海马CRHR1调节慢性应激致老年前期小鼠学习记忆损伤的机制  

Mechanism of hippocampal CRHR1 regulating chronic stress-induced learning and memory impairment in early aged mice

作　　者：屠心茹 徐家雯 刘锐 陆雨琳 王书 姚余有 Tu Xinru;Xu Jiawen;Liu Rui;Lu Yulin;Wang Shu;Yao Yuyou(Dept of Health Inspection and Quarantine,School of Public Health,Anhui Medical University,Hefei 230032;The First Clinical Medical College,Anhui Medical University,Hefei 230032;Dept of Geriatrics,The Third Affiliated Hospital of Anhui Medical University,Hefei 230061;Anhui Provincial Key Laboratory of Population Health and Eugenics,Hefei 230032)

机构地区：[1]安徽医科大学公共卫生学院卫生检验与检疫学系,合肥230032 [2]安徽医科大学第一临床医学院,合肥230032 [3]安徽医科大学第三附属医院老年医学科,合肥230061 [4]人口健康与优生安徽省重点实验室,合肥230032

出　　处：《安徽医科大学学报》2024年第1期117-126,共10页Acta Universitatis Medicinalis Anhui

基　　金：国家自然科学基金(编号:81773452);安徽医科大学第三附属医院基础与临床合作提升计划培育专项(编号:安徽医科大学处室文件科字〔2022〕6号)。

摘　　要：目的探究海马促肾上腺皮质激素释放激素(CRH)受体1型(CRHR1)在慢性应激致老年前期小鼠学习记忆损伤中的作用机制。方法12~14月龄的C57BL/6J小鼠根据性别、基因型以及是否予以慢性不可预测应激(CUS)进行分组,对应激组施加为期30 d的CUS。使用聚合酶链式反应(PCR)、琼脂糖凝胶电泳和实时荧光定量PCR(RT-qPCR)对小鼠进行基因型鉴定。新物体识别实验和Morris水迷宫测定学习记忆能力。Golgi-Cox染色观察海马神经元树突受损情况,Western blot测定海马组织雷帕霉素靶蛋白(mTOR)、p-mTOR(Ser2448)、核糖体蛋白S6激酶(p70S6K)、p-p70S6K(Thr389/Thr412)蛋白表达,ELISA检测血清CRH水平。结果相较于慢性应激前,WT应激各组小鼠慢性应激后的认知系数下降,差异有统计学意义(P<0.05),而KN应激各组小鼠慢性应激前后认知系数差异无统计学意义。与WT应激组相比,WT对照组小鼠逃避潜伏期均缩短(P<0.05)、穿越平台和目标象限次数上升(P<0.01),KN各组小鼠上述差异无统计学意义。相较于WT对照组,WT应激组小鼠海马CA1、CA3、DG区神经元复杂性降低(P<0.05),海马p-mTOR、p-p70S6K表达水平均降低(P<0.05);而KN应激组与KN对照组相比,除雌性组小鼠海马p-mTOR表达水平降低外(P<0.05),其余均无显著性差异。此外,与对照组相比,应激各组小鼠血清CRH水平均上升,差异有统计学意义(P<0.01)。结论海马CRHR1调控慢性应激所致的老年前期小鼠的学习记忆损伤和神经元树突受损,其机制可能是慢性应激引起的高水平CRH无法与受体CRHR1结合,减轻了高水平CRH所抑制的mTOR/p70S6K信号通路表达。Objective To explore the mechanism of hippocampal corticotropin-releasing hormone(CRH)receptor type 1(CRHR1)in chronic stress-induced learning and memory impairment in early aged mice.Methods C57BL/6J mice aged 12-14 months were divided into two groups according to gender,and then divided into wild type(WT)group and hippocampal CRHR1 conditional gene knockout(KN)group according to genotype.Mice in each group were randomly divided into control group and stress group,and the stress group was subjected to chronic unpredictable stress(CUS)for 30 days.Genotyping of mice was performed using polymerase chain reaction(PCR),agarose gel electrophoresis and real-time fluorescence quantitative PCR(RT-qPCR).The new object recognition experiment and Morris Water maze measured learning and memory ability.Golgi-Cox staining was used to observe damage to hippocampal neuronal dendrites.The protein expressions of target protein of rapamycin(mTOR),p-mTOR(Ser2448),ribosomal protein S6 kinase(p70S6K)and p-p70S6K(Thr389/Thr412)were detected by Western blot.Serum levels of corticotropin releasing hormone(CRH)were measured by ELISA.Results Compared to mice without chronic stress,the cognitive coefficient of WT stress groups decreased after chronic stress,and the difference was statistically significant(P<0.05),while there was no significant difference in cognitive coefficient of KN stress groups before and after chronic stress.Compared with the WT stress group,the escape latency of the WT control group was shortened(P<0.05),and the number of crossing the platform and target quadrant increased(P<0.01),and there was no significant difference in the KN groups above.Compared with the WT control group,the WT stress group had a significant reduction in the neuronal complexity in the hippocampal CA1,CA3 and DG regions(P<0.05)and significant reductions in the expression of p-mTOR and p-p70S6K in the hippocampus(P<0.05).There was no significant difference in the expression of p-mTOR between the KN stress group and the KN control group(P>0.05),exc

关 键 词：慢性应激 学习记忆损伤 CRHR1 P-MTOR p-p70S6K 

分 类 号：R749.16[医药卫生—神经病学与精神病学]