母鼠孕期慢性应激对子代学习记忆功能及海马脑源性神经营养因子表达的影响  

Effects of maternal chronic stress during pregnancy on learning and memory function and expression of hippocampal brain-derived neurotrophic factor in offspring rats

作　　者：付有娟 刘志宏 赵枫 关素珍 FU You-juan;LIU Zhi-hong;ZHAO Feng;GUAN Su-zhen(School of Public Health and Management,Ningxia Medical University,Yinchuan,Ningxia 750004,China)

机构地区：[1]宁夏医科大学公共卫生与管理学院,宁夏银川750004

出　　处：《环境与职业医学》2020年第3期267-273,共7页Journal of Environmental and Occupational Medicine

基　　金：国家自然科学基金地区基金项目(81960591);宁夏自然科学基金项目(2018AAC02007);2019年宁夏医科大学优势学科群建设项目(3);宁夏医科大学2019年校级大学生创新创业训练计划项目(14)。

摘　　要：[背景]孕期慢性应激刺激会对子代的生长发育产生长远的影响,其中最严重的损害是引起子代学习记忆能力下降。研究发现孕早期和孕晚期母源性应激对胎儿大脑发育的影响最明显,可引起海马组织中单胺类神经递质及胰岛素样生长因子Ⅱ表达异常,但突触相关蛋白脑源性神经营养因子(BDNF)的表达及其与学习记忆功能之间的关联较少报道。[目的]观察孕期慢性应激后子鼠学习记忆功能的变化,检测海马组织突触相关蛋白BDNF的表达情况,并分析其与子代学习记忆功能之间的关联。[方法]选择SPF级未曾受孕、80~90日龄的Wistar雌鼠20只,随机分为模型组和对照组,每组10只;SPF级90~100日龄的Wistar雄鼠15只,随机分为模型组10只和对照组5只。适应性饲养一周后,通过慢性不可预知温和应激(CUMS)建立母鼠孕期应激模型,模型组母鼠每天给予刺激,连续21 d不间断;对照组母鼠正常环境饲养。应激刺激开始的第3天,将模型组雌鼠与雄鼠按照1∶1合笼,对照组按2∶1合笼。母鼠应激前1 d和应激后1、7、14 d分别进行内眦静脉取血,采用125I皮质醇放射免疫试剂盒对血浆皮质醇的含量进行测定,根据公式计算皮质酮浓度,当模型组皮质酮浓度高于对照组表示建模成功。子鼠出生后21 d(记为PND21)时断乳,两组均从不同窝别中随机抽取16只子鼠(雌、雄各8只),分别为对照子鼠组和模型子鼠组,编号后每笼4只正常环境饲养。PND28时,测量子鼠体重。PND42时测量子鼠体重,利用Morris水迷宫(主要指标为逃避潜伏期和跨越平台次数)和Y迷宫(主要指标为达标所需训练的次数和正确反应率)对子代学习记忆能力进行测定,通过HE染色及电镜对子鼠海马组织形态学进行观察,采用实时荧光定量PCR法和Western blotting法测定海马组织突触相关蛋白BDNF mRNA和蛋白的表达水平。[结果]在应激第7天,模型组母鼠血浆皮质酮水平[Background] Chronic stress stimulation during pregnancy will have a long-term impact on the growth and development of offspring, and the most serious damage is the decline of learning and memory ability. Previous studies have found that maternal stress in early or late pregnancy has the most significant effect on the development of fetal brain, such as abnormal expressions of monoamine neurotransmitter and insulin-like growth factor Ⅱ in hippocampus, but there are few reports about the expression of brain derived neurotrophic factor(BDNF) and its relationship with learning and memory function.[Objective] This experiment is designed to observe the changes of learning and memory function in offspring of pregnant rats with chronic stress, detect the expression of BDNF in hippocampus, and analyze the relationship between BDNF and learning and memory of offspring rats. [Methods] Twenty female Wistar rats of SPF grade aged 80-90 days and not pregnant were randomly divided into a model group and a control group, with 10 rats in each group. Fifteen male Wistar rats of SPF grade aged 90-100 days were randomly divided into a model group with 10 rats and a control group with 5 rats. After one week of adaptive feeding, a stress model of female rats was established by chronic unpredictable mild stress(CUMS) for 21 consecutive days, while the female rats in the control group were fed in normal environment. On the 3 rd day of the stress stimulation, the female and male rats in the model group were caged according to 1∶1 sex ratio, and the control rats were caged according to 2∶1. One day before the stress and 1, 7, and 14 days after the stress, blood samples were collected from the angular vein of the female rats, plasma cortisol content was measured by 125 I cortisol radioimmunoassay, and the concentration of corticosterone was calculated. If the concentration of corticosterone in the model group was higher than that in the control group, the model was considered successful. On postnatal day 21(PND21), the offspring rat

关 键 词：孕期 慢性应激 子鼠 学习记忆 脑源性神经营养因子 

分 类 号：R114[医药卫生—卫生毒理学]