比較中西抗老化藥材在神經退化性疾病之療效─抗氧化功能探討

莊季瑛
國立成功大
本實驗將利用神經毒物MPP+能專一性破壞多巴胺神經細胞﹐直接注射至大鼠的紋狀體﹐模擬巴金森氏症的動物模式﹐探討並比較中藥─茯苓﹑桑白皮﹑防己﹑枸杞子和西藥─褪黑激素等抗老化藥材﹐是否具有治療此神經老化退化性疾病的功效。許多文獻證實：腦中大量自由基的產生和抗氧化功能的降低﹐是常見的神經老化退化性疾病─如：巴金森氏症及阿采默氏症的重要致病機轉。實驗證據也指出：由多巴胺神經細胞末稍所在處,紋狀體,注射MPP+﹐會逆行至多巴胺神經細胞體所在處─中腦的黑質區﹐藉由其抑制粒腺體電子傳遞鏈的complex I酵素的活性﹐產生大量自由基並降低細胞內抗氧化防禦系統的活性﹐進而導致毒殺多巴胺神經細胞和紋狀體的神經細胞。我們已前的實驗結果指出（見圖一）：MPP+注射至紋狀體﹐會顯著降低還原態麩胺基硫 (GSH)含量及麩胺基硫過氧化西每(GSH peroxidase)活性﹐但提高氧化態麩胺基硫／還原態麩胺基硫(GSSG/GSH)含量比值﹐進而導致紋狀體神經細胞及黑質區多巴胺細胞的大量死亡﹐若給予西藥抗老化藥劑褪黑激素則能有效顯著避免上述MPP+所誘發的神經毒性。有鑑於此﹐我們想利用此模式探討並比較中藥抗老化藥材─茯苓﹑桑白皮﹑防己﹑枸杞子與褪黑激素對神經老化退化性疾病─巴金森氏症的療效為何。特別挑選這些中藥一是為民間常用抗老化藥材﹐二是這些中藥已被文獻指出具有和褪黑激素相同的抗氧化作用之特性﹐是否藉此作用來達到保護細胞免於因自由基攻擊的神經老化退化性疾病。實驗將分為對照組及藥物處理組﹐對照組為單側直接注射100 nmole/ 1μl 的MPP+至紋狀體加上由腹腔注射溶劑﹐藥物處理組為單側紋狀體注射MPP+再加上腹腔注射各種藥材─茯苓或桑白皮或防己或枸杞子或褪黑激素﹐三天後﹐將大白鼠斷頭犧牲取出兩側的紋狀體及中腦黑質區（一側為對照區另一側為MPP+破壞區）﹐進行GSH, GSSG含量測定, GSH peroxidase活性測定及脂質過氧化測量﹐另一部份大白鼠則予以灌流固定包埋﹐進行Nissl及TUNEL stain﹐觀察與比較大腦兩側：對照側 (contralateral)和MPP+注射側的紋狀體及黑質區神經細胞損傷情形﹐並以免疫化學法染含有tyrosin hydroxylase (TH, 一種合成多巴胺的重要酵素) 的神經細胞﹐觀察並量化多巴胺神經細胞在中腦黑質區流失情形。藉這些參數評估茯苓或桑白皮或防己或枸杞子或褪黑激素等藥材﹐是否具有避免MPP+所誘發的上述毒性及其療效程度差異性如何。完成本實驗後﹐我們將可提供抗老化中藥的抗老化藥理機轉的科學證據﹐並指出中西抗老化藥材其藥效的異同。
關鍵字：茯苓;桑白皮;防己;枸杞子;褪黑激素;抗氧化功能;麩胺基硫; MPP+

A comparative study in the protective effect of Chinese and western anti-aging medicine in MPP+-induced neurodegeneration

Jih-Ing Chuang
Department of Physiology, College of Medicine, National Cheng Kung University
The protective effecacy of anti-aging medicine, such as Poria, Lycii Fructus, Fangji Radix, Mori Radicis Cortex and melatonin, will be investigated in MPP+-induced neurotoxicity. The formation of hydroxyl free radical and reduced level of the endogenous antioxidant glutathione (GSH) have been implicated in aging process and in age-related neurodegenerative diseases, as well as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced parkinsonism. Indeed, our previous results had demonstrated that infusion of MPP+ (a neurotoxic metabolite of MPTP formed by MAO-B) to striatum causes oxidative stress (including the decrease of GSH, the increase of GSSG (oxidized form of glutathione)/GSH ratio) in injected site of striatum and ipsilateral retrograde area of substantial nigra, thereby results in dopaminergic neuronal loss in substantial nigra. Interestingly, co-treatment with melatonin, a pineal hormone known as an antioxidant and anti-aging molecule, significantly attenuated the dysfunc
關鍵字：Poria; Lycii Fructus; Fangji Radix; Mori Radicis Cortex; melatonin; antioxidation; glutathione; MPP+