高碘致发育期大鼠学习记忆能力及海马神经组织凋亡的影响  

Effects of high iodine exposure on learning and memory ability and apoptosis of hippocampal neurons in developing rats

作　　者：高童宁 张祖山 崔玉山[2] 赵亮[2] 张斌 虞静雯 郭百慧 刘洪亮 GAO Tong-ning;ZHANG Zu-shan;CUI Yu-shan;ZHAO Liang;ZHANG Bin;YU Jing-wen;GUO Bai-hui;LIU Hong-liang(College of Public Health,Tianjin Medical University,Tianjin 300070,China;不详)

机构地区：[1]天津医科大学公共卫生学院,天津300070 [2]天津市疾病预防控制中心环境与健康室 [3]天津市卫生计生综合监督所

出　　处：《环境与健康杂志》2019年第11期962-966,共5页Journal of Environment and Health

基　　金：国家自然科学基金(81573107,81372934)。

摘　　要：目的探讨饮用水高碘对大鼠学习能力及海马神经组织凋亡功能的影响。方法将24只SPF级成年SD孕鼠随机分为4组,分别为对照组(饮用自来水)及500、2500、5000μg/L碘酸钾暴露组,采用自由饮水方式进行高碘暴露,连续暴露21 d。随机从各剂量组选择断乳雌、雄仔鼠各10只,延用相同剂量进行暴露直至第4个月末。应用Morris水迷宫实验评价大鼠学习记忆能力,采用RT-PCR法检测大鼠海马组织Bcl-2、Caspase-3和Cyt C mRNA的表达水平,采用Western Blot法检测大鼠海马神经组织Bcl-2、Caspase-3和Cyt C蛋白的表达水平。结果与对照组相比,5000μg/L碘酸钾暴露组雄性大鼠训练不同时间内的平台潜伏期均延长,而2500μg/L碘酸钾暴露组雌性大鼠仅训练第2天时的平台潜伏期延长,差异均有统计学意义(P<0.05)。与对照组相比,各浓度碘酸钾暴露组大鼠穿越平台的次数均下降,差异有统计学意义(P<0.05);而空间探索时间、路径比例均无明显变化。随着碘酸钾暴露浓度的升高,雄性大鼠穿越平台次数呈下降趋势。与对照组相比,2500μg/L碘酸钾暴露组大鼠海马神经细胞Caspase-3基因表达水平升高,差异有统计学意义(P<0.05);而各浓度碘酸钾暴露组大鼠海马神经细胞Bcl-2、Cyt C基因的表达水平均无明显改变。与对照组相比,2500、5000μg/L碘酸钾暴露组大鼠海马神经细胞Cyt C和Caspase-3蛋白的表达水平均升高,Bcl-2蛋白的表达水平均降低,差异有统计学意义(P<0.05);与500μg/L碘酸钾暴露组相比,5000μg/L碘酸钾暴露组雄性大鼠海马神经细胞Cyt C和Caspase-3蛋白的表达水平升高,差异均有统计学意义(P<0.05)。结论高碘暴露可造成4月龄大鼠空间学习和记忆能力的下降,可能与海马神经细胞发生凋亡有关。Objective To understand the effects of high iodine intake through drinking water on learning ability and apoptotic function of hippocampal neural tissue in rats.Methods A total of 24 healthy pregnant SD rats were randomly divided into four dose groups,the control group(tap water),500,2500,and 5000μg/L potassium iodate exposure groups which were exposed to high iodine through drinking water for 21 days.In each potassium iodate exposure group,ten weaned female infant rats and ten weaned male infant rats were randomly selected to be exposed at the same dose of iodate until the end of the fourth month.Morris water maze test was used to evaluate the learning and memory ability.The expression levels of Bcl-2,caspase-3 and Cyt C mRNA in hippocampus were measured by RT-PCR.The expression of Bcl-2,Caspase-3 and Cyt C proteins in hippocampal neural tissue were detected by the Western blot method.Results Compared with the control group,the latency of escaping onto platform of male rats in the 5000μg/L potassium iodate group was prolonged,while that of the female rats in the2500μg/L potassium iodate group was prolonged only on the second day of training,with significant differences(P<0.05).Compared with the control group,the times of rats crossing the platform in each potassium iodate exposure group decreased significantly(P<0.05),with a dose dependent manner in male rats,and no significant change was seen in space exploration time or path selection.Compared with the control group,the expression level of Caspase-3 gene in hippocampal neurons in2500μg/L potassium iodate group increased significantly(P<0.05),while the expression levels of Bcl-2 and Cyt C genes in hippocampal neurons in potassium iodate exposure group had no significant change.Compared with the control group,the expression levels of Cyt C and Caspase-3 proteins in hippocampal neurons in 2500,5000μg/L potassium iodate groups increased,and the expression levels of Bcl-2 protein decreased significantly(P<0.05).Compared with the 500μg/L potassium iodate group

关 键 词：高碘 饮用水 学习和记忆能力 细胞凋亡 

分 类 号：K994.6[历史地理—人文地理学]