过表达脑红蛋白对AD转基因小鼠学习记忆能力、空间探索能力的影响及其机制

摘要

目的 观察侧脑室注射过表达脑红蛋白(pNGB)对阿尔茨海默病(AD)转基因小鼠学习记忆能力、空间探索能力的影响,并探讨其机制.方法 24只AD小鼠随机分为3组各8只,实验组小鼠侧脑室注射pCDNA3.1(1 μg/μL)+ pNGB(1 μg/μL),模型组注射生理盐水+pCDNA3.1(1μg/μL),对照组注射生理盐水,注射体积均为5 μL,每周1次,连续8周.采用Morris水迷宫实验评价小鼠学习记忆能力和空间探索能力,半胱氨酸蛋白酶(Caspase)-3、Caspase-9活性检测试剂盒检测脑组织Caspase-3、Caspase-9酶活性,Westem blotting法检测脑组织Caspase-3、Caspase-9蛋白.结果 与模型组、对照组比较,实验组第5天逃避潜伏期短(P均＜0.05);与模型组、对照组比较,实验组实验第6天穿越次数多,穿越距离、穿越时间长(P均＜0.05);与对照组比较,实验组Caspase-3、Caspase-9酶活性和蛋白表达降低(P均＜0.05).结论 侧脑室注射pNGB能明显改善AD转基因小鼠的学习记忆能力和空间探索能力,机制可能与其可抑制脑组织中Caspase-3、Caspase-9酶活性和蛋白表达有关.%Objective To observe the effects of intracerebroventricular injection of neuroglobin over-expression (NGB) on the learning and memorial ability and spatial exploration ability of Alzheimer's disease (AD) transgenic mice and to explore its potential mechanisms.Methods Twenty-four AD mice were randomly divided into three groups:The mice in the experimental group were given pCDNA3.1 (1 μg/μL) + pNGB (1 μg/μL) through intracerebroventricular injection,mice in the model group were injected with normal saline + pCDNA3.1 (1 μg/μL),and mice in the control group were injected with normal saline (5 μg/μL),once a week,for 8 weeks.Morris water mazc test was used to observe the learning and memory ability and the spatial exploration ability of mice.The activities of Caspase-3 and Caspase-9,and their protein expression were detected by Caspase-3 and Caspase-9 kits and Western blotting,respeetively.Results Compared with the model group and control group,the mice had shorter escape latency on the fifth day in the experimental group (P ＜ 0.05).Compared with the model group and the control group,mice in the experiment group had more crossings on the sixth day,and longer crossing distance and longer crossing time (all P ＜ 0.05).The activity and protein expression of Caspase-3 and Caspase-9 in brain tissues decreased in the experimental group as compared with those of the control group (both P ＜ 0.01).Conclusion Intracerebroventricular injection of pNGB could significantly improve the learning and memory ability and spatial exploration ability of AD transgenic mice by inhibiting the activity and protein expression of Caspase-3 and Caspase-9.