自闭症模型大鼠各生长发育阶段的脑组织中m-GABA_AR的表达情况及相关机制研究

发布时间：2018-03-28 10:04

本文选题：自闭症谱系障碍　切入点：GABA_AR内吞作用　出处：《重庆医科大学》2017年硕士论文

【摘要】：背景;自闭症谱系障碍主要表现为:1、社交沟通障碍;2、刻板重复的行为和兴趣狭窄。其发病机制长期困扰着全世界的专家学者们,同时由于其发病机制尚不明确,使有效的治疗措施的发现变得难上加难。目前,‘兴奋抑制失衡’理论被广泛认可和接受,该理论认为大脑中异常的兴奋/抑制信号传导引起了自闭症患儿的一系列异常行为表现。其中抑制信号的传导与GABA_AR关系十分紧密,所以GABA_AR的异常及其偶联的离子共转运体NKCC1和KCC2的异常无疑会影响抑制性信号的传导。同时,自闭症谱系障碍作为一种发育性障碍,大多情况下在患儿3岁时才能被明确诊断,但大量证据表明其损伤性的病变在生命的早期阶段便开始了。目的;探讨自闭症模型大鼠中各个生长发育阶段GABA_AR的变化情况及行为异常。方法:使用VPA诱导的自闭症模型大鼠作为实验组,VPA溶解于生理盐水。对照组为仅暴露于生理盐水的子代大鼠。从出生后0天开始对其生长发育情况进行测评,包括平面翻正、空中翻正、负趋地性、断崖回避、听觉惊愕作为其神经发育的指标,而体重、立耳、牙齿萌出、睁眼情况则反映了其身体发育情况。出生后35天起,进行Morris水迷宫、矿场实验和三箱实验,检测其空间记忆、焦虑状态、对陌生环境探索的兴趣及社交行为。然后运用Western blot的方法分别检测PD7、PD14、PD28、PD56大鼠4个脑区中GABA_ARβ3、m-GABA_ARβ3、p-GABA_ARβ3、KCC2、NKCC1的表达量。各个时间点的脑组织来源于按随机原则从相应时间点的两组中选取的6只大鼠(模型组和对照组各3只)。结果:(1)自闭症模型大鼠身体发育情况较对照组无名明显差异,但神经发育情况明显滞后于对照组。(2)通过Morris水迷宫实验,我们发现自闭症模型大鼠存在一定的空间记忆障碍和相对低下的运动能力;在矿场实验中,自闭症大鼠则表现出了明显的焦虑状态和减少的探索性趣;三箱实验中模型组则有明显的社交障碍的表现。(3)自闭症模型大鼠各时间点各脑区与对照组相比,m-GABA_ARβ3、pGABA_ARβ3、KCC2的表达量均减少,但总的GABA_ARβ3和NKCC1的表达并无显著差异。结论:(1)自闭症模型大鼠除表现出核心症状社交障碍和探索兴趣下降外,还表现出明显的神经发育迟滞、焦虑状态、运动协调能力下降及空间记忆障碍。(2)自闭症模型大鼠各时间点各脑区均有GABA_AR的异常。(3)引起该异常的机制之一可能是GABA_ARβ3去磷酸化介导的GABA_AR内吞作用增加。
[Abstract]:Background: autism spectrum disorders are mainly expressed as: 1, social communication, stereotypical behavior and narrow interests. The pathogenesis of autism spectrum disorders has long plagued experts and scholars all over the world, while the pathogenesis of autism spectrum is still unclear. It makes the discovery of effective treatment even more difficult. Currently, the theory of "excitation-suppression imbalance" is widely accepted and accepted. The theory suggests that abnormal excitatory / inhibitory signal transduction in the brain causes a series of abnormal behaviors in autistic children. The inhibitory signal transduction is closely related to GABA_AR. So the abnormality of GABA_AR and its coupling ion cotransporter NKCC1 and KCC2 will undoubtedly affect the signal transduction of inhibition. Meanwhile, autism spectrum disorder, as a developmental disorder, is usually diagnosed at the age of 3. But there is plenty of evidence that the lesion begins at an early stage of life. To investigate the changes and behavioral abnormalities of GABA_AR in various growth and development stages of autistic rats. Methods: VPA induced autistic model rats were used as experimental groups to dissolve GABA_AR in normal saline, while those in control group were only exposed to physiological conditions. The offspring of saltwater. The growth and development of rats were evaluated from 0 days after birth. Including plane inversion, aerial inversion, negative geodesic, cliff avoidance, auditory consternation as indicators of neurodevelopment, and weight, ear, teeth eruption, and eye opening, which reflect their physical development. 35 days after birth, Morris water maze, field experiment and three-box experiment were carried out to detect their spatial memory and anxiety. The Western blot method was used to detect the expression of GABA_AR 尾 3, m-GABAAR 尾 3, p-GABAAR 尾 3, p-GABAAR 尾 3, KABAAR 尾 3 and KABAAR 尾 3 KCC2NKCC1 in four brain regions of PD7 / PD14 / PD28 / PD56 rats respectively. The brain tissue at each time point was derived from the two groups of corresponding time points according to random principle. Six rats (3 in model group and 3 in control group) were selected. Results the development of autistic rats was significantly different from that of unnamed rats in control group. But the neural development lags behind that of the control group. (2) through the Morris water maze experiment, we found that there are some spatial memory disorders and relatively low motor ability in the autistic model rats. The rats with autism showed obvious anxiety and decreased exploratory interest, while the model group showed obvious social disorder in the three-box experiment.) the expression of m-GABAAR 尾 3pGABAAR 尾 3pGABAAR 尾 3pGABAAR 尾 3KCC2 was decreased in each brain area of the model rats compared with the control group at each time point. But there was no significant difference between the expression of GABA_AR 尾 3 and NKCC1. Conclusion the rat model of autism not only showed the core symptoms of social disorder and decreased interest in exploration, but also showed obvious neurological retardation and anxiety. The decrease of motor coordination ability and spatial memory impairment. 2) there is abnormal GABA_AR in all brain regions of autism model rats at all time points.) one of the mechanisms of this abnormality may be the increase of GABA_AR endocytosis mediated by GABA_AR 尾 3 dephosphorylation.
【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R749.94;R-332

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