锌对染铅大鼠海马胆囊收缩素阳性神经元的保护作用

目的　探讨锌对染铅大鼠海马胆囊收缩素 (CCK)神经元的保护作用及其与动物学习记忆功能变化的关系。方法　选用Wistar大鼠 36只 ,均分为对照组、染铅组和铅加锌组 ,后两组分别饮用6 .15mmol/L醋酸铅 ,铅加锌组同时补充 3.10mmol/L硫酸锌。利用反映学习记忆功能的Y迷宫法测试大鼠神经行为的改变 ;通过原子吸收法检测血清和海马铅含量 ;采用ABC免疫组化法结合图像分析法观测大鼠海马不同亚区CCK阳性神经元的变化。结果　染铅组大鼠血清和海马铅含量比铅锌组和对照组明显升高 ,差异有显著性 (P <0 .0 5 ) ,铅锌组与对照组之间的差异无显著性 (P >0 .0 5 )。染铅组大鼠学习记忆能力明显低于铅锌组和对照组 ,差异有显著性 (P <0 .0 5 ) ,而铅锌组和对照组的差异无显著性 (P >0 .0 5 )。免疫组化结果显示 ,染铅组大鼠海马CA1区和CA3 区CCK阳性神经元数目及其反应产物的积分光密度明显少于铅锌组和对照组 ,差异有显著性 (P <0 .0 5 ) ,铅锌组与对照组各亚区的差异均无显著性 (P >0 .0 5 )。结论　铅可损伤大鼠学习记忆能力和影响海马各区CCK阳性神经元的数目。锌对铅引起的学习记忆损伤和海马CCK阳性神经元的变化有保护作用.

Protection of zinc on hippocampal cholecystokinin of lead-exposed rat

OBJECTIVE: To investigate the relationship between the effects of zinc on hippocampal cholecystokinin (CCK) positive neurons and learning and memory ability of lead-exposed rats. METHODS: Thirty-six Wistar rats were divided into control group, lead-exposed group (drunk 6.15 mmol/L of lead solution) and lead-zinc group (drunk 6.15 mmol/L of lead + 3.10 mmol/L of ZnSO(4) solution) randomly. Y-maze test was used to study learning and memory ability in rats; Atomic absorption method was used to determine serum and hippocampal lead content; ABC immunohistochemistry and quantitative graphic analysis were used to investigate the changes of CCK positive neurons in different hippocampal subfields in lead-exposed rats. RESULTS: The learning and memory ability in lead-exposed rats were significantly lower (P < 0.05) while the serum and hippocampal lead content in lead-exposed rat were significantly higher (P < 0.05) than those in control and lead-zinc group. The number and optical density of CCK positive neurons in CA(1) and CA(3) areas of lead-exposed rats were significantly lower (P < 0.05) than those in control and lead-zinc group. No differences in these indexes between the control and lead-zinc group were found (P > 0.05). CONCLUSION: Lead may damage the learning and memory ability and affect the number of CCK positive neurons in lead-exposed rats. Zinc might play an important role in preventing lead-induced damages.