2012-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/701557摘要：許多研究指出營養可能是阿茲海默症的重要致病因素；例如血中葉酸濃度較低者常有大腦萎縮的現象、及發生阿茲海默症的情形。在我們早期以類澱粉先驅蛋白(APP) 轉植基因鼠(Tg2576)所作的實驗發現，轉植鼠接受葉酸與 memantine 合併治療後，在 空間記憶與神經細胞的保護功能上，優於只接受 memantine、或未治療組；進一步以微 陣列(microarray)分析，合併治療組相對於單一 memantine 治療組，在神經生成、發 展、分化，記憶與神經傳導物質受體的相關基因表現上有提升的作用。在我們另外一 個動物實驗中也顯示，飲食中葉酸缺乏會造成腦中不同區域的葉酸濃度下降、與增加 脂肪過氧化及粒線體 DNA4834 缺失，特別在海馬迴部位；而飲食中的葉酸補充，可以 減少因在腦室注射乙型類澱粉蛋白(Aβ)所引發類似的脂肪過氧化、粒線體 DNA 病變與 神經細胞死亡。另一個以類澱粉先驅蛋白轉植細胞株所作的實驗也顯示，葉酸比之於 memantine 在乙型類澱粉蛋白引發的凋零或破壞死亡、與基因調控有相同或更好的保護 效果。3xTg-AD 是將兩種與阿茲海默症相關的變異基因(APPSWE and TauP301L)注入同型 結合(homozygous)的 PS1M146V 胚胎細胞所形成的轉植基因鼠。牠們可以表現出阿茲海 默症隨著年齡增加而出現的老斑(amyloid plaques)與神經纖維節結(neurofibrillary tangle)兩種典型病理變化，以及與病理變化相符的行為功能改變。利用這個較佳的阿 茲海默症動物模式，我們希望進一步確認上述葉酸補充所造成神經細胞保護、基因表 現調控，與乙型類澱粉及 tau 蛋白生成影響。這是一個探討葉酸在神經系統除了傳統 熟悉的單炭代謝(one-carbon metabolism)外的作用機轉的研究；此外我們也引進最新 的類澱粉正子攝影(Amyloid PET)在活體狀態測量腦中類澱粉蛋白含量，作為效果評估 的工具。在第一年計畫的前期工作中，我們團隊已由國家動物中心分批引進 3xTg-AD 轉植基因鼠，分成老年(12 月齡)及年輕(6 月齡)組別，依序完成穩定飼育與初期的水 迷宮測試，並著手進行葉酸餵食試驗及後續第二、三年之分析工作。<br> Abstract: There is evidence that some diet factor play a role in the pathogenesis of Alzheimer’s disease (AD). Low serum folic acid levels are strongly associated with cerebral cortex atrophy, and also increase risk in the developing of AD. In our pervious study, the APP transgenic mice (Tg2576) received memantine and folic acid showed significant group effects on spatial learning, and neuronal protection as compared to both memantine treatment only and non-treatment transgenic controls. In further analysis of global gene expression with microarray, folic acid supplement plus memantine group showed generalized up-regulation of brain gene transcriptions involving in neurogenesis, neuron development or differentiation-associated transcription factors, memory and neurotransmitter receptors as compared to memantine-treated group. In our another animal experiment revealed that folic acid deprivation differentially depleted brain folic acid levels, and increased lipid peroxidation and mtDNA4834 deletions, particularly, in the hippocampus. Upon Aβ challenge, the folate-supplment diet protects various brain regions against lipid peroxidation, mitochondrial genotoxicity and neural death associated with folic acid deprivation. In a pilot study designed as APP transfected cell line with folic acid only or with memantine, we also found that folic acid alone has the same or even better effect to relieve the apoptotic and necrotic effect, and even gene regulation induced by Aβ.3xTg-AD mice are generated from simultaneously microinjecting two transgenes (i.e., APPSWE and TauP301L) into single-cell embryos from homozygous PS1M146v knock-in mice. They develop two age-related neuropathological features associated with AD, amyloid plaques and neurofibrillary tangle formation, as well as age-related behavioral deficits that correlate with the neuropathology. Using this new model, we want to clarify the exact influence of folic acid supplement to the production or degradation of Aβ and hyperphosphorylated tau, neuronal survival, and up-regulation expression of certain genes which we found before in the nervous system, and their inter-relationship in degenerative process of Alzheimer’s disease. It is an investigation to study the novel mechanism of folic acid, except one-carbon metabolism, in the nervous system. In addition, amyloid PET is a new-developed tool for quantitative analysis of amyloid loading in vivo, and will be also utilized in this study to evaluate the therapeutic effect. In the first year project, we have got the transgenic mice from the National laboratory animal center and finished the initial prepare work, including the water maze test. Mice are also divided into 2 major groups of older (12m/o) and younger age (6 m/o). Experiment with folic feeding is under progress, andthen the further analysis in the coming 2nd and 3rd year’s program.阿茲海默症葉酸3xTg-AD類澱粉正子攝影Alzheimer’s diseaseFolic acid3xTg-ADAmyloid PET