摘要
目的观察慢性氟中毒大鼠脑组织中分裂原激活的蛋白激酶（MAPK）信号转导系统细胞外调节蛋白激酶（ERKI／2）的表达与活性，及其与学习记忆能力改变之间的关系，从而进一步探讨氟中毒神经系统损害的发病机制。方法72只SD大鼠按性别和体质量随机分为3组，每组24只。对照组：自由饮用自来水．含氟量低于0．5mg／L；低剂量染氟组：饮水含氟量为5．0mg／L；高剂量染氟组：饮水含氟量为50．0mg／L。实验6个月后，取大鼠脑组织，用蛋白印迹方法检测细胞外ERKI／2的蛋白表达与活性：用逆转录一聚合酶链反应（RT—PCR）方法测定ERKl／2的mRNA水平；用Morris水迷宫检测大鼠学习记忆能力改变。结果对照组、低、高剂量染氟组的ERKI／2蛋白水平分别为0．94±0．10、1．25±0．02、1．95±0．07，任意两组间比较．差异均有统计学意义（P〈0．05）；对照组、低、高剂量染氟组的phospho—ERKl／2蛋白水平分别为0．73±0．08、0．77±O．07、1．28±0．11，任意两组间比较，差异有统计学意义（P〈0．05）；低、高剂量染氟组的ERKl／2活化率『（68．4±3．8）％、（64．1±3．2）％]低于对照组[（823±10．7）％]，组间比较差异均有统计学意义（P〈O．05）；在第2、3、5、6天，低剂量染氟组的大鼠逃避潜伏期[（46．0±8．0）、（24．0±2．7）、（8．9±5．3）、（7．4±4．1）S]长于对照组『（39-3±6．9）、（19．1±9．1）、（8.3±3．4）、（4．8±2．7）S]，组间比较差异均有统计学意义（P〈0．05），高剂量染氟组的大鼠逃避潜伏期[（36．9±16．8）、（37．7±12．9）、（19．7±7．6）、（12．2±5．7）s]也长于对照组（P〈0．05），第3、5、6天，高剂量染氟组的大鼠逃避潜伏期长于低剂量染氟组（P〈0．05）；低剂量组、高剂量染氟组的大鼠第1次穿越平台位置时间[（1．17±0．75），（4．18±1．10）s]长于对照组[（5．89±0．56）S]，组间比较差异均有统计学意义（P〈0．05），低、高剂量染氟组的大鼠在原平台所在象限逗留时间[（17．05±4．25）、（18．20±4．57）S]短于对照组『（25．37±5．65）S]，组间比较差异均有统计学意义（P〈0．05）；大鼠脑组织中ERK1／2的活化率与空间探索实验第1次到达平台区域时间呈正相关（r=0．364，P〈0．05），与第6天定向航行实验找到平台时间呈正相关（r=0．497．P〈0．05）。结论慢性氟中毒导致大鼠脑组织中ERK1／2蛋白表达水平及活性改变，与慢性氟中毒大鼠学习记忆能力的降低有一定关系。
Objective To investigate the expression of extracellular signal-regulated protein kinase （ERK1/2） pathway in rat brains with fluorosis and the effects of fluoride on learning and memory of the rats, and to reveal the mechanisms of damaged nervous system resulted from the toxicity of the ion. Methods Seventy-two SD rats were divided into 3 groups and 24 rats were in each group. Three groups were fed respectively with different concentrations of fluoride （ NaF ） for 6 months to establish rat models with fluorosis. Controls were fed with tap water （NaF 〈 0.5 rag/L） ; lower and higher concentration group were fed with water containing NaF（5, 50 mg/L）. Animals are sacrificed after 6 months of treatment with fluoride and the dissected brains were kept for analysis. The protein levels of ERK1/2 in rat brains were detected by Western-blotting and the mRNA level by RT-PCR. The spatial learning and memorizing ability was measured by Morris water maze test. Results The ERK1/2 protein in control group, lower and higher concentration group was 0.944 ± 0.10, 1.253 ± 0.02,1.953 ± 0.07, the differece being statistically sighificant between any two groups （P 〈 0.05）. The phospho-ERK1/2 protein in control group, lower and higher concentration group was 0.73 ± 0.08,0.77 ± 0.07,1.28 ± 0.11, the differece being statistically sighificant between any two groups（P 〈 0.05）; the activation rate of phospho-ERK1/2 in lower and higher concentration group [ （68.4 ± 3.8）%, （64.1 ± 3.2）% ] was decreased compared to control group [ （82.3 ± 10.7）%], the d iffereee being signifieant（P 〈 0.05）. In the navigation trial, longer escape lateneies of lower concentration group on the second, the third, the fifth and the sixth day were observed[ （46.0 ± 8.0）, （24.0 ± 2.7）, （8.9 ± 5.3）, （7.4 ± 4.1 ）s] compared to the control[ （39.3 ± 6.9）, （19.1 ± 9.1 ）, （8.3 ± 3.4）, （4.8 ± 2.7）s], the differeee being significant （P 〈 0.05 or 〈 0.01 ） ; the similar results were also observed in the higher concentration group [ （36.9 ± 16.8）, （37.7 ± 12.9）, （19.7 ± 7.6）, （12.2 ± 5.7）s], and the escape lateneies of the higher concentration group on the third, the fifth and the sixth day were longer than that in lower concentration group. In the probe test, the rats took more time to reach the first cross in lower and higher concentration group[（1.17 ± 0.75）, （4.18 ± 1.10）s] than control group[（5.89 ± 0.56）sl, the differeee being significant （P 〈 0.05 or 〈 0.01 ） ; stayed shorter[ （ 17.05 ± 4.25 ）, （ 18.20 ± 4.57 ） s ] than control [ （25.37 ± 5.65）s ] in platform area （P 〈 0.01）; the activation rates of ERK1/2 were directly correlated with the time taken to reach the first cross platform located in the probe test（r = 0.364, P 〈 0.05） and the activation rates were also directly correlated with the escape latencies on the sixth day（r = 0.497, P 〈 0.05）, Conclusion Long-term exposure of excessive fluoride induces the change of expression and activating rate of the ERK1/2 in rat brains, leading to the decreased capacity of learning and memory.
出处
《中国地方病学杂志》
CAS
CSCD
北大核心
2009年第1期32-35,共4页
Chinese Jouranl of Endemiology
基金
基金项目：科技部97项目（2006CB708513）
国家自然科学基金（30760224）
贵州省科技厅项目[黔科合外G字（2006400107）、黔省专合字（2006）52、黔科合重大专项（2006）6015]
关键词
氟化物中毒
学习
记忆
细胞外调节蛋白激酶
Fluoride poisoning
Learning
Memory
Extraeellular signal-regulated protein kinase
