慢性氟暴露对子二代大鼠空间学习记忆能力和海马PI3K/Akt/mTOR信号通路的影响  

Effects of chronic fluoride exposure on spatial learning and memory and hippocampal PI3K/Akt/mTOR signaling pathway in second offspring rats

作　　者：赵辰飞 安丽[1,2] 葛宇 谢春[1] Zhao Chenfei;An Li;Ge Yu;Xie Chun(The Key Laboratory of Ministry of Education for Environmental Pollution Monitoring and Disease Control,School of Public Health,Guizhou Medical University,Guiyang 550025,China;Guizhou Medical University,Guiyang 550025,China)

机构地区：[1]贵州医科大学公共卫生与健康学院,环境污染与疾病监控教育部重点实验室,贵阳550025 [2]贵州医科大学,贵阳550025

出　　处：《中华地方病学杂志》2023年第11期861-867,共7页Chinese Journal of Endemiology

基　　金：国家自然科学基金(81860563);贵州省2020年大学生创新创业训练计划项目(S202010660043)。

摘　　要：目的探讨慢性氟暴露对子二代(F2代)大鼠空间学习记忆及海马磷脂酰肌醇3-激酶(PI3K)、蛋白激酶B(Akt)、哺乳动物雷帕霉素靶蛋白(mTOR)表达的影响。方法将16只清洁级健康SD孕鼠按体质量[(200±50)g]采用随机数字表法分为4组:对照组[0 mg/L氟化钠(NaF)],低、中、高氟组(60、120、240 mg/L NaF),每组4只。母鼠自妊娠第0天至子一代(F1代)大鼠出生第21天(PND21)自由饮水染氟;F1代大鼠按同组母鼠染氟剂量继续染氟至出生第90天(PND90),各组选取6只(雌雄比为2∶1)合笼,雌性F1代大鼠持续染氟至F2代大鼠PND21;每组选取8只F2代大鼠(雌雄各4只,同窝别雌雄比为1∶1),染氟至PND90。F2代大鼠处死前,采用Morris水迷宫实验检测空间学习记忆能力;处死后,采用实时荧光定量PCR(qRT-PCR)和蛋白质印迹法(Western blot)分别检测海马PI3K、Akt、mTOR的mRNA和蛋白表达水平。结果与对照组第2~4天[(46.72±4.24)、(24.87±3.15)、(14.10±2.52)s]比较,中、高氟组F2代大鼠逃避潜伏期在第2天[(53.96±3.45)、(54.48±6.20)s]和第4天[(19.47±2.51)、(25.02±3.86)s],低、中、高氟组在第3天[(32.37±4.56)、(37.32±4.65)、(41.79±7.08)s]均延长(均P<0.05);与对照组比较,高氟组F2代大鼠首次达台时间延长,中、高氟组穿越平台次数均减少(均P<0.05)。除低氟组mTOR mRNA表达水平外,其余各染氟组大鼠海马PI3K、Akt、mTOR的mRNA和蛋白表达水平均低于对照组(均P<0.05)。相关性分析结果显示,NaF浓度与F2代大鼠第1~4天的逃避潜伏期及首次达台时间均呈正相关(r=0.44、0.57、0.79、0.80、0.58,均P<0.05);NaF浓度与F2代大鼠海马PI3K、Akt、mTOR的mRNA和蛋白表达水平及穿越平台次数均呈负相关(r=-0.71、-0.67、-0.73、-0.61、-0.58、-0.71、-0.82,均P<0.05)。结论慢性氟暴露可导致F2代大鼠空间学习记忆能力下降,其作用机制可能与抑制海马PI3K/Akt/mTOR信号通路有关。Objective To study the effects of chronic fluoride exposure on spatial learning and memory and the expression of phosphatidylinositol 3-kinase(PI3K),protein kinase B(Akt),and mammalian target of rapamycin(mTOR)in hippocampus of second offspring(F2 generation)rats.Methods Sixteen clean-grade healthy SD pregnant rats were randomly divided into four groups according to their body mass[(200±50)g]using a random number table method:the control group[0 mg/L sodium fluoride(NaF)],and the low,medium,and high fluoride groups(60,120,240 mg/L NaF),with four rats in each group.Fluoride exposure was carried out from the 0th day of pregnancy to the 21st day of birth(PND21)of first offspring(F1 generation)rats through free drinking water.The F1 generation rats continued to be exposed to fluoride at the same dose and method as the female rats in the same group until the 90th day of birth(PND90).Six rats(male to female ratio 2∶1)were selected from each group and housed together.Female F1 were continuously exposed with the same method until PND21 of the F2 generation rats.Eight F2 generation rats(4 males and 4 females,with a male to female ratio of 1∶1 in the same litter)were randomly selected from each group and exposed to NaF with corresponding concentrations from PND22 to PND90.Before the execution of F2 generation rats,Morris water maze experiment was used to examine spatial learning and memory ability.After execution,real-time fluorescence quantitative PCR(qRT-PCR)and Western blotting were used to detect the mRNA and protein expression levels of PI3K,Akt,and mTOR in the hippocampus,respectively.Results Compared with the control group days 2-4[(46.72±4.24),(24.87±3.15),(14.10±2.52)s],the escape latency of F2 generation rats was prolonged in the medium and high fluoride groups on the second day[(53.96±3.45),(54.48±6.20)s]and on the fourth day[(19.47±2.51),(25.02±3.86)s],and in the low,medium and high fluoride groups on the third day[(32.37±4.56),(37.32±4.65),(41.79±7.08)s,P<0.05].Compared with the control group,th

关 键 词：氟 海马 学习记忆 磷脂酰肌醇3-激酶 蛋白激酶B 哺乳动物雷帕霉素靶蛋白 

分 类 号：R114[医药卫生—卫生毒理学]