1-甲基-4-苯基-1,2,3,6-四氫吡啶引發臺灣葉鼻蝠腦組織的神經損傷

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2019

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帕金森氏症 (Parkinson’s disease)是一種影響運動的神經退行性疾病,臨床表現包括顫抖、肌肉僵直以及步態遲緩,病理特徵是中腦黑質組織內多巴胺神經細胞的退化及死亡。過去帕金森氏症動物模式常採用腹腔注射1-甲基-4-苯基-1,2,3,6-四氫吡啶 (MPTP),導致帕金森氏症疾病模式。MPTP是一種親脂性的原毒素,以腹腔注射後即迅速穿過血腦屏障。一旦進入大腦,MPTP被星形膠質細胞攝取並通過單胺氧化酶-B (MAO-B)轉化為中間體1-甲基-4-苯基-2,3-二氫吡啶鎓 (MPDP)。然後再通過紋狀體神經元多巴胺D1接受器的蛋白將MPDP傳入紋狀體神經元。多巴胺神經元中的細胞質MPP抑制線粒體電子傳遞鏈的複合物I +然後將+快速且自發地氧化成毒性部分1-甲基-4-苯基吡啶鎓 (MPP + ; Chiba,Trevor,&Castagnoli,1984)。之後,MPP + +並導致ATP耗盡和氧化應激增加。出於這個原因,MPP +還選擇性地殺死多巴胺神經元 (Oxidative Stress and Neurodegenerative Disorders, 2007)。本論文選擇臺灣葉鼻蝠作為動物模式,腹腔連續注射MPTP一週後,利用免疫組織化學與西方墨點法分析蝙蝠中腦黑質與大腦基底核周邊的神經組織,檢視是否有類似帕金森氏症的表現。實驗結果顯示,中腦黑質神經細胞內合成多巴胺的相關酵素-芳香族L-胺基酸脫羧酶(AADC)表達減少;而且黑質神經細胞內發炎作用相關蛋白腫瘤壞死因子-α (TNF-α)、氧化壓力相關蛋白-3-硝基酪氨酸 (3-NT)及細胞凋亡相關蛋白-細胞淋巴瘤聯結X蛋白(BAX)、半胱天冬酶原3 (Caspase 3)表達增強;而黑質神經細胞內抗氧化壓力相關蛋白-超氧化物歧化酶 2 (SOD 2)與抗細胞凋亡相關蛋白-細胞淋巴瘤蛋白-2 (Bcl-2)表達降低;此外,基底核內紋狀體神經細胞多巴胺D1接受器蛋白表達減少。綜合上述研究結果,本論文實驗初步證實MPTP處理的回聲定位,蝙蝠確實會因為MPTP誘發黑質神經細胞產生發炎反應、氧化壓力、以及細胞凋亡,進而導致腦內黑質神經細胞損傷。由於MPTP實驗處理會使得回聲定位蝙蝠產生運動失調,此現象類似帕金森氏症病徵,這結果說明利用MPTP處理回聲定位蝙蝠的動物模式,未來應該可以作為探討帕金森氏症相關研究的新穎實驗動物平台。
Parkinson’s disease is a neurodegenerative disease that affects exercise. Clinical manifestations include tremors, muscle stiffness, and gait retardation. Pathological features are degeneration and death of dopaminergic neurons in the substantia nigra tissue. In the past, most animal models of Parkinson's disease were injected with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a neurotoxin that affects the electron transport chain of granulocytes and then makes dopamine cells die. MPTP is a lipophilic protoxin that rapidly crosses the blood-brain barrier after intraperitoneal injection. Once in the brain, MPTP is taken up by astrocytes and converted to the intermediate 1-methyl-4-phenyl-2,3-dihydropyridinium (MPDP) by monoamine oxidase-B (MAO-B). MPDP is then introduced into the striatum neurons through the protein of the striatal neuron dopamine D1 receptor. Cytoplasmic MPP in dopamine neurons inhibits the mitochondrial electron transport chain complex I + and then rapidly + spontaneously oxidizes to the toxic moiety 1-methyl-4-phenylpyridinium (MPP + ; Chiba, Trevor,& Castagnoli, 1984 ). After that, MPP + + causes an increase in ATP depletion and oxidative stress. For this reason, MPP + also selectively kills dopamine neurons (Oxidative Stress and Neurodegenerative Disorders, 2007). In this thesis, an echolocation bat, Hipposideros armiger terasensis was selected as an animal model. After a week of continuous intraperitoneal injection of MPTP, we used immunochemistry and molecular biological technology to examine whether the substantia nigra and basal ganglia would be similar to other Parkinson's animal models. Our results showed that dopamine synthesis-related Aromatic L-amino acid decarboxylase (AADC) expressions in the substantia nigra were decreased, and those related protein expressions of inflammation-related Tumor Necrosis Factor-α (TNF-α), oxidative stress-related 3-Nitrotyrosine (3-NT), and apoptosis-related Bcl-2- Associated X (BAX) and Caspase 3 in the substantia nigra were increased, while those related protein expressions of anti-oxidative stress-related superoxide dismutase 2 (SOD2) and anti-apoptosis-related B-cell lymphoma 2 (Bcl-2) were decreased. In addition, dopamine D1 receptor protein expressions were decreased in the striatum. Based on our findings, the experiments in our thesis preliminary confirmed that the MPTP-treated echolocation bat may cause damage to the substantia nigra neurons in the brain due to the inflammation, oxidative stress, and apoptosis. Echolocation bats with MPTP treatment show ataxia that is similar to Parkinson's disease . Thus we suggested that MPTP-treated echolocation bats can be a novel experimental animal model to explore Parkinson's disease in the future.

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帕金森氏症, 1-甲基-4-苯基-1, 2, 3, 6-四氫-吡啶, 發炎作用, 氧化壓力, 細胞凋亡, 黑質, 紋狀體, 回聲定位蝙蝠, Parkinson’s disease, MPTP, inflammation, oxidative stress, apoptosis, substantia nigra, striatum, echolocation bats

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