杜鹃素对LPS诱发的帕金森病模型的神经保护作用及其机制

发布时间：2018-07-12 19:10

本文选题：杜鹃素 + 小胶质细胞　；参考：《吉林大学》2017年硕士论文

【摘要】：近年来,大量研究表明神经炎症在神经退行性疾病的发生发展过程中起到重要作用。对死后PD病人剖检及6-羟多巴胺(6-OHDA)和MPTP诱导的PD动物模型中都发现中脑黑质区存在小胶质细胞异常活化的现象。小胶质细胞是神经炎症反应的主要效应细胞,其数量仅占胶质细胞总数的20%[1]。神经炎症过程中小胶质细胞被过度活化后,能产生一些细胞毒性因子(IL-1β、IL-6、TNF-α、NO和PGE2等),这些细胞毒性因子可以导致周围的神经元发生损伤,损伤神经元释放的损伤相关模式分子可以进一步活化小胶质细胞,从而产生更多细胞毒性因子进一步损伤周围的神经元[2]。目前已经有研究表明,抗炎药物能减少PD的患病率。因此,抑制小胶质细胞活化可能对PD起到治疗或缓解作用。杜鹃素(Farrerol)是提取自满山红或者其他杜鹃属植物的一种黄酮类化合物,在体内起到抗炎、抗氧化和免疫抑制等多方面的功能[3]。有研究结果显示[4,5],杜鹃素在疾病中的很多积极作用都与其参与调节NF-κB通路的激活相关;另外,杜鹃素可通过抑制促炎蛋白酶类(iNOS和COX-2)及其产物NO和PGE2来达到减轻炎症的作用,所以,我们推测在PD中杜鹃素可能通过抑制神经炎症反应从而对PD起到治疗和缓解作用。因此,本实验通过建立LPS诱导的体外神经炎症反应细胞模型和体内PD动物模型,研究了杜鹃素对神经炎症介导的PD模型的影响及其作用机制。通过对小胶质细胞系BV-2细胞的研究发现,杜鹃素对LPS诱导的炎症模型中促炎细胞因子(IL-6、IL-1β和TNF-α)及促炎蛋白酶类(iNOS和COX-2)表达具有显著的抑制作用,且呈剂量依赖性。同时,杜鹃素也可以显著抑制LPS诱导的BV-2细胞中NO和PGE2产量的增加。另外,通过Western blot方法检测杜鹃素对LPS诱导的MAPKs、NF-κB和Akt信号通路关键节点磷酸化水平的影响,结果发现杜鹃素可以显著抑制LPS诱导的NF-κB p65和Akt的磷酸化水平,但对MAPKs通路中ERK1/2、p38和JNK1/2的磷酸化水平没有影响。以上结果表明,杜鹃素可以显著抑制LPS在BV-2细胞中诱导的炎症反应,其机制可能是通过抑制NF-κB p65和Akt的磷酸化。为了进一步确定杜鹃素的抗神经炎症功能对PD的影响,我们通过在中脑黑质区注射LPS建立PD动物模型,并腹腔注射杜鹃素研究其对PD的治疗作用。结果显示,杜鹃素可以显著抑制阿扑吗啡诱导的PD动物模型的旋转行为;机制研究发现,杜鹃素显著抑制PD动物模型中中脑黑质区小胶质细胞的激活以及多巴胺能神经元的减少。以上研究结果表明,杜鹃素可以通过抑制NF-κB-p65和Akt的磷酸化改善LPS在小胶质细胞中诱导的炎症反应;此外,杜鹃素在PD动物模型中通过抑制小胶质细胞介导的神经炎症反应过程中对多巴胺能神经元起到保护作用。因此,杜鹃素有望成为PD治疗的有效药物。
[Abstract]:In recent years, a large number of studies have shown that neuroinflammation plays an important role in the occurrence and development of neurodegenerative diseases. Abnormal activation of microglia in substantia nigra was found in postmortem PD patients, 6-OHDA (6-OHDA) and MPTP induced PD animal models. Microglial cells are the main effector cells of neuroinflammatory reaction, which only account for 20% of the total number of glial cells [1]. In the process of neuroinflammation, microglia are over-activated and produce some cytotoxic factors (IL-1 尾, IL-6, TNF- 伪, no, PGE2, etc.). These cytokines can cause damage to the surrounding neurons. Injury-related model molecules released by injured neurons can further activate microglia and produce more cytotoxic factors to further damage the surrounding neurons [2]. Studies have shown that anti-inflammatory drugs can reduce the prevalence of PD. Therefore, inhibition of microglial activation may play a therapeutic or remission role in PD. Farrerol is a flavonoid extracted from Rhododendron or other Rhododendron plants. Farrerol has many functions of anti-inflammatory, anti-oxidation and immunosuppressive in vivo [3]. Some studies have shown that Rhododendron is involved in regulating the activation of NF- 魏 B pathway in many of its positive roles in the disease. In addition, rhododendronin can attenuate inflammation by inhibiting proinflammatory proteases (iNOS and COX-2) and their products, no and PGE2. Therefore, we speculate that rhododendron may play a therapeutic and remission role in PD by inhibiting neuroinflammatory response. Therefore, the effects of rhododendron on neuroinflammatory PD model induced by LPS in vitro and PD animal model in vivo were studied. Through the study of microglial cell line BV-2, it was found that rhododendron inhibited the expression of pro-inflammatory cytokines (IL-6, IL-1 尾 and TNF- 伪) and pro-inflammatory proteases (iNOS and COX-2) in a dose-dependent manner. At the same time, rhododendron could significantly inhibit the increase of no and PGE2 production in BV-2 cells induced by LPS. In addition, the effects of rhododendron on LPS-induced phosphorylation of NF- 魏 B and Akt key nodes in MAPK- 魏 B and Akt signaling pathway were detected by Western blot. The results showed that Rhododendron could significantly inhibit the phosphorylation of LPS-induced NF- 魏 B p65 and Akt. But there was no effect on the phosphorylation levels of ERK1 / 2 p38 and JNK1 / 2 in MAPKs pathway. These results suggest that Rhododendron can significantly inhibit the inflammatory response induced by LPS in BV-2 cells by inhibiting the phosphorylation of NF- 魏 B p65 and Akt. In order to further determine the effect of rhododendron on PD, we established PD animal model by injecting LPS into substantia nigra of mesencephalon, and intraperitoneally injected rhododendron to study the therapeutic effect of Rhododendron on PD. The results showed that rhododendron could significantly inhibit the rotational behavior of PD model induced by apomorphine. Rhododendron significantly inhibited the activation of microglia and the decrease of dopaminergic neurons in substantia nigra in PD animal model. These results suggest that Rhododendron can improve the LPS-induced inflammatory response in microglia by inhibiting the phosphorylation of NF- 魏 B-p65 and Akt. Rhododendron protects dopaminergic neurons by inhibiting neuroinflammatory responses mediated by microglia in PD animal models. Therefore, rhododendron is expected to be an effective drug in the treatment of PD.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R285.5;R-332

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