50Hz磁场长期暴露对大龄大鼠学习记忆及脂质过氧化反应的影响

Influences of long-term exposure to 50 Hz magnetic fields on learning and memory and lipid peroxidation reaction in old rats

目的 探讨长期0．1mT50Hz磁场暴露对大龄大鼠学习记忆及海马组织的超氧化物歧化酶（SOD）、Na^＋K^＋-ATP酶、Ca^2＋-Mg^2＋-ATP酶活性与丙二醛（MDA）水平的影响。方法应用Morris水迷宫方法测定动物的空间学习记忆能力；应用试剂盒分别测定SOD、Na^＋K^＋-ATP酶、Ca^2＋-Mg^2＋-ATP酶活性及MDA水平。结果10d0．1mT50Hz磁场暴露对大龄大鼠的学习记忆功能无明显影响。长期（4个月或8个月）0.1m T50Hz磁场暴露能使大鼠的逃避潜伏期明显延氐，穿环系数显著减少，表明大鼠的空间学习记忆能力受损。长期磁场暴露也使大龄大鼠海马组织及其线粒体的SOD活性降低，MDA水平升高，Na^＋K^＋-ATP酶、Ca^2＋-Mg^2＋-ATP酶活性降低。结论长期0．1mT50Hz磁场暴露可损伤大龄大鼠的学习记忆能力，此作用可能与其增强海马组织的脂质过氧化反应有关。

Objective To investigate the effect of long-terna exposure to 0.1 naT 50 Hz magnetic fields （MF） on the ability of learning and memory, and the activities of superoxide dismutase （ SOD）, Na^＋K^＋-ATPase、Ca^2＋-Mg^2＋-ATPase, and the malondialdehyde （MDA） level in hippocampus of old rats. Methods The changes in spatial learning and menaoly ability were examined by Morris water maze. The activities of SOD and ATPase and MDA level were determined by using commercially available kits. Results Acute （ 10 days） exposure to 0.1mT 50 Hz MF did not aftect the function of learning and memory in the old rats. However, after the old rats were exposed to 0.1 mT 50 Hz MF for 4 naonths or 8 months, the escape latency was obviously prolonged and the crossing annt,lus coefficient was reduced significantly, indicating that the spatial learning and memory function of old rats was damaged. Moreover, the activities of SOD,Na^＋K^＋-ATPase and Ca^2＋-Mg^2＋-ATP ase were considerably inhibited, anti the MDA level increased in hippocanapus tissue and its naitochondria. Conclusion Long-term exposure （4 months or 8 months） to 0. 1 mT 50 Hz MF can damage the old rats＇ spatial leaning and memory function, which may be associated with the increase in lipid peroxidation in the hippocanapus tissue.