饲料锌过量对幼鼠脑发育及学习记忆的影响及其机理探讨  

Effects of Excessive Zinc in Fodder on Brain Development and Abilities of Learning and Memory and Their Mechanisms in Young Rats

作　　者：孔祥英[1] 刘力建[1] 盛锡联[1] 任榕娜[1] 白家肆 

机构地区：[1]第三军医大学西南医院儿科

出　　处：《中华预防医学杂志》1998年第4期225-228,共4页Chinese Journal of Preventive Medicine

摘　　要：目的观察锌过量对幼鼠脑发育和学习记忆行为的影响。方法从哺乳期开始建立过量锌幼鼠模型，采用电镜观察、神经生化和神经行为观察等方法。结果随饲料锌含量的增加幼鼠大脑及海马重量减少，血清及海马锌增高。过量锌１、２组（ＺＥ１、ＺＥ２组）幼鼠主动回避反应（ＡＡＲ）习得率及活动明显低于自由喂养组（ＡＬ组）及ＺＥ２组的配对组（ＰＦ组），ＺＥ２组的恢复组（ＺＥ２Ｒ组）ＡＡＲ习得率也明显低于ＡＬ和ＰＦ组，但明显高于ＺＥ２组。ＰＦ组与ＡＬ组ＡＡＲ习得率差异无显著性，但活动较ＡＬ组多。ＺＥ２组海马一氧化氮含量增加而生长抑素含量减少，脑组织兴奋性氨基酸和抑制性氨基酸总量增高，尤其是谷氨酸增高更为明显。ＺＥ２组海马ＣＡ１区神经元、胶质细胞及细胞器均有不同程度变性、坏死，突触小泡破裂。结论过量锌饲料明显影响幼鼠脑发育和功能。Objective To study the effects of excessive zinc in fodder on brian development and abilities of learning and memory and to explore their mechanisms in young rats. Methods Animal models with excessive zinc were established in young Wistar rats during their lactation period. Rats were divided into five groups, Groups ZE1 and ZE2 were fed with excessive zinc, Group AL was freely fed with Flanagna fomula fodder added with zinc sulfate, Group PF was matched pair of Group ZE2 and Group ZE2R was fed with fodder same as Group AL after weaning. Ultrastructure was observed with electron microscopy, their free amino acids, nitrous oxide and somatostatin were measured with neurobiochemical methods, and their abilities to learn and memorize were examined. Results Weight of cerebrum and hippocampus in the rats reduced and zinc levels in their serum and hippocampus raised with the increase of zinc content in their fodder. Acute avoidance response (AAR) and movement in the young rats fed with excessive zinc in Groups ZE1 and ZE2 were obviously lower than in Groups AL and PF. AAR was significantly lower in Group ZE2R than that in Groups AL and PF, but significantly higher than that in Group ZE2. There was no signifcant difference in AAR between Groups PF and AL, but more movement was observed in them. Nitrous oxide in hippocampus raised and somatostatin decreased in Group ZE2, and total amount of excitatory and inhibitory amino acids in brain tissues raised, especially for glutamic acid. Neurones, gliocytes and organella in the CA1 region of hippocampus in the Group ZE2 showed degeneration, necrosis and rupture of synaptic bolus to varied extent. Conclusion Excessive zinc in fodder could significantly affect brain development and functions in young rats with multiple mechanisms.

关 键 词：锌 脑发育 学习 记忆 脑功能 

分 类 号：R591.102[医药卫生—内科学] R151.2[医药卫生—临床医学]