suggest the possibility that functional brain repair through induced neurorestoration from endogenous stem cells may soon be a clinical reality.

Effects of low- and high-frequency repetitive magnetic stimulation on neuronal cell proliferation and growth factor expression: A preliminary report

Repetitive magnetic stimulation is a neuropsychiatric and neurorehabilitation tool that can be used to investigate the neurobiology of sensory and motor functions. Few studies have examined the effects of repetitive magnetic stimulation on the modulation of neurotrophic/growth factors and neuronal cells in vitro. Therefore, the current study examined the differential effects of repetitive magnetic stimulation on neuronal cell proliferation as well as various growth factor expression. Immortalized mouse neuroblastoma cells were used as the cell model in this study. Dishes of cultured cells were randomly divided into control, sham, low-frequency (0.5Hz, 1Tesla) and high-frequency (10Hz, 1Tesla) groups (n=4 dishes/group) and were stimulated for 3 days. Expression of neurotrophic/growth factors, Akt and Erk was investigated by Western blotting analysis 3 days after repetitive magnetic stimulation. Neuroblastoma cell proliferation was determined with a cell counting assay. There were differences in cell proliferation based on stimulus frequency. Low-frequency stimulation did not alter proliferation relative to the control, while high-frequency stimulation elevated proliferation relative to the control group. The expression levels of brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), neurotrophin-3 (NT-3) and platelet-derived growth factor (PDGF) were elevated in the high-frequency magnetic stimulation group. Akt and Erk expression was also significantly elevated in the high-frequency stimulation group, while low-frequency stimulation decreased the expression of Akt and Erk compared to the control. In conclusion, we determined that different frequency magnetic stimulation had an influence on neuronal cell proliferation via regulation of Akt and ERK signaling pathways and the expression of growth factors such as BDNF, GDNF, NT-3 and PDGF. These findings represent a promising opportunity to gain insight into how different frequencies of repetitive magnetic stimulation may mediate cell proliferation.

Magnetic Resonance Techniques Applied to the Diagnosis and Treatment of Parkinson's Disease

Parkinson's disease (PD) affects at least 10 million people worldwide. It is a neurodegenerative disease, which is currently diagnosed by neurological examination. No neuroimaging investigation or blood biomarker is available to aid diagnosis and prognosis. Most effort toward diagnosis using magnetic resonance (MR) has been focused on the use of structural/anatomical neuroimaging and diffusion tensor imaging (DTI). However, deep brain stimulation, a current strategy for treating PD, is guided by MR imaging (MRI). For clinical prognosis, diagnosis, and follow-up investigations, blood oxygen level-dependent MRI, DTI, spectroscopy, and transcranial magnetic stimulation have been used. These techniques represent the state of the art in the last 5 years. Here, we focus on MR techniques for the diagnosis and treatment of Parkinson's disease.

Transplanted Neural Stem Cells: Playing a Neuroprotective Role by Ceruloplasmin in the Substantia Nigra of PD Model Rats?

Although mounting evidence suggests that ceruloplasmin (CP) deficiency and iron deposition are pivotal factors responsible for exacerbating demise of dopaminergic neurons in the substantia nigra (SN) of the Parkinsonism and neural stem cells (NSCs) are believed to be excellent candidates for compensating the lost dopaminergic neurons, there are few researches to explore the change of CP expression and of iron deposition in the pathological microenvironment of SN after NSCs transplantation and the ability of grafted NSCs to differentiate directionally into dopaminergic neurons under the changed homeostasis. With substantia nigral stereotaxic technique and NSCs transplantation, we found that tyrosine hydroxylase and CP expression decreased and iron deposition increased in the lesioned SN after 6-OHDA administration compared with control, while tyrosine hydroxylase and CP expression increased and iron deposition decreased after NSCs transplantation compared to 6-OHDA administration alone. Only a small number of embedding NSCs are able to differentiate into dopaminergic neurons. These results suggest that grafted NSCs have an influence on improving the content of CP expression, which may play a neuroprotective role by decreasing iron deposition and ameliorating damage of dopaminergic neurons and possibly underline the iron-related common mechanism of Parkinson's disease and Wilson's disease.

The Neuroprotective Mechanism of Low-Frequency rTMS on Nigral Dopaminergic Neurons of Parkinson's Disease Model Mice

Background. Parkinson's disease is a neurodegenerative disease in elder people, pathophysiologic basis of which is the severe deficiency of dopamine in the striatum. The purpose of the present study was to evaluate the neuroprotective effect of low-frequency rTMS on Parkinson's disease in model mice. Methods. The effects of low-frequency rTMS on the motor function, cortex excitability, neurochemistry, and neurohistopathology of MPTP-induced Parkinson's disease mice were investigated through behavioral detection, electrophysiologic technique, high performance liquid chromatography-electrochemical detection, immunohistochemical staining, and western blot. Results. Low-frequency rTMS could improve the motor coordination impairment of Parkinson's disease mice: the resting motor threshold significantly decreased in the Parkinson's disease mice; the degeneration of nigral dopaminergic neuron and the expression of tyrosine hydroxylase were significantly improved by low-frequency rTMS; moreover, the expressions of brain derived neurotrophic factor and glial cell line derived neurotrophic factor were also improved by low-frequency rTMS. Conclusions. Low-frequency rTMS had a neuroprotective effect on the nigral dopaminergic neuron which might be due to the improved expressions of brain derived neurotrophic factor and glial cell line-derived neurotrophic factor. The present study provided a theoretical basis for the application of low-frequency rTMS in the clinical treatment and recovery of Parkinson's disease.

GDNF-based therapies, GDNF-producing interneurons, and trophic support of the dopaminergic nigrostriatal pathway. Implications for Parkinson's disease

The glial cell line-derived neurotrophic factor (GDNF) is a well-established trophic agent for dopaminergic (DA) neurons in vitro and in vivo. GDNF is necessary for maintenance of neuronal morphological and neurochemical phenotype and protects DA neurons from toxic damage. Numerous studies on animal models of Parkinson’s disease (PD) have reported beneficial effects of GDNF on nigrostriatal DA neuron survival. However, translation of these observations to the clinical setting has been hampered so far by side effects associated with the chronic continuous intra-striatal infusion of recombinant GDNF. In addition, double blind and placebo-controlled clinical trials have not reported any clinically relevant effect of GDNF on PD patients. In the past few years, experiments with conditional Gdnf knockout mice have suggested that GDNF is necessary for maintenance of DA neurons in adulthood. In parallel, new methodologies for exogenous GDNF delivery have been developed. Recently, it has been shown that a small population of scattered, electrically interconnected, parvalbumin positive (PV+) GABAergic interneurons is responsible for most of the GDNF produced in the rodent striatum. In addition, cholinergic striatal interneurons appear to be also involved in the modulation of striatal GDNF. In this review, we summarize current knowledge on brain GDNF delivery, homeostasis, and its effects on nigrostriatal DA neurons. Special attention is paid to the therapeutic potential of endogenous GDNF stimulation in PD.

Potential therapeutic effects of neurotrophins for acute and chronic neurological diseases

The neurotrophins (NTs) nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), NT-3, and NT-4/5 are proteins that regulate cell proliferation, differentiation, and survival in both the developing and mature central nervous system (CNS) by binding to two receptor classes, Trk receptors and p75 NTR. Motivated by the broad growth- and survival-promoting effects of these proteins, numerous studies have attempted to use exogenous NTs to prevent the death of cells that are associated with neurological disease or promote the regeneration of severed axons caused by mechanical injury. Indeed, such neurotrophic effects have been repeatedly demonstrated in animal models of stroke, nerve injury, and neurodegenerative disease. However, limitations, including the short biological half-lives and poor blood-brain permeability of these proteins, prevent routine application from treating human disease. In this report, we reviewed evidence for the neuroprotective efficacy of NTs in animal models, highlighting outstanding technical challenges and discussing more recent attempts to harness the neuroprotective capacity of endogenous NTs using small molecule inducers and cell transplantation.

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.