在疾病大鼠模型中探討皮質電刺激對於腦外傷和帕金森氏症之治療效益

Identification of therapeutic effects of cortical electrical stimulation in the rat model of traumatic brain injury and Parkinson's disease

郭紀偉(Chi-Wei Kuo)

指導教授 ： 潘建源

國立臺灣大學/生命科學院/生命科學系/博士(2021年)

https://doi.org/10.6342/NTU202101504

摘要

大腦為處理感覺、動作、記憶、學習、情緒及其他行為的核心，當大腦受到外力性傷害或內因性疾病時，神經元因損傷而改變其活性，在未受到妥善的治療下，除影響生理機能外，嚴重者將走向神經退化的威脅。過去許多大腦刺激技術，例如應用於實驗神經科學的皮質電刺激 (cortical electrical stimulation, CES) 已經被發展來調控神經塑性，這個效果被認為具有治療神經相關疾病之潛力。
　　創傷性腦損傷 (traumatic brain injury, TBI) 患者會根據嚴重程度，在運動、感覺、神經性及認知上有長期性障礙，迄今為止，尚未有治療方式是以神經調節來治療TBI所引起的功能損傷。帕金森氏症 (Parkinson's disease, PD) 是普遍的神經退行性疾病之一，其病理特徵為位於黑質緻密部的多巴胺神經元退化而成，伴隨多種動作障礙。由於CES已發展成透過可塑性機制進而調節皮質抑制或興奮性，被認為此具有治療大腦損傷或神經退化性疾病的潛力。然而，這種技術對於TBI與PD的治療價值尚不清楚。因此，本文利用疾病動物模型來闡明CES的可能治療效果。
　　在本研究動物實驗中，陣發型波段刺激 (theta burst stimulation, TBS) 被設定為皮質電刺激的參數，TBS的特性為以短時間的刺激達到較長之影響。TBS的模式可以連續型TBS (continuous theta burst stimulation, cTBS) 及間歇型TBS (intermittent theta burst stimulation iTBS) 方式輸出。其中cTBS會降低動作誘發電位 (motor evoked potentials, MEPs) 的振幅，產生類似於長期抑制作用 (long-term depression, LTD) 塑性的效果，iTBS會增加MEPs的振幅，產生類似於長期增強作用 (long-term potentiation, LTP) 神經塑性的效果。
　　對於 CES 的刺激模式，我們採用了一種常用且特定的陣發型脈衝刺激(theta burst stimulation, TBS) 做為CES的刺激參數，TBS的特性為以短時間與較低強度的刺激達到較長之影響。TBS的模式可以連續型TBS (continuous theta burst stimulation, cTBS) 及間歇型TBS (intermittent theta burst stimulation iTBS) 方式輸出。過去此兩種模式已被發現可誘發長期增強作用 (Long-term potentiation, LTP) 神經塑性或是產生類似於長期抑制作用 (Long-term depression, LTD) 塑性的效果的效果。根據cTBS和iTBS的不同影響效果，在本研究應用在以外因性為例的TBI動物模型中，在不同發炎階段下使用cTBS及iTBS治療。此外，本實驗亦使用內因性疾病為例的PD的模型中使用iTBS治療，來改善疾病所產生的症狀。　　
　　在TBI大鼠模型中，探討早期和長期CES-TBS治療四周後，以神經學損傷分數評估 (modified neurological severity score, mNSS) 鑑定CES-TBS治療對感覺、運動、認知、行為和神經性發炎變化的影響。在6-OHDA帕金森大鼠模型中，探討在長期CES-iTBS治療後，以步態、橫桿試驗、開放空間試驗、阿朴嗎啡誘導的旋轉分析以及多巴胺衰退水平的試驗，以評估CES-iTBS在運動功能中的治療效果。本研究結果顯示為期四周的CES-TBS治療顯著減輕了TBI在神經系統、感覺運動和認知方面所引起的活動力、感覺和識別記憶缺陷。在免疫組織化學方面，我們發現CES-TBS減緩了海馬迴中膠質纖維酸性蛋白 (glial fibrillary acidic protein, GFAP) 的活化。然而在CES-iTBS治療後6-OHDA帕金森大鼠模型，發現4週的CES-iTBS治療在步態模式、運動失能、活動力和阿朴嗎啡誘導的旋轉分析中獲得改善。在免疫組織化學，酪氨酸羥化酶 (tyrosine hydroxylase, TH) 染色分析顯示，多巴胺神經元顯著保存。在西方墨點法獲得相同的結果。
　　這些發現顯示CES-TBS在減輕TBI相關症狀方面具有顯著的幫助，有希望成為TBI的治療方法。另外，我們發現CES-iTBS在6-OHDA帕金森大鼠模型中可改善運動及保留多巴胺神經元的效果。
　　此CES-TBS技術或許可以加強皮質電刺激治療對TBI與PD之未來治療之可行性以及提供一個人類與動物研究之轉譯橋樑，進而發展對於TBI與PD之治療策略。未來的臨床前研究仍需要進一步定義CES-TBS之潛在治療機制，從而改進 TBI或PD的CES-TBS效益。

關鍵字

皮質電刺激 ； 陣發型波段刺激 ； 創傷性腦損傷 ； 帕金森氏症 ； 神經調節 ； 認知行為障礙 ； 運動障礙

並列摘要

The brain is the core of sensory, motor, memory, learning, emotional and other behaviors. When the brain is damaged by external forces or endogenous diseases, the neuronal activity is altered due to the damage, and without proper treatment, it will not only affect the physiological function, but also threaten to neurodegeneration in serious cases. Various brain stimulation techniques such as cortical electrical stimulation (CES), has been increasingly developed for modulating neural plasticity which are considered having therapeutic potentials in neurological disorders.
　　Individuals with traumatic brain injury (TBI) often suffer long-lasting motor, sensory, neurological or cognitive disturbances. To date, no neuromodulation-based therapies have been used to manage the functional deficits associated with TBI. Parkinson’s disease (PD) is one of the prevalent neurodegenerative disorder. The pathologic hallmark of the disease results from degeneration of the dopaminergic neurons (DA) in the substantia nigra (SN), several motor disturbances. CES has been developed for modulating cortical inhibition or excitability via plasticity-like mechanism and is considered having therapeutic potentials in brain injury or neurodegenerative diseases. However, the therapeutic value of such approach for brain injury or neurodegenerative diseases is still unclear. Accordingly, we adopted the rat model for elucidating the possible therapeutic effects of CES.
　　For the stimulation protocol of CES, we applied a specific and popular paradigm, the continue theta burst stimulation (cTBS) or intermittent theta burst stimulation (iTBS) protocol, have been proposed for inducing more efficient long-term potentiation (LTP) or long-term depression (LTD)-like plasticity in the cortex beyond the short period of stimulation and lower intensity. In this study, cTBS and iTBS was applied in a model of traumatic brain injury, as in the case of external forces, at different phase of inflammation, and in a model of Parkinson's disease, as in the case of endogenous disease, to improve the symptoms produced by the disease.
　　In the rat model of TBI, following early and long-term CES-TBS intervention for a total of 28 days, the effects of CES-TBS on the modified neurological severity score (mNSS), sensorimotor, cognitive, behaviors and neuroinflammatory changes were identified. In the 6-OHDA rat model of PD was applied to investigate the therapeutic roles of CES-TBS in motor functions following long-term CES-iTBS treatment for 4 weeks. After CES-iTBS intervention, the detailed functional behavioral tests and DA degeneration level were assessed up to 4 weeks. The results show that the 4-week CES-TBS intervention significantly alleviated the TBI-induced neurological, sensorimotor and cognitive deficits in locomotor activity, sensory and recognition memory. Immunohistochemically, we found that CES-TBS mitigated the glial fibrillary acidic protein (GFAP) activation in the hippocampus. Then 6-OHDA rat model of PD after CES-iTBS treatment, we found that 4 weeks of CES-iTBS intervention ameliorates the motor deficits in behavioral tests. Immunohistochemistry, tyrosine hydroxylase (TH) staining analysis demonstrated that the dopamine neurons were significantly preserved. Similar results were obtained in western blot.
　　These findings suggest that CES-TBS has significant benefits in alleviating TBI-related symptoms and represents a promising treatment for TBI. In addition, the efficacy of CES-iTBS improved motor and dopaminergic retention in 6-OHDA rat model of PD.
This CES-TBS approach may enhance for promising possibility of potential use of CES and may serve as a translational platform bridging human and animal studies for developing therapeutic strategies of CES-TBS for TBI or PD. Future preclinical studies are still needed to further define the underlying mechanisms, leading to improved CES-TBS protocols for TBI.

並列關鍵字

Cortical electrical stimulation (CES) ； Theta burst stimulation (TBS) ； Traumatic brain injury (TBI) ； Parkinson's disease(PD) ； Neuromodulation ； Cognitive deficits ； Motor deficits

參考文獻

1. Speelman, J.D.; Bosch, D.A. Resurgence of functional neurosurgery for Parkinson's disease: a historical perspective. Mov Disord 1998, 13, 582-588, doi:10.1002/mds.870130336.

2. Fregni, F.; Boggio, P.S.; Nitsche, M.; Bermpohl, F.; Antal, A.; Feredoes, E.; Marcolin, M.A.; Rigonatti, S.P.; Silva, M.T.; Paulus, W., et al. Anodal transcranial direct current stimulation of prefrontal cortex enhances working memory. Exp Brain Res 2005, 166, 23-30, doi:10.1007/s00221-005-2334-6.

3. Inman, C.S.; Manns, J.R.; Bijanki, K.R.; Bass, D.I.; Hamann, S.; Drane, D.L.; Fasano, R.E.; Kovach, C.K.; Gross, R.E.; Willie, J.T. Direct electrical stimulation of the amygdala enhances declarative memory in humans. Proc Natl Acad Sci U S A 2018, 115, 98-103, doi:10.1073/pnas.1714058114.

4. Nitsche, M.A.; Schauenburg, A.; Lang, N.; Liebetanz, D.; Exner, C.; Paulus, W.; Tergau, F. Facilitation of implicit motor learning by weak transcranial direct current stimulation of the primary motor cortex in the human. J Cogn Neurosci 2003, 15, 619-626, doi:10.1162/089892903321662994.

5. Butefisch, C.M.; Khurana, V.; Kopylev, L.; Cohen, L.G. Enhancing encoding of a motor memory in the primary motor cortex by cortical stimulation. J Neurophysiol 2004, 91, 2110-2116, doi:10.1152/jn.01038.2003.