电针对异氟醚引起的APPswe/PS1 dE9小鼠学习记忆能力及海马激活型Caspase-3、Bcl-2/Bax变化的影响

Electroacupuncture Intervention Inhibits the Decline of Learning-memory Ability and Overexpression of Cleaved Caspase-3 and Bax in Hippocampus Induced by Isoflurane in APPswe/PS 1 dE 9 Mice

目的:探讨电针对异氟醚诱导的阿尔茨海默病神经毒性的调节机制。方法:将6月龄阿尔茨海默病APPswe/PS 1dE 9双转基因小鼠(AD小鼠)及同龄野生型小鼠分别随机分为对照组、异氟醚组和电针组,每组8只。电针组取"百会""涌泉"穴,连续电针3d;电针处理后异氟醚组和电针组吸入1.2%异氟醚4h。Morris水迷宫测试小鼠的学习记忆能力;免疫组化法检测海马CA 1区激活型Caspase-3的表达;Western blot法检测海马Bcl-2及Bax的表达。结果:AD小鼠5d平均逃避潜伏期明显高于野生型小鼠,第一象限停留时间百分比及60s内穿越平台次数明显低于野生型小鼠(P<0.05)。AD小鼠异氟醚组5d平均逃避潜伏期明显高于对照组,第一象限停留时间百分比及60s内穿越平台次数低于对照组(P<0.05);电针组5d平均逃避潜伏期低于异氟醚组,第一象限停留时间百分比及60s内穿越平台次数高于异氟醚组(P<0.05)。AD小鼠海马CA 1区激活型Caspase-3的表达明显高于野生型小鼠(P<0.05)。AD小鼠海马CA 1区Caspase-3阳性表达,异氟醚组高于对照组,电针组低于异氟醚组(均P<0.05)。与野生型小鼠相比,AD小鼠海马Bcl-2蛋白的相对表达量减少,Bax蛋白的相对表达量增多,Bcl-2/Bax比值下降(P<0.05)。AD小鼠海马Bcl-2/Bax比值,异氟醚组较对照组减小(P<0.05),电针组与异氟醚组相比明显提高(P<0.05)。结论:电针可通过抑制异氟醚导致的AD小鼠海马区激活型Caspase-3的过量表达,降低海马Bax蛋白的表达,提高Bcl-2/Bax比值,减轻异氟醚诱使的AD样病理神经毒性,对小鼠的学习记忆具有保护作用。

Objective To investigate the protection mechanism of electroacupuncture（EA）therapy against Alzheimer’s disease（AD）-like neurotoxicity induced by Isoflurane.Methods Twenty-four APPswe/PS 1dE 9double transgenic mice（one of the most extensively used transgenic mouse model of AD）and 24 littermate wild-type mice were randomly assigned into control（Con）group,isoflurane（Iso）group and EA group,respectively（n=8in each group）.EA（2Hz/100 Hz,1mA）was applied to＂Baihui＂（GV 20）and＂Yongquan＂（KI 1）for 15 min,once a day for 3days.The transgenic mice were exposed to a closed box filled with 1.2%Isoflurane＋30% O2＋70% N2 for 4h.The animals’ learning-memory ability was detected by Morris water maze test.The expression of cleaved Caspase-3in the CA 1area of hippocampus was detected by immunohistochemistry,and that of hippocampal Bcl-2and Bax proteins detected by Western blot.Results Compared with the wilde-type mice,the average escape latency of place navigation test was significantly longer,while the percentage of target-quadrant stay time and the targetplatform crossing times of spacial probe test were marked decreased in AD＋Iso mice（P〈0.05）.After acupuncture intervention,the abovementioned changes were reversed（P〈0.05）.Correspondingly,compared with the AD-Con group,the number of hippocampal activated Caspase-3-positive cells and the expression of Bax protein were significantly increased in the AD-Iso group（P〈0.05）.After EA intervention,the increased Caspase-3-positive cell number and Bax protein expression were remarkably down-regulated in the AD-EA group,and the decreased ratio of Bcl-2/Bax in AD-Iso mice was obviously up-regulated in AD-EA mice（P〈0.05）.No significant changes were found in the average escape latency,the percentage of target-quadrant stay time and the target-platform crossing times,and in the number of hippocampal activated Caspase-3-positive cells,the expression levels of hippocampal Bcl-2and Bax and the ratio of Bcl-2/Bax in the three groups of wilde-type mice（P〉0.05）.ConclusionEA intervention can improve the learning-memory ability in AD＋Isoflurane mice,suggesting a reduction of AD-like neurotoxicity,which may be associated with its actions in inhibiting the overexpression of activated Caspase-3and Bax proteins in the hippocampus.