苓桂术甘汤调节PKA/CREB通路改善阿尔茨海默病小鼠海马神经元突触损伤的作用研究

Study on the Effect of Linggui Zhugan Decoction on Regulating PKA/CREB Pathway and Improving Hippocampal Neuronal Synaptic Damage in Alzheimer's Disease Mice

目的观察苓桂术甘汤对阿尔茨海默病(Alzheimer's disease,AD)小鼠海马神经元突触损伤的改善作用,并探讨其作用机制。方法采用双侧海马注射Aβ1-42法建立AD小鼠模型,造模成功后随机分为AD组,苓桂术甘汤低、中、高剂量组(4.29、21.45、42.90 g/kg)及石杉碱甲组(0.04 mg/kg),每组各10只。灌胃给药4周后,Morris水迷宫检测各组大鼠学习记忆能力;透射电镜观察海马区突触超微结构变化并测量突触后致密带厚度;HE染色观察海马组织病理变化;Western blot检测海马组织蛋白激酶A(protein kinase A,PKA)、cAMP反应元件结合蛋白(cAMP response element binding protein,CREB)、磷酸化-CREB(phosphorylation-CREB,p-CREB)蛋白表达。结果与AD组比较,高、中、低剂量组大鼠逃避潜伏期明显缩短,穿越原隐藏平台次数明显增加,目标象限停留时间明显延长,海马神经元突触后致密带厚度明显增大,海马组织PKA蛋白表达量、p-CREB/CREB明显升高(P<0.05)。结论苓桂术甘汤可能通过激活PKA/CREB信号通路减轻海马神经元突触损伤,进而改善AD小鼠的学习记忆能力。

Objective To observe the effect of Linggui Zhugan decoction on the synaptic damage of hippocampal neurons in Alzheimer's disease(AD)mice,and to explore the possible mechanism.Methods The model of AD were established by bilateral hippocampal injection of Aβ1-42,and they were randomly divided into Linggui Zhugan decoction low,medium,high dose groups(4.29,21.45,42.90 g/kg)and Huperzine A group(0.04 mg/kg).After administration for 4 weeks,the learning and memory ability of mice was detected by Morris water maze test.The transmission electron microscope was used to observe the synaptic ultrastructure,and the post-synaptic density was measured.The hippocampus pathological changes were compared.The expression of protein kinase A(PKA),cAMP response element binding protein(CREB),and phosphorylation-CREB(p-CREB)protein in hippocampus were detected by Western blot method.Results Compared with AD group,in high,medium and low dose groups,the escape latency of rats were significantly shortened,the times of crossing the original hiding platform were significantly increased,the residence time in the target quadrant were significantly extended,and the thickness of postsynaptic dense matter in hippocampal neurons were significantly increased,the expression of PKA protein and p-CREB/CREB in hippocampus were significantly increased(P<0.05).Conclusion Linggui Zhugan decoction may reduce the synaptic damage of hippocampal neurons by activating PKA/CREB signaling pathway,and then improve the learning and memory ability of AD mice.