摘要
目的观察砷暴露对大鼠学习记忆能力和海马C-Jun表达影响,探讨砷致学习记忆损害机制。方法采用40只清洁级SD大鼠(体重:100±20 g),随机分为4组,每组10只,雌雄各半。以自由饮水方式染砷100 d,染砷组分别为:2.4,12和60 mg/L亚砷酸钠水溶液,对照组饮蒸馏水。采用Morris水迷宫实验评估大鼠学习和记忆能力,电感耦合等离子体发射光谱法(ICP-AES)测定脑总砷含量,实时荧光定量(q RT-PCR)测定海马C-Jun mRNA表达,免疫组化法检测Jun蛋白水平。结果染砷组脑砷含量高于对照组(P<0.05)。定位航行实验:染砷组与对照组比较,染砷组大鼠逃逸潜伏期延长,从游泳训练第三天结果发现,高剂量组大鼠潜伏期与对照组和低剂量组差异有统计学意义(P<0.05),该差异延续到第四天。空间探索实验:随着染砷浓度增加,染砷组大鼠在原平台象限停留时间缩短(P<0.05)、游泳距离减少(P<0.05),穿越平台次数依次减少(P<0.05)。C-Jun蛋白表达随染砷剂量增加而增加(P<0.05),而C-Jun mRNA表达染砷组较对照组下降(P<0.05)。结论亚慢性砷暴露可引起Jun蛋白过度表达,C-Jun mRNA表达下调,学习记忆能力降低,C-Jun表达异常是长期砷暴露致学习记忆能力下降重要中间环节之一。
Objectives To observe the effects of arsenic exposure on learning and memory ability and the expression of C-Jun in the hippocampus of rats,in order to investigate the mechanism of learning and memory injury from arsenic exposure. Methods Forty SD rats（ weight： 100 ± 20 g; half in male and female） were randomly divided into four groups,10 rats in each group. The concentration of sodium arsenite in drinking water was 0,2. 4,12 and 60 mg / L for each group for 100 days. Morris water maze was used for the evaluation of learning and memory ability. The level of arsenic in brain was detected with ICP-OES. The expression of C-Jun mRNA in hippocampus was measured by q RT-PCR technique. The expression of Jun protein in hippocampus was observed by immunohistochemistry. Results Arsenic level in the brain of arsenic exposure groups was significantly higher than the control group（ P 〈0. 05）. The latent time to find out the hidden platform in a place navigation test was longer in arsenic exposure groups than that in the control group,the latent time was longer with the increase of arsenic dosage and the effect lasted until the fourth day of the test（ P〈 0. 05）. In spatial probe test,the time for standing in the quadrant of original platform in arsenic exposure groups was shorter（ P〈 0. 05）,the swimming distance to the quadrant of original platform and the frequency of crossing original platform was less in exposure groups（ P 〈0. 05）. The expression of C-Jun protein was higher with the increase of arsenic dosage（ P 〈0. 05）,whereas the level of C-Jun mRNA in high dose group was lower compared with the control group（ P〈 0. 05）. Conclusions Sub-chronic arsenic exposure could induce an excessive expression of Jun protein,whereas the level of C-Jun mRNA was downregulated and the learning and memory ability was reduced. The abnormity of C-Jun expression might be one of important intermediate links in the injury of learning and memory ability.
出处
《环境卫生学杂志》
2016年第1期1-5,共5页
JOURNAL OF ENVIRONMENTAL HYGIENE
基金
贵州省优秀科技教育人才省长专项资金项目(黔省专合字【2012】42号)
