孕哺期至成年前持续氟染毒对子鼠空间学习记忆和海马病理改变及miR-204、miR-34b-5P表达的影响  

Effects of continuous fluoride exposure from pregnancy to adulthood on spatial learning and memory,hippocampal pathological changes,and expressions of miR-204 and miR-34b-5P in offspring rats

作　　者：李阳 谢春 张玥 张华 LI Yang;XIE Chun;ZHANG Yue;ZHANG Hua(School of Public Health,the Key Laboratory of Environmental Pollution Monitoring and Disease Control,Ministry of Education,School of Basic Medical Sciences,Guizhou Medical University,Guiyang,Guizhou 550025,China;Department of Pharmacology,School of Basic Medical Sciences,Guizhou Medical University,Guiyang,Guizhou 550025,China)

机构地区：[1]贵州医科大学公共卫生学院,环境污染与疾病监控教育部重点实验室,贵州贵阳550025 [2]贵州医科大学基础医学院药理学教研室,贵州贵阳550025

出　　处：《环境与职业医学》2020年第12期1175-1181,共7页Journal of Environmental and Occupational Medicine

基　　金：国家自然科学基金项目(81860563);贵州省科技支撑计划(黔科合支撑[2018]2753);贵州省区域内一流学科建设项目—公共卫生与预防医学(黔教科研发2017[85]号)。

摘　　要：[背景]过量氟可蓄积于脑组织并导致神经系统损伤。微小RNA(miRNA)可通过调控相关蛋白表达,影响学习记忆功能发挥。[目的]探讨孕哺期至成年前氟暴露对子鼠空间学习记忆和海马中miR-204、miR-34b-5P表达的影响。[方法]16只清洁级健康SD孕鼠随机分为4组,每组4只,自由饮水染毒,各组饮水中氟化钠质量浓度(后称浓度)分别为0、60、120、240 mg·L^(-1)。母鼠从妊娠第0天~子鼠出生的第21天(PND21)染毒;各组随机选8只子鼠(雌雄各4只,同一窝别雌雄比为1∶1)在PND22~PND90进行染毒。采用Morris水迷宫实验检测空间学习记忆能力。子鼠处死前收集24 h尿液,心脏采血后处死,测定尿、脑及血清氟,光镜观察海马组织病理变化;分离海马组织保存于-80℃,实时荧光定量PCR检测海马组织中miR-204、miR-34b-5P表达水平。[结果]除出生第6周低氟组外,各染毒组大鼠体重均低于对照组(P<0.05)。Morris水迷宫显示:第2、3、4天子鼠逃避潜伏期与氟化钠的染毒浓度呈正相关(r=0.443、0.519、0.840;均P<0.05);子鼠首次到达平台时间及穿越平台次数分别与氟化钠染毒浓度呈正相关与负相关(r=0.828、-0.599;均P<0.001)。60、120、240 mg·L^(-1)染毒组尿氟浓度分别为(13.08±1.60)、(14.49±1.17)、(25.92±2.38)mg·L^(-1),较对照组[(3.89±0.52)mg·L^(-1)]升高(P<0.001);各染毒组脑氟水平分别(8.20±0.68)、(16.03±0.84)、(25.39±0.62)μg·g^(-1),较对照组(1.28±0.11)μg·g^(-1)升高(P<0.001);各染毒组血清氟浓度分别为(0.04±0.00)、(0.06±0.01)、(0.16±0.12)mg·L^(-1),较对照组[(0.02±0.00)mg·L^(-1)]升高(P<0.001);染毒组子鼠尿、脑及血清氟水平均与氟化钠浓度呈正相关(r=0.948、0.996、0.914;均P<0.001)。HE染色结果显示:与对照组比较,染毒组出现海马神经元体积形态缩小,胞质颜色红染,细胞核固缩,染色加深,结构模糊和核仁消失等病理改变。中、高氟组中miR-204与各染毒组中miR-34b-5P表[Background]Excessive fluoride can accumulate in brain tissues,causing nervous system damage.Micro RNA(miRNA)can affect the ability of learning and memory by regulating the expressions of related proteins.[Objective]This experiment explores the effects of fluoride exposure from pregnancy to adulthood on spatial learning and memory of offspring and the expressions of miR-204 and miR-34 b-5 P in the hippocampus.[Methods]Sixteen pregnant SD rats were randomly divided into four groups and exposed to NaF via drinking water at 0,60,120,and 240 mg·L^(-1),respectively,with four rats in each group.The pregnant rats were treated from pregnant day 0 to postnatal day 21(PND21)of the offspring rats.From PND22 to PND90(adulthood),8 offspring rats(4 males and 4 females,and litter sex ratio was 1:1)from each group were treated with the same concentrations of NaF as the dams through the same procedure.The offspring rats were tested in the Morris water maze.Before death,24 h urine was collected,and blood was collected by heart puncture.Urinary,brain,and serum fluoride concentrations were determined;the pathological changes of hippocampus were observed under a light microscope;the separated hippocampus were stored at-80℃and tested for miR-204 and miR-34 b-5 P expression levels by real-time PCR.[Results]Compared with the control group,the body weight of each exposure group was significantly reduced(P<0.05),except the low fluoride exposure group at postnatal week 6.The Morris water maze results showed that on the second,third,and fourth days of training,the escape latency was positively correlated with fluoride exposure concentration(r=0.443,0.519,0.840;P<0.05);the first arriving time and the number of crossing the platform were positively and negatively correlated with fluoride exposure concentration respectively(r=0.828,-0.599;P<0.001).The urinary fluoride concentrations of the 60,120,and 240 mg·L^(-1)exposure groups were(13.08±1.60),(14.49±1.17),and(25.92±2.38)mg·L^(-1),respectively,significantly higher than that of the co

关 键 词：氟 海马 学习记忆 微小RNA miR-204 miR-34b-5P 

分 类 号：R114[医药卫生—卫生毒理学]