海马齿状回的内质网应激参与AD模型大鼠空间学习记忆损伤的机制  

Endoplasmic reticulum stress in hippocampal dentate gyrus is involved in spatial learning and memory impairment in rat model of AD

作　　者：肖斌[1] 任鹏 李明月 金清华[1] XIAO Bin;REN Peng;LI Ming-yue;JIN Qing-hua(Department of Physiology and Pathophysiology,College of Medicine,Yanbian University,Yanji 133002,China)

机构地区：[1]延边大学医学院生理与病理生理学教研室,吉林延吉133002

出　　处：《中国病理生理杂志》2021年第7期1163-1170,共8页Chinese Journal of Pathophysiology

基　　金：国家自然科学基金资助项目(No.81760158);吉林省教育厅“十三五”科学技术研究规划项目(No.JJKH20191137KJ);延边大学博士启动基金项目(No.602018033)。

摘　　要：目的:探讨海马齿状回(DG)的内质网应激(ERS)损伤阿尔茨海默病(AD)大鼠空间学习和记忆功能的分子机制。方法:60只SD系雄性大鼠(3月龄)随机分为空白(control)组和AD模型(AD)组,AD大鼠侧脑室注射1次链脲佐菌素(2.4 mg/kg),3 d后开始腹腔注射D-半乳糖(60 mg·kg^(−1)·d^(−1))共6周,而control大鼠以相同方法注射生理盐水。Morris水迷宫评估大鼠的空间学习记忆能力;透射电镜观察大鼠海马DG区超微结构;Westernblot法检测海马DG区的葡萄糖调节蛋白78(GRP78)、蛋白激酶R样内质网激酶(PERK)、Ca^(2+)/钙调蛋白依赖性蛋白激酶II(CaMKII)、细胞外信号调节激酶(ERK)和脑源性神经营养因子(BDNF)的水平,并通过腹腔注射ERS抑制剂4-苯基丁酸(4-PBA)和ERK通路抑制剂PD98059探讨DG区ERS损伤AD大鼠空间学习和记忆功能的下游机制。结果:与control大鼠比较,AD大鼠海马DG区的超微结构明显受损,包括突触结构损伤、粗面内质网排列紊乱及核糖体脱落,其ERS标志蛋白GRP78和p-PERK的水平显著升高(P<0.05)。与control大鼠比较,AD大鼠的空间学习和记忆能力显著下降(P<0.05),海马DG区p-CaMKII、p-ERK和BDNF的水平显著降低(P<0.05);4-PBA可改善AD大鼠的空间学习和记忆能力,同时提高海马DG区p-CaMKII、p-ERK和BDNF的水平(P<0.05)。利用PD98059抑制ERK通路可反转4-PBA增加AD大鼠海马DG区BDNF表达的作用(P<0.05)。结论:海马DG区ERS可能通过抑制CaMKII/ERK/BDNF通路损伤AD大鼠的空间学习和记忆功能。AIM:To investigate the molecular mechanism of endoplasmic reticulum stress(ERS)in hippo-campal dentate gyrus(DG)impairing the spatial learning and memory of Alzheimer disease(AD)rats.METHODS:Three-month-old male SD rats were randomly divided into control group and AD group.The rats in AD group received in-tracerebroventricular injection of streptozotocin(2.4 mg/kg)once combined with intraperitoneal injection of D-galactose(60 mg·kg^(−1)·d^(−1))for 6 weeks,while those in control group were given normal saline by the same way.The spatial learning and memory abilities of the rats were detected by Morris water maze.The ultrastructure of hippicampal DG was observed under transmission electron microscope.The protein levels of glucose-regulated protein 78(GRP78),protein kinase R-like endoplasmic reticulum kinase(PERK),Ca^(2+)/calmodulin-dependent protein kinase II(CaMKII),extracellular signal-regulated kinase(ERK)and brain-derived neurotrophic factor(BDNF)were measure by Western blot.The possible in-volvement of ERS in the DG in spatial learning and memory impairment in AD rats was examined by intraperitoneal injec-tion of 4-phenylbutyric acid(4-PBA;ERS inhibitor)and PD98059(inhibitor of ERK signaling pathway).RESULTS:Compared with the control rats,damaged synaptic structure,rough endoplasmic reticulum disarrangement and increased free ribosomes were observed,and the protein levels of ERS key molecules GRP78 and p-PERK were significantly in-creased in hippocampal DG of the AD rats(P<0.05).Compared with the control rats,the abilities of spatial learning and memory were significantly decreased(P<0.05),and the protein levels of p-CaMKII,p-ERK and BDNF in the DG were significantly reduced in the AD rats(P<0.05).In AD rats,4-PBA attenuated the spatial learning and memory impairment and significantly increased the protein levels of p-CaMKII,p-ERK and BDNF in the DG(P<0.05).Furthermore,inhibi-tion of ERK pathway by PD98059 reversed the effect of 4-PBA on the BDNF expression in DG of the AD rats(P<0.05).CONCLUSION:The ERS

关 键 词：齿状回 内质网应激 阿尔茨海默病 学习 记忆 CaMKII/ERK/BDNF信号通路 

分 类 号：R749.16[医药卫生—神经病学与精神病学] R363.2[医药卫生—临床医学]