PrP~c在睡眠剥夺所致认知损害中的作用及可能的机制研究

发布时间：2018-07-04 15:04

  本文选题：细胞型朊蛋白 + 睡眠剥夺　； 参考：《第二军医大学》2017年硕士论文

【摘要】：【目的】随着生活节奏和工作压力的增加,睡眠障碍的现象越来越普遍,以往研究表明睡眠障碍是阿尔茨海默病(Alzheimer’s disease,AD)的临床症状之一。目前的研究发现睡眠障碍不仅是AD的症状,还有可能是AD发病的危险因素。细胞型朊蛋白(Cellular prion protein,PrP~c)是一种高度保守的在中枢神经系统高表达的膜蛋白,其生理功能目前尚不清楚,但有研究证实PrPC在睡眠调节和记忆形成与巩固过程发挥重要作用。有研究显示小鼠视交叉上核和顶叶皮层PrPC mRNA具有昼夜节律变化,提示PrP~c可能存在昼夜节律性;有研究发现PrP~c可抑制关键酶β-分泌酶(β-secretase,BACE1)活性,调节APP的分解,从而影响Aβ的产生。另外,研究已经证实睡眠剥夺在导致认知功能损害的同时伴随Aβ表达上调,提示睡眠剥夺诱导认知功能损害可能与PrP~c对Aβ的影响有关,PrP~c可能具有潜在神经保护作用。探讨PrP~c在睡眠剥夺所致认知损害中发挥的作用,有可能为认知障碍疾病找到潜在治疗靶点。【方法】选取C57B L/6小鼠,按体重大小随机分成6组,正常饲养2周以建立正常睡眠-觉醒周期,分别于24h内6个不同时间点获取取海马和皮层组织样本,采用ELISA方法检测PrP~c与Aβ的表达水平变化,以判断是否存在昼夜节律变化。其次,选取C57B L/6小鼠,随机分成CC组、EC组、SD组,采用改良水平台法进行72h睡眠剥夺后获取海马组织,采用Western Blot检测PrP~c和ELISA方法检测Aβ表达变化以观察睡眠剥夺后小鼠海马PrP~c与Aβ的表达情况。第三,采用脑立体定位注射技术在小鼠海马注射PrP~c过表达腺相关病毒,观察PrP~c过表达是否能改善睡眠剥夺引起的小鼠空间记忆损害。【结果】本研究结果显示(1)C57B L/6小鼠脑内Aβ在24小时正常睡眠-觉醒周期中6个不同时间点出现有统计学意义的波动性变化(P0.05);单余弦分析结果显示PrPC在皮层部位存在昼夜节律性(F=11.22,P0.05)。Aβ在海马部位具有昼夜节律性(F=26.72,P0.05)。(2)睡眠剥夺后海马PrPC的表达在SD组(0.22±0.05)较CC组(0.64±0.16)和EC组(0.58±0.09)明显下调(F=4.366,P0.05);Aβ的表达在SD组(13.03±0.71)较CC组(8.22±0.8)和EC组(8.6±0.57)明显上调(F=14.511,P0.05)。(3)海马内注射腺相关病毒使PrP~c过表达可以改善睡眠剥夺诱导的海马空间记忆损害,过表达组目标象限时间百分比显著高于对照组(F=6.196,P0.05)。【结论】首次发现,小鼠皮层PrPC的表达在正常睡眠-觉醒周期下表现为昼夜节律变化,在觉醒期达到高峰,急性睡眠剥夺可导致海马内PrPC表达下降,提示小鼠脑内PrPC表达水平与睡眠相关。其次,海马内PrPC过表达可以改善睡眠剥夺后空间记忆损害。提示PrPC具有潜在神经保护作用。
[Abstract]:[objective] with the increase of life rhythm and work stress, sleep disorder is becoming more and more common. Previous studies have shown that sleep disorder is one of the clinical symptoms of Alzheimer's disease (AD). Current studies have found that sleep disorder is not only a symptom of AD, but also a risk factor for AD. Cellular prion protein (prion) is a highly conserved membrane protein expressed in the central nervous system (CNS), and its physiological function is not clear, but it has been confirmed that it plays an important role in the process of sleep regulation and memory formation and consolidation. Some studies have shown that PrPC mRNA in suprachiasmatic nucleus and parietal cortex has circadian rhythm, suggesting that PrPnc may have circadian rhythm, and it has been found that PrPcc can inhibit the activity of 尾 -secretase (尾 -secretase) and regulate the decomposition of app, thus affecting the production of A 尾. In addition, it has been confirmed that sleep deprivation may lead to cognitive impairment accompanied by up-regulation of A 尾 expression, suggesting that sleep deprivation induced cognitive impairment may be related to the effect of PrPnc on A 尾 and may have a potential neuroprotective effect. To explore the role of PrPtroc in cognitive impairment induced by sleep deprivation, it is possible to find a potential therapeutic target for cognitive impairment. [methods] C57B / L / 6 mice were randomly divided into 6 groups according to their body weight. The normal sleep-wake cycle was established by normal feeding for 2 weeks. The hippocampal and cortical tissues were collected at 6 different time points within 24 hours. The expression levels of PrPnc and A 尾 were detected by Elisa to determine whether there were circadian rhythms. Secondly, C57B / L / 6 mice were randomly divided into CC group (EC group) and SD group. Hippocampal tissue was obtained after 72 h sleep deprivation by modified horizontal table method. The expression of A 尾 was detected by Western blot and Elisa in order to observe the expression of PrPnc and A 尾 in hippocampus of mice after sleep deprivation. Thirdly, using stereotactic injection technique, we injected PrPnc overexpression adeno-associated virus into the hippocampus of mice. [results] the present study showed that (1) A 尾 in the brain of C57B / L / 6 mice appeared at 6 different time points in the normal sleep / arousal cycle of 24 hours. [results] the results showed that A 尾 in the brain of C57B / L / 6 mice was regulated at 6 different time points during the normal sleep / wake-up cycle of 24 hours. The results of single cosine analysis showed that there was circadian rhythm in cortical area (F _ (11.22) P _ (0.05) .A 尾 in hippocampus (F _ (26.72) P _ (0.05). (_ 2). The expression of PrPC in hippocampus after sleep deprivation was (0.22 卤0. 05) in SD group compared with (0.64 卤0.16) in CC group and (0.58 卤0.09) in EC group. In SD group (13.03 卤0.71), compared with CC group (8.22 卤0.8) and EC group (8.6 卤0.57), the down-regulated expression of). (尾 was significantly up-regulated (F _ (14. 511) P 0.05 /). (_ 3). The overexpression of PrPc in hippocampus induced by sleep deprivation could improve the spatial memory impairment of hippocampus induced by sleep deprivation, and the expression of PrPc 尾 was significantly up-regulated in SD group (P < 0.05), compared with that in CC group (8.22 卤0.8) and EC group (8.6 卤0.57). The percentage of target quadrant time in the overexpression group was significantly higher than that in the control group (P 0.05). [conclusion] it was found for the first time that the expression of PrPC in the cortex of mice showed circadian rhythm changes during normal sleep-wake cycle, and reached its peak at the awakening stage. Acute sleep deprivation resulted in a decrease in the expression of PrPC in the hippocampus, suggesting that the expression level of PrPC in the brain of mice was related to sleep. Secondly, overexpression of PrPC in hippocampus can improve spatial memory impairment after sleep deprivation. The results suggest that PrPC has potential neuroprotective effect.
【学位授予单位】：第二军医大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R740

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中国期刊全文数据库 前1条

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