MK-801处理青春期大鼠制作精神分裂症认知损伤模型和非经典抗精神病药物治疗机制研究

发布时间：2018-06-10 08:28

本文选题：MK-801 + 认知功能损伤　；参考：《复旦大学》2013年博士论文

【摘要】：第一部分 MK-801对青春期大鼠认知功能和海马神经细胞突触的影响背景：认知障碍是精神分裂症的核心症状之一。研究发现突触生长缺陷与认知障碍有关。尸检研究也发现精神分裂症患者海马神经细胞也存在突触生长缺陷。NMDA受体在青春期大脑发育的关键时期通过调节突触修剪和稳定而对大脑发育起了关键作用。非竞争性NMDA受体阻断剂常被用来制作精神分裂症认知障碍动物模型。目的：探索青春发育期阻断NMDA受体是否会导致海马神经细胞的突触生长缺陷,并最终导致认知障碍。方法：雄性青春期大鼠接受14天MK-801(0.2mg/kg i.p qd)或相等容积的生理盐水的腹腔注射后,观察它们的空间记忆能力、树突棘形态变化、突触前和突触后标志物(SYP和PSD-95)的蛋白表达量以及突触生长相关因子RhoA、Rac1和Cdc42基因表达水平的变化。结果：我们发现亚慢性MK-801使青春期大鼠认知功能损伤,海马神经细胞的树突棘头直径缩小。同时,亚慢性MK-801使青春期大鼠海马神经细胞内的突触素和PSD-95的蛋白表达量明显下降,RhoA mRNA表达水平上升但是Rac1和Cdc42的mRNA水平明显下降。结论：青春发育期如果NMDA受体受到阻断会导致海马神经细胞的突触生长缺陷这次的研究结果为探索精神分裂症认知障碍的发病机制提供了一个新的研究方向。第二部分奥氮平、利培酮和喹硫平对MK-801精神分裂症模型大鼠认知和海马小清蛋白阳性中间神经元的影响背景：认知障碍是精神分裂症的核心症状之一。非经典抗精神病药物能用来治疗认知障碍。但是非经典抗精神病药物(APDs)改善认知损伤的机制至今不明。尸检和关联研究均证明PV中间神经元的突触抑制功能障碍与精神分裂症患者认知障碍密切相关。亚慢性MK-801能诱导青春期大鼠出现类似于精神分裂症认知障碍症状和PV中间神经元数量下降等神经病理学改变。目的：选择临床常用的奥氮平、利培酮和喹硫平这三种APDs,作用于MK-801模拟分裂症认知损伤模型大鼠,观察大鼠的空间记忆认知功能和海马小清蛋白中间神经元密度的改变。方法：40只青春期雄性大鼠随机分成5组(n=8)：对照组、MK-801组、奥氮平组、利培酮组、喹硫平组。对照组接受生理盐水(1ml/kg i.p qd)14天,其余大鼠接受MK-801(0.2mg/kg i.p qd)14天。造模结束24小时后,对照组和MK-801组大鼠蒸馏水灌胃(1ml/Kgi.g qd),其余三组分别接受奥氮平(2.5mg/kg ig qd)、利培酮(1mg/kg ig qd)口喹硫平(25mg/kg ig qd)给药10天。之后利用水迷宫试验测量大鼠空间记忆能力和游泳速度,通过免疫组化方法检测海马PV阳性细胞密度。结果：研究结果显示,MK-801造成青春期大鼠认知功能的损伤和脑海马区PV中间神经元数量的下降。利培酮和喹硫平能缓解MK-801造成的空间记忆方面的认知损伤和海马区PV中间神经元减少。结论：保护海马区PV中间神经元可能是非经典APDs改善精神分裂症患者的空间记忆方面的认知损伤的重要机制。第三部分喹硫平通过激活5-HT1a突触前受体改善MK-801诱导的认知损伤背景：目前认知障碍的治疗已经成为精神科临床治疗的重点。非经典APDs能用来治疗认知障碍。但是非经典APDs改善认知损伤的机制至今不明。尸检研究发现精神分裂症患者脑内的5-HT1a受体密度上升,这说明5HT1a受体功能异常。既往在精神病学领域关于5-HTla受体的研究多集中在情绪障碍方面,最近几年5-HT1a受体与认知功能的关联受到越来越多的关注。非经典APDs很可能通过影响5-HT1a受体功能来改善认知。喹硫平是5-HT.1a受体部分激动剂,对精神分裂症认知障碍有出色的疗效。另外,PKA是5-HT1a受体介导的最经典的信号传导通路cAMP-PKA通路中最重要的信号因子之一,对认知功能有着重要的调节作用。5-HT1a突触前受体被激活时导致PKA活性上升,而5-HT1a突触后受体被激活时导致PKA活性下降。目的：利用精神分裂症认知损伤动物模型来明确喹硫平是否通过激活5-HT1a受体功来改善认知功能,并选择观察PKA活性变化来探讨喹硫平通过何种机制作用于5-HT1a受体来改善认知功能。方法：50只青春期雄性大鼠随机分成5组(n=10)：对照组、MK-801组、喹硫平组、坦度螺酮加喹硫平组和WAY100635加喹硫平组。对照组接受生理盐水(1ml/kg i.pqd)14天,其余的大鼠接受MK-801(0.2mg/kg i.pqd)14天。造模结束24小时后,对照组和MK-801组大鼠蒸馏水灌胃(1ml/Kg i.g qd),其余三组分别接受喹硫平(25mg/kg i.gqd)、喹硫平(25mg/kgi.gqd)和坦度螺酮(0.6mg/kgi.gqd)、喹硫平(25mg/kgi.gqd)和WAY100635(0.1mg/kg i.g qd)给药10天。之后利用水迷宫试验测量大鼠空间记忆能力和游泳速度,通过PKA检测试剂盒检测海马细胞内的PKA活性。结果：喹硫平组和坦度螺酮加喹硫平组大鼠认知功能显著高于MK-801组。WAY100635加喹硫平组大鼠的认知功能显著低于喹硫平组,而与MK-801组大鼠相比无显著差异。而坦度螺酮加喹硫平组大鼠的认知功能与喹硫平组的大鼠无明显差异。海马细胞内的PKA活性分析结果显示,喹硫平组和坦度螺酮加喹硫平组显著高于对照组和MK-801组。坦度螺酮加喹硫平组显著高于喹硫平组。WAY100635加喹硫平组则显著低于喹硫平组。结论：激活5-HT1a突触前受体后增强海马细胞PKA活性是喹硫平改善MK-801导致的青春期大鼠的认知功能损伤的重要机制之一。这些发现为研发更有效的精神分裂症认知障碍治疗药物和方法提供了新思路。
[Abstract]:Part one
Effects of MK-801 on cognitive function and synapse of hippocampal neurons in pubertal rats
Background: cognitive impairment is one of the core symptoms of schizophrenia. The study found that synaptic growth defects are associated with cognitive impairment. Autopsy studies have also found that the hippocampal neurons in the schizophrenic patients also have synaptic growth defect.NMDA receptors in the critical period of adolescent brain development through regulating synaptic pruning and stabilizing the brain. Non competitive NMDA receptor blockers are often used to produce animal models of cognitive impairment in schizophrenia.
Objective: To explore whether the blocking of NMDA receptors in the puberty period can lead to synaptic growth defects in the hippocampal neurons and eventually lead to cognitive impairment. Methods: male puberty rats received 14 days of MK-801 (0.2mg/kg i.p QD) or equal volume of physiological saline intraperitoneal injection to observe their spatial memory ability and the morphological changes of dendritic spines. The expression levels of presynaptic and postsynaptic markers (SYP and PSD-95) and the expression levels of RhoA, Rac1 and Cdc42 genes of synaptogenesis related factors were also changed.
Results: we found that subchronic MK-801 caused cognitive impairment in puberty rats and the diameter of dendritic spines in hippocampal neurons reduced. At the same time, subchronic MK-801 decreased the protein expression of synaptophysin and PSD-95 in the hippocampus neurons of puberty rats. The level of RhoA mRNA expression rose but the mRNA level of Rac1 and Cdc42 was obviously lower. Drop.
Conclusion: the study of synaptic growth defects in the hippocampal neurons by blocking NMDA receptors in the puberty period provides a new direction for exploring the pathogenesis of cognitive impairment of schizophrenia.
The second part
Effects of olanzapine, risperidone and quetiapine on cognitive and hippocampal parvalbumin positive interneurons in MK-801 schizophrenia rats
Background: cognitive impairment is one of the core symptoms of schizophrenia. Non classical antipsychotic drugs can be used to treat cognitive impairment. However, the mechanisms of non classic anti psychotic drugs (APDs) to improve cognitive impairment are still unknown. Autopsy and association studies have proved that synaptic inhibition dysfunction in PV intermediate neurons and cognition of schizophrenic patients The disorders are closely related. Subchronic MK-801 can induce neuropathological changes in adolescent rats similar to the symptoms of cognitive impairment in schizophrenia and the decrease in the number of PV intermediate neurons.
Objective: to select three APDs, the commonly used olanzapine, risperidone and quetiapine, to simulate the MK-801 model of schizophrenic cognitive impairment rats, and to observe the spatial memory cognitive function of the rats and the changes in the density of the intermediate neurons of the hippocampal small albumin.
Methods: 40 male male rats were randomly divided into 5 groups (n=8): control group, MK-801 group, olanzapine group, risperidone group and quetiapine group. The control group received physiological saline (1ml/kg i.p QD) for 14 days, and the rest rats received MK-801 (0.2mg/kg i.p QD) for 14 days. The control group and MK-801 group rats were filled with distilled water after 24 hours (1ml/Kgi.g QD). The remaining three groups were treated with olanzapine (2.5mg/kg Ig QD) and risperidone (1mg/kg Ig QD) quetiapine (25mg/kg Ig QD) for 10 days. Then the water maze test was used to measure the spatial memory ability and swimming speed of rats. The density of hippocampal PV positive cells was detected by immunohistochemical method.
Results: the results showed that MK-801 caused the impairment of cognitive function in puberty rats and the decrease in the number of PV intermediate neurons in the hippocampus of the brain. Risperidone and quetiapine could alleviate the cognitive impairment in spatial memory caused by MK-801 and the decrease of PV intermediate neurons in the hippocampus.
Conclusion: protection of hippocampal PV interneurons may be an important mechanism for non classical APDs to improve cognitive impairment in patients with schizophrenia.
The third part
Quetiapine improves MK-801 induced cognitive impairment by activating 5-HT1a presynaptic receptor
Background: treatment of cognitive impairment has now become the focus of clinical therapy in the psychiatric department. Nonclassical APDs can be used to treat cognitive impairment. However, the mechanism of non classic APDs to improve cognitive impairment is unknown. Autopsy studies have found that the density of 5-HT1a receptors in the brain of schizophrenic patients is rising, which indicates that the function of 5HT1a receptors is abnormal. The study of the 5-HTla receptor in the field of the neurology is mostly focused on emotional disorders. The association of 5-HT1a receptors with cognitive functions has attracted more and more attention in recent years. Non classical APDs is likely to improve cognition by affecting the function of 5-HT1a receptor. Quinolapine is a partial irritable agent of 5-HT.1a receptor, which is excellent for cognitive impairment of schizophrenia. In addition, PKA is one of the most important signal factors in the most classic signal transduction pathway cAMP-PKA pathway mediated by 5-HT1a receptor, which plays an important regulatory role in cognitive function, which leads to the increase of PKA activity when the.5-HT1a presynaptic receptor is activated, and the PKA activity decreases when 5-HT1a postsynaptic receptors are activated.
Objective: to make use of the animal model of cognitive impairment of schizophrenia to determine whether quetiapine can improve cognitive function by activating 5-HT1a receptor work, and to observe the changes in PKA activity to explore the mechanism of quetiapine to improve the cognitive function through the mechanism of 5-HT1a receptor. Methods: 50 young spring male rats were randomly divided into 5 groups (n=10): Group MK-801, quetiapine group, tedipine plus quetiapine group and WAY100635 plus quetiapine group. The control group received physiological saline (1ml/kg i.pqd) for 14 days, the rest of the rats received MK-801 (0.2mg/kg i.pqd) for 14 days. After the end of the model 24 hours, the control group and MK-801 group rats were distilled water (1ml/Kg i.g QD), and the other three groups were treated with quetiapine (25). Mg/kg i.gqd), quetiapine (25mg/kgi.gqd) and stapone (0.6mg/kgi.gqd), quetiapine (25mg/kgi.gqd) and WAY100635 (0.1mg/kg i.g QD) were administered for 10 days. Then the spatial memory ability and swimming speed of rats were measured by water maze test, and PKA activity in hippocampal cells was detected by PKA detection kit.
Results: the cognitive function of the rats in the quetiapine group and the quetiapine group was significantly higher than that in the group MK-801.WAY100635 and quetiapine group, and the cognitive function of the rats in the quetiapine group was significantly lower than that in the quetiapine group, but there was no significant difference compared with that of the MK-801 group. The analysis of PKA activity in horse cells showed that the quetiapine group and the ququetapine group were significantly higher than those in the control group and the MK-801 group. The group of the quetiapine and the quetiapine group was significantly higher than the quetiapine group and the quetiapine group was significantly lower than the quetiapine group, which was significantly lower than that in the quetiapine group.
Conclusion: the activation of PKA activity in hippocampal cells by activating 5-HT1a presynaptic receptor is one of the important mechanisms of quetiapine to improve cognitive impairment in MK-801 induced puberty rats. These findings provide a new way for developing more effective therapeutic drugs and methods for cognitive impairment of schizophrenia.
【学位授予单位】：复旦大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：R749.3;R-332

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