左旋多巴对大鼠中脑小胶质细胞的影响

发布时间：2018-03-03 03:28

本文选题：帕金森病　切入点：6-羟多巴胺　出处：《福建医科大学》2014年硕士论文　论文类型：学位论文

【摘要】：帕金森病(Parkinson,s disease，PD)是一种常见的神经系统退行性疾病，以中脑黑质致密部多巴胺（DA）能神经元变性坏死和出现Lewy小体为主要病理特点。左旋多巴（L-Dopa）是PD治疗上的主要药物之一，目前关于L-Dopa的毒性存在争议，长期的动物体内研究与临床研究结论不一。6-OHDA制作的PD模型能模拟PD的病理过程，模型中可以观察到小胶质细胞的激活及炎症因子TNF-α等增加，最终介导DA能神经元的缺失。本实验以6-OHDA的PD模型为对照，观察L-Dopa的脑内直接注射以及灌胃给药能否产生类似6-OHDA的毒性，引起小胶质细胞的增生激活并介导DA能神经元的损伤，初步探讨L-Dopa可能的毒性，为临床L-Dopa的安全合理用药提供依据。 1、方法：（1）取SD大鼠，随机分成实验组与对照组，实验组大鼠左侧纹状体内分别注射6-OHDA(5ug/uL)、不同剂量L-Dopa（50ug/uL、5ug/uL、1ug/uL），对照组注射等量生理盐水；（2）取SD大鼠，随机分成实验组与对照组，实验组大鼠灌胃分别给不同剂量L-Dopa（200mg/kg.d、100mg/kg.d、10mg/kg.d），对照组注射等量生理盐水；（3）术后观察各组经阿朴吗啡诱导后大鼠旋转行为的改变；（4）术后4周取实验组和对照组脑组织行免疫组织化学染色，观察黑质DA能神经元数量变化；行免疫荧光技术染色,观察大鼠中脑黑质致密部中的小胶质细胞激活情况及TNF-α水平的改变； 2、结果：（1）与对照组相比，术后4周6-OHDA诱导的PD大鼠模型可观察到脑黑质中小胶质细胞的激活（P0.001）、TNF-α水平的增高（P0.001）及DA能神经元的减少（P0.001）；（2）与对照组相比，术后4周直接脑内注射高剂量L-Dopa的正常大鼠可观察到脑黑质中小胶质细胞的激活（P0.05）、TNF-α水平的增高（P0.05）及DA能神经元的减少（P0.05）；（3）与对照组相比，术后4周正常大鼠直接脑内注射中、低剂量L-Dopa、灌胃给各剂量L-Dopa未发现脑黑质中小胶质细胞的激活（P0.05）、TNF-α水平的增高（P0.05）及DA能神经元的减少（P0.05）。 3、结论：（1）健康大鼠脑内直接注射高浓度L-Dopa可产生与6-OHDA相似的神经毒性，即引起小胶质细胞的激活及DA能神经元的受损，但一般口服剂量L-Dopa对健康大鼠没有发现神经毒性。（2）不能排除在脑内已有严重病理变化的情况下，口服大剂量L-Dopa对DA能神经元产生毒性的可能性。
[Abstract]:Parkinsonian disease (PDD) is a common neurodegenerative disease, characterized by degeneration and necrosis of dopaminergic neurons in the substantia nigra compact region and the presence of Lewy corpuscles. L-Dopaus is one of the main drugs in the treatment of PD. At present, the toxicity of L-Dopa is controversial. The PD model made by 6-OHDA can simulate the pathological process of PD. The activation of microglia and the increase of inflammatory factor TNF- 伪 can be observed in the model. In this experiment, we used the PD model of 6-OHDA as the control, to observe whether L-Dopa could produce the toxicity similar to 6-OHDA, induce the proliferation and activation of microglia and mediate the damage of DA neurons. To explore the possible toxicity of L-Dopa and to provide evidence for the safe and rational use of L-Dopa. 1. Methods:. Sprague-Dawley rats were randomly divided into experimental group and control group. The left striatum of experimental group was injected with 6-OHDA-5ug-uLX respectively. The rats in the control group were injected with the same amount of normal saline. (2) Sprague-Dawley rats were randomly divided into experimental group and control group. Rats in the experimental group were given different doses of L-Dopaus 200mg / kg / kg / kg / 100 mg / kg / kg / kg / kg / d respectively, and the control group was injected with the same amount of normal saline. The rotation behavior of rats induced by apomorphine was observed after operation. Four weeks after operation, the brain tissues of the experimental group and the control group were taken for immunohistochemical staining to observe the changes of DA neurons in the substantia nigra, and immunofluorescence staining was performed to observe the changes of DA neurons in the substantia nigra. The activation of microglia and the level of TNF- 伪 in the substantia nigra were observed. 2. Results:. (1) compared with the control group, the PD rat model induced by 6-OHDA at 4 weeks after operation showed the increase of the level of TNF- 伪 and the decrease of dopaminergic neurons in the substantia nigra (P 0.001) and the decrease of dopaminergic neurons (P 0.001). (2) compared with the control group, 4 weeks after operation, the normal rats injected with high dose L-Dopa directly into the brain could observe the increase of the level of TNF- 伪 in the substantia nigra and the decrease of dopaminergic neurons (P0.05). (3) compared with the control group, low dose L-Dopaas and intragastric administration of L-Dopa did not show the increase in the level of TNF- 伪 and the decrease of dopaminergic neurons in the substantia nigra (P0.05) and the decrease of DA neurons in normal rats 4 weeks after operation. 3. Conclusion:. 1) the neurotoxicity of L-Dopa was similar to that of 6-OHDA, that is, the activation of microglia and the damage of DA neurons were induced by direct intracerebral injection of L-Dopa into the brain of healthy rats, but no neurotoxicity was found in healthy rats at the general oral dose of L-Dopa. 2) the possibility of toxicity of high dose L-Dopa to DA neurons can not be ruled out in the presence of severe pathological changes in the brain.
【学位授予单位】：福建医科大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R742.5

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