全脑照射对幼鼠海马神经元树突棘形态及密度的影响  

Cranial irradiation alters dendritic spine density and morphology in the young rat hippocampus

作　　者：丁昕 吴昊昊 冀胜军 田野[4] Ding Xin;Wu Haohao;Ji Shengjun;Tian Ye(Department of Radiotherapy and Oncology,Affiliated Hospital of Xuzhou Medical University,Xuzhou 221000,China;Department of Radiotherapy and Oncology,Yancheng No.1 People's Hospital,Yancheng 224006,China;Department of Radiotherapy and Oncology,Nanjing Medical University Affiliated Suzhou Hospital,Suzhou 215002,China;Department of Radiotherapy and Oncology,Second Affiliated Hospital of Soochow University,Suzhou 215004,China)

机构地区：[1]徐州医科大学附属医院放疗科,221000 [2]盐城市第一人民医院放疗科,224006 [3]苏州市立医院放疗科,215002 [4]苏州大学第二附属医院放疗科,215004

出　　处：《中华放射医学与防护杂志》2021年第9期641-646,共6页Chinese Journal of Radiological Medicine and Protection

基　　金：国家自然科学基金(81773223);江苏省卫生健康委科研课题(H2018116);江苏省博士后课题(2018K259C)。

摘　　要：目的了解电离辐射对幼鼠海马齿状回(DG)区和CA1区树突棘形态及结构随时间变化的特点,为研究放射性认知功能障碍发生的分子机制提供详尽直接的形态学依据。方法给予21 d龄SD大鼠单次剂量10 Gy全脑照射,观察照射后1、3个月大鼠认知功能改变,海马DG区和CA1区中树突棘密度及形态学变化。Western blot检测电离辐射对突触后致密蛋白(PSD95)的影响。结果SD幼鼠在照射后3个月发生明显的学习和记忆力损伤。海马DG区树突棘密度显著降低,照射后1、3个月分别降低了39.06%、29.27%(t=14.96、12.35,P<0.05)。海马CA1区底树突的树突棘密度在照射后1个月降低了33.40%(t=10.39,P<0.05),而在照射后3个月其树突棘密度无明显变化;而CA1区顶树突的树突棘密度在照射后1、3个月均无明显变化。此外,海马DG区和CA1区树突棘形态处于动态变化的过程;突触后PSD95在照后1和3个月分别降低了24.6%和50.5%(t=2.97、9.27,P<0.05)。结论电离辐射后幼鼠海马不同脑区树突棘密度及形态学变化提示PSD95可能通过影响树突棘的结构形态降低突触可塑性,从而参与放射性认知功能障碍的发生。Objective To explore the changes of dendritic spine morphology and structure in dentate gyrus(DG)and CA1 areas of hippocampus of young rats,so as to provide a direct morphological basis for studying the molecular mechanism of radiation cognitive impairment.Methods 21-day-old Sprague-Dawley(SD)rats were given a single dose of 10 Gy whole brain irradiation.The changes of cognitive function,dendritic spine density and morphological changes in DG and CA1 areas of hippocampus were observed 1 and 3 months after irradiation,and the expression of postsynaptic density protein(PSD95)was detected by Western blot.Results The cognitive impairment was observed in young rats 3 months after irradiation.The density of dendritic spines in DG area of hippocampus was decreased significantly by 39.06% and 29.27% at 1 and 3 months after irradiation(t=14.96,12.35,P<0.05),respectively.The density of dendritic spines in the basal dendrites of hippocampal CA1 area was decreased by 33.40%(t=10.39,P<0.05)1 month after irradiation,but had no significant change at 3 months after irradiation.While the density of dendritic spines in the apical dendrites of CA1 region did not change significantly at 1 and 3 months after irradiation.In addition,the morphology of dendritic spines in DG and CA1 regions of hippocampus was dynamically changed after irradiation.The expression of PSD95 protein was decreased by 24.6% and 50.5%(t=2.97,9.27,P<0.05)at 1 and 3 months after irradiation,respectively.Conclusions This study reported the density and morphological changes of dendritic spines in different brain regions of hippocampus of young rats after ionizing radiation,suggesting that PSD95 may participate in the occurrence of radiation-induced cognitive impairment by affecting the structure and morphology of dendritic spines and reducing synaptic plasticity.

关 键 词：电离辐射 海马 树突棘 突触可塑性 突触后致密蛋白 

分 类 号：R730.55[医药卫生—肿瘤]