基于BDNF/TrkB/PI3K/Akt信号通路的滋肾醒脑汤对阿尔茨海默病大鼠学习记忆能力的影响

目的基于BDNF/TrkB/PI3K/Akt信号通路观察滋肾醒脑汤对阿尔茨海默病(AD)大鼠学习记忆能力的影响,探讨其可能的作用机制。方法采用侧脑室注射β-淀粉样蛋白制备AD大鼠模型,假手术组注射等体积生理盐水,将成模大鼠随机分为模型组、中药组及阳性对照组,每组6只,中药组及阳性对照组分别予滋肾醒脑汤(16.74 g/kg)和盐酸多奈哌齐混悬液(0.45 mg/kg)灌胃,假手术组和模型组灌胃等体积蒸馏水,每日1次,连续4周。采用Morris水迷宫实验进行大鼠行为学检测,TUNEL染色检测海马组织神经细胞凋亡情况,Western blot检测海马组织脑源性神经营养因子(BDNF)、酪氨酸激酶受体B(TrkB)蛋白表达,免疫组化检测海马组织PI3K、Akt蛋白表达。结果与假手术组比较,模型组大鼠逃避潜伏期明显延长,跨越平台次数减少,目标象限停留时间缩短(P<0.05,P<0.01),海马组织神经细胞凋亡率明显升高,BDNF、TrkB、PI3K、Akt蛋白表达明显降低(P<0.05);与模型组比较,中药组及阳性对照组大鼠逃避潜伏期明显缩短,跨越平台次数增加,目标象限停留时间延长(P<0.01,P<0.05),海马组织神经细胞凋亡率明显降低,BDNF、TrkB、PI3K、Akt蛋白表达明显升高(P<0.05,P<0.01),中药组与阳性对照组差异无统计学意义(P>0.05)。结论滋肾醒脑汤可改善AD大鼠学习记忆能力,其机制可能与上调BDNF/TrkB/PI3K/Akt信号通路蛋白表达,减少神经细胞凋亡有关。

Effects of Zishen Xingnao Decoction on Learning and Memory Ability of Alzheimer Disease Rats Based on BDNF/TrkB/PI3K/Akt Signaling Pathway

Objective To explore the effects of Zishen Xingnao Decoction on the learning and memory ability of Alzheimer disease(AD)model rats based on the BDNF/TrkB/PI3K/Akt signaling pathway;To discuss its possible mechanism.Methods AD rat model was established by intracerebroventricular injection ofβ-amyloid protein,and the sham operation group was injected with equal volume of normal saline.The model rats were randomly divided into model group,traditional Chinese medicine(TCM)group and positive control group,with 6 rats in each group.TCM group and positive control group were given Zishen Xingnao decoction(16.74 g/kg)and donepezil suspension(0.45 mg/kg)by gavage respectively,sham operation group and model group were given the same volume of distilled water by gavage,once a day for 4 weeks.Morris water maze test was used to observe the behavior of rats;TUNEL staining was used to detect neuronal apoptosis in hippocampus;Western blot was used to detect the expression of BDNF and TrkB protein in hippocampus.Immunohistochemistry was used to detect the expression of PI3K and Akt protein in rat hippocampus.Results Compared with the sham operation group,the escape latency was significantly longer,the number of crossing platforms was reduced,the stay time in the target quadrant was shorter(P<0.05,P<0.01)in the model group,the apoptosis rate of neurons in hippocampal significantly increased,and the proteins expression of BDNF,TrkB,PI3K and Akt significantly decreased(P<0.05).Compared with the model group,rats in the TCM group and the positive control group had shorter escape latency,the number of crossings platform was increased,the stay time in the target quadrant was longer(P<0.05,P<0.01),the apoptosis rate of hippocampal neurons decreased,the proteins expression of BDNF,TrkB,PI3K and Akt were significantly increased(P<0.05,P<0.01).There was no significant difference between the TCM group and the positive control group(P>0.05).Conclusion Zishen Xingnao Decoction can improve the learning and memory ability of AD model rats,and the mechanism may related to up-regulate the proteins expression of BDNF/TrkB/PI3K/Akt signaling pathway,and reducing the apoptosis of neurons.