利用體外及體內研究方式探討維生素E衍生物2,2,5,7,8-methyl-6-hydroxychromane對血管平滑肌 細胞增生之抑制作用

Inhibition of vascular smooth muscle cell proliferation of vitamin E derivative 2,2,5,7,8-methyl-6-hydroxychromane in an in vitro and in vivo study

謝政穎(Cheng-Ying Hsieh)

指導教授 ： 許準榕

共同指導教授 ： 蕭哲志

臺北醫學大學/醫學院/醫學科學研究所/博士(2010年)

https://doi.org/10.6831/TMU.2010.00108

摘要

在過去的研究已發現異常增生的血管平滑肌細胞在心血管疾病的病程進行中扮演了重要的角色。本篇論文將探討PMC（2,2,5,7,8-methyl-6-hydroxychromane），這個強效的維生素 E衍生物對血管內膜不正常增生的影響，及深入研究PMC抑制血小板衍生生長因子(PDGF-BB)引發血管平滑肌細胞增生的分子機轉。
實驗結果發現PMC（20和50 ?嵱）明顯抑制PDGF-BB引發的血管平滑肌細胞增生且使細胞週期停止在G2/M期，但並不影響正常狀態下的血管平滑肌細胞。在動物實驗中亦發現PMC (5 mg/kg/day)可顯著減少氣球擴張術所引發之血管內膜增生。在分子機轉探討的實驗中發現，PMC可有效的抑制PDGF-BB引發之STAT3、JAK2、PLCγ1、PKC的活化及ROS的產生，但不影響ERK1 / 2、AKT、或PKC?悛漯穛{。此外，鐵離子螯合劑deferoxamine和PMC一樣，可有效抑制PLCγ1和JAK2的磷酸化，並使細胞週期停滯在G2/M期，而這些抑制效果在給予Fe2 +時會被消除掉。此外，利用電子自旋共振儀偵測，發現PMC可清除Fenton反應和PDGF-BB刺激血管平滑肌細胞所產生的羥基自由基。
本篇論文證實了PMC可經由抑制羥基自由基所引發的PLCγ1-PKCδ和JAK2-STAT3訊息傳遞路徑的活化，而導致細胞週期停滯在G2/M期，進而抑制血管平滑肌細胞增生，此一抑制效果為PMC抑制氣球擴張術引發血管內膜不正常增生之可能機轉。根據研究結果發現，PMC可能是一種具潛力的藥物以治療血管內膜增生相關的疾病。

關鍵字

pentamethylhydroxychromane ； 維生素E衍生物 ； 血管平滑肌細胞 ； PLC ； JAK2 ； 羥基自由基

並列摘要

Abnormal proliferation of vascular smooth muscle cells (VSMCs) play important roles in the development of cardiovascular diseases. PMC (2,2,5,7,8-pentamethyl-6-hydroxychromane) is the most potent hydrophilic derivative of the vitamin E. In this study, we investigated the inhibitory mechanisms of PMC on VSMC proliferation in vitro and in vivo. PMC (20 and 50 μM) obviously suppressed cell proliferation of PDGF-BB-stimulated cells but not resting cells, and arrested cell cycle progression at the G2/M phase. A significant reduction of neointimal formation in carotid arteries was observed in PMC (5 mg/kg/day)-treated rats after balloon angioplasty. Activations of STAT3, JAK2, PLCγ1, PKCδ, and ROS, but not ERK1/2, AKT, or PKCα?z were markedly inhibited by PMC in PDGF-BB-stimulated VSMCs. Deferoxamine and PMC significantly inhibited the phosphorylation of PLCγ1 and JAK2 and arrested cell cycle progression at the G2/M phase. These events, however, were reversed in the presence of Fe2+. Moreover, PMC directly inhibited hydroxyl radical formation in both the Fenton reaction and VSMCs according to an electron spin resonance study. In conclusion, this study demonstrates for the first time that PMC inhibited VSMC proliferation in vitro, and balloon injury-induced neointimal formation in vivo. The inhibitory mechanisms of PMC may be involved in the inhibition of hydroxyl radical-mediated PLCγ1-PKCδ and JAK2-STAT3 activation, and causes cell cycle arrest at the G2/M phase. PMC treatment may represent a novel approach for lowering the risk of or improving the function in abnormal VSMC proliferation-related vascular diseases.

並列關鍵字

pentamethylhydroxychromane ； vitamin E derivative ； VSMC ； PLC ； JAK2 ； hydroxyl radical

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