电针对Aβ25-35致阿尔茨海默病模型大鼠cAMP/PKA/CREB信号转导通路的影响

Influence of electroacupuncture on cAMP/PKA/CREB signal transduction pathways in Aβ25-35 induced Alzheimer's disease model rats

目的探讨电针对Aβ25-35导致的阿尔茨海默病模型大鼠应用电针刺激后cAMP/PKA/CREB信号转导通路的变化。方法 48只健康雌性SD大鼠随机分为AD模型组、电针组、假手术组和正常对照组各12只。模型组与电针组采用Aβ25-35建立AD模型后电针组给予电针刺激,模型组未给予电针刺激;假手术组双侧海马注射等量生理盐水;正常对照组不做任何处理。4组均采用Morris水迷宫实验检测大鼠记忆与空间探索能力,采用分光光度计法检测脑组织超氧化物歧化酶与丙二醛水平,采用放射免疫法检测海马cAMP水平,采用免疫组织化学法检测海马5-羟色胺1A受体、蛋白激酶A与p-CREB蛋白表达水平,采用Western blot检测海马总Tau蛋白表达水平及Tau蛋白Ser396位点磷酸化情况。结果与模型组比较,电针组、假手术组与对照组逃避潜伏期缩短、跨越平台次数增多、目标象限停留时间延长(P<0.05),脑组织中超氧化物歧化酶、5-羟色胺1A受体、蛋白激酶A及p-CREB水平增高(P<0.05),丙二醛、总Tau蛋白、pTau-Ser396、c-fos蛋白水平降低(P<0.05);电针组总Tau蛋白、c-fos及PKA水平高于假手术组(P<0.05),与对照组比较差异无统计学意义(P>0.05)。结论电针可明显提高阿尔茨海默病大鼠学习记忆功能和空间探索能力,可能是通过拮抗cAMP/PKA/CREB信号转导通路相关蛋白的异常改变起作用。

Objective To explore the influence of electroacupuncture on cAMP/PKA/CREB signal transduction pathways in Aβ25-35 induced Alzheimer＇s disease （AD） model rats. Methods Forty-eight healthy female SD rats were randomly divided into model group, electroacupuncture group, sham operation group and normal control group, with 12 rats in each group. After AD models were established by injecting Aβ25-35, electroacupuncture group received electroacupuncture stimulation, and model group did not receive electroacupuncture stimulation. Sham operation group was injected the same volume of normal saline into bilateral hippocampus. And normal control group received no treatment. Morris water maze was adopted to observe learning and memory ability and spatial seeking ability in all groups. Superoxide dismutase and malondialdehyde levels were detected by spectrophotometer. The level of hippocampal cAMP was detected by radioimmunaossay. The expressions of hippocampal 5-HT AR, PKA and p-CREB proteins were detected by immunohistochemical method. Total content of Tau protein in brain neurons and Tau protein Ser396 phosphorylation sites were tested by Western blot technique. Results Compared with model group, escape latency shortened, frequencies of leaping increased and time spent in the target quadrant extended （P%0.05）, the contents of superoxide dismutase, 5-HT1AR, PKA and p-CREB increased （P%0.05）, and levels of malondialdehyde, total Tau protein, pTau-Ser396 and c-los protein decreased （P〈 0.05） in electroacupuncture group, sham operation group and normal control group. The levels of Tau protein, c-fos and PKA were higher in electroacupuncture group than those in sham operation group （P〈 0.05）, which showed no significant difference with normal control group （P〈 0.05）. Conclusions Electroacupuncture can significantly improve the learning and memory ability and spatial seeking ability of AD rats by antagonism of abnormal expression of cAMP/PKA/CREB signal transduction pathway related proteins.