天麻水萃物對皮質固酮誘導PC12細胞損傷之神經保護功效

Neuroprotective effect of water extract of Gastrodia elata Bl. on the corticosterone-induced lesion in rat adrenal pheochromocytoma PC12 cells

林惠瑩(Huei-Ying Lin)

指導教授 ： 沈立言

國立臺灣大學/生物資源暨農學院/食品科技研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.03425

摘要

根據行政院衛生署公告之死因統計，歷年(1987~2008年)來自殺之死亡人數有逐年攀升之趨勢，而世界衛生組織也指出，自殺的人當中高達80-100%的人有精神疾病，又以憂鬱症患者居多。已有研究指出憂鬱症的患者多有hypothalamic-pituitary-adrenal axis (HPA axis)過度活化的情形，進而會引起醣皮質固醇(glucocorticoids，如皮質固酮corticosterone, Cort)過度分泌與興奮性胺基酸(excitatory amino acid, EAA，如glutamate)之積聚，結果造成鈣離子通道過度被活化而致使細胞內鈣離子濃度過高，若大量的鈣離子積聚於粒線體內，粒線體膜通透性會因此發生改變，促細胞凋亡因子尌被釋出至細胞質，最終誘使神經細胞走向細胞凋亡，而這些神經細胞的減少可能與憂鬱症有關。天麻為傳統中藥材，已有研究指出天麻具有抗抽搐、抗氧化等生理活性。本實驗室之前的研究也證實天麻水萃物(water extract of Gastrodia elata Bl., WEGE)具有抗憂鬱功效，其對老鼠腻中單胺類神經傳導物質的調節為其可能機制之一。因此，本研究之目的乃藉由Cort誘導rat adrenal pheochromocytoma PC12細胞損傷之神經毒性(neurotoxicity)，探討WEGE與可能活性成分對Cort所造成PC12細胞損傷之保護作用，於細胞模式中瞭解WEGE抗憂鬱之可能作用機制。研究結果顯示，4-hydroxybenzyl alcohol (HBA)可能為WEGE抗憂鬱活性成分之一。WEGE與HBA皆能顯著抑制由Cort誘導所造成PC12細胞存活率之下降，sub-G1期比例之增加，細胞內鈣離子濃度之上升，以及caspase-3的活性之增加。此外，WEGE和HBA亦會調節細胞凋亡相關蛋白質之表現，包括抑制由Cort誘導所造成之促凋亡Bax蛋白質表現量之增加、抑凋亡Bcl-2蛋白質表現量之減少，以及pro-caspase-9蛋白質表現量之減少和裂解態PARP蛋白質表現量之增加。由上述結果得知WEGE與HBA可保護PC12細胞免於Cort引起細胞內鈣離子濃度增加所造成之細胞凋亡，故推測天麻水萃物之抗憂鬱能力可能與減少憂鬱症相關神經元細胞的損傷有關。

關鍵字

憂鬱症 ； 天麻 ； 皮質固酮 ； PC12細胞 ； 鈣離子 ； 細胞凋亡

並列摘要

According to the report of department of Health, Executive Yuan, the event of suicide-caused death is getting more from 1987 to 2008. WHO reported that 80-100% of suicided people are the patients with mental disorder, especially depression. Most patients with depression had the hyperactivity of hypothalamic-pituitary-adrenal axis (HPA axis) which induces over-excretion of glucocorticoids such as corticosterone (Cort) and accumulation of excitatory amino acids (EAA) such as glutamate, and then results in high activation of calcium channel and overloading of intracellular calcium. Accumulated calcium ions in mitochondrial change mitochondrial membrane permeability and release apoptosis-related factors to cytosol to induce cell death via apoptosis. The loss of neuron cells is related to depression. Gastrodia elata Bl., a traditional Chinese medicine, exhibits lots of bioactivities, including anticonvulsion, antioxidation, etc. Our previous study demonstrated that water extract of Gastrodia elata Bl. (WEGE) has an antidepressive effect and an ability to modulate the amounts of monoamines in the rat brain. In the present study, neuroprotective effect of WEGE and possible active compounds on the Cort-induced lesion in PC12 cells was investigated to understand the antidepression mechanism of WEGE. The result of HPLC analysis indicated that 4-hydroxybenzyl alcohol (HBA) might be one of the potential active compounds with antidepressive ability in WEGE. Both of WEGE and HBA inhibited the Cort-induced decrease of cell viability and increase of percentage of sub-G1, concentration of intracellular calcium, and activity of caspase-3. Additionally, WEGE and HBA inhibited the Cort-induced increase of pro-apoptotic Bax and cleaved PARP protein expression, while they also maintained the decrease of anti-apoptotic Bcl-2 and pro-caspase-9 protein expression those caused by Cort in PC12 cells. Therefore, WEGE and HBA protected PC12 cells from the cort-induced apoptosis accompanied with increased the intracellular calcium concentration, and it suggested that one of the
depression mechanism of WEGE is to decrease the loss of neuron cells.

並列關鍵字

depression ； Gastrodia elata Bl. ； corticosterone ； PC12 cells ； calcium ； apoptosis

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