电针“智三针”对5xFAD小鼠Notch信号通路及突触可塑性的影响

Effects of electroacupuncture with “Zhi San Zhen” on Notch signaling pathway and synaptic plasticity in 5xFAD mice

背景:阿尔茨海默病是以认知功能障碍为主要临床表现的退行性神经系统疾病,针刺是治疗阿尔茨海默病的传统特色疗法,但作用机制尚不明晰。目的:观察电针“智三针”对5xFAD小鼠Notch信号通路、β-淀粉样蛋白及突触可塑性的影响。方法:将16只SPF级、雄性、6月龄5xFAD小鼠随机分为电针“智三针”组和模型组,每组8只,另取8只同条件C57BL/6小鼠作为野生对照组。电针“智三针”组进行电针“智三针”干预,每周5次,连续4周;模型组、野生对照组不进行干预。干预结束后,采用Morris水迷宫初步评价学习记忆能力;硫磺素S染色检测β-淀粉样蛋白斑块沉积情况;Western blot和qPCR检测跨膜受体蛋白Notch 1、Notch 1胞内段(Notch 1 intracellular domain,NICD)、Split多毛增强子1(hairy and enhancer of split 1,Hes 1)、Split多毛增强子5(hairy and enhancer of split 5,Hes 5)、突触生长蛋白(synaptophysin,SYN)、突触后密度蛋白95(postsynaptic density protein-95,PSD-95)及β-淀粉样蛋白的表达水平。结果与结论:①与模型组相比,野生对照组、电针“智三针”组小鼠逃避潜伏期缩短,穿越平台次数及目标象限停留时间增加(P<0.05);②与野生对照组相比,模型组小鼠海马区β-淀粉样蛋白斑块沉积显著增加,而电针“智三针”抑制了β-淀粉样蛋白斑块沉积(P<0.05);③与野生对照组相比,模型组小鼠海马组织中SYN、PSD-95、Notch 1、NICD、Hes 1及Hes 5 mRNA表达降低,β-淀粉样蛋白mRNA表达增加(P<0.05);与模型组相比,电针“智三针”组SYN、PSD-95、Notch 1、NICD、Hes 1及Hes 5 mRNA表达升高,β-淀粉样蛋白mRNA表达降低(P<0.05);④与野生对照组相比,模型组小鼠海马组织中SYN、PSD-95、Notch 1、NICD、Hes 1及Hes 5蛋白表达降低,β-淀粉样蛋白表达增加(P<0.05),与模型组相比,电针“智三针”组SYN、PSD-95、Notch 1、NICD、Hes 1及Hes 5蛋白表达增加,β-淀粉样蛋白表达降低(P<0.05);⑤结果表明,电针“智三针”能够改善5xFAD小鼠的学习记忆功能,其机制可能与抑制海马区β-淀粉样蛋白沉积及激活Notch信号通路从而增强神经突触可塑性有关。

BACKGROUND:Alzheimer’s disease is a degenerative neurological disorder characterized primarily by cognitive impairment.Acupuncture is a kind of traditional Chinese medicine therapy for treating Alzheimer’s disease,but its mechanism is not yet clear.OBJECTIVE:To observe the effects of electroacupuncture with“Zhi San Zhen”on the Notch signaling pathway,β-amyloid protein(Aβ)and synaptic plasticity in 5xFAD mice.METHODS:Sixteen male,6-month-old 5xFAD mice,SPF-grade,were randomly divided into the electroacupuncture with“Zhi San Zhen”group(electroacupuncture group)and the model group,with eight mice in each group.Eight SPF-grade,male,6-month-old C57BL/6 mice were used as the wild control(wild)group.The electroacupuncture group received electroacupuncture with“Zhi San Zhen”intervention,5 times a week for 4 consecutive weeks.The model group and the wild group did not receive electroacupuncture intervention.The Morris water maze was used to preliminarily assess their learning and memory abilities.Thioflavin S staining was performed to detect Aβplaque deposition.Western blot and real-time quantitative polymerase chain reaction(RT-qPCR)were used to measure the expression levels of transmembrane receptor protein Notch-1,Notch 1 intracellular domain(NICD),hairy and enhancer of split 1(Hes 1),hairy and enhancer of split 5(Hes 5),synaptophysin(SYN),postsynaptic density protein-95(PSD-95),and Aβ.RESULTS AND CONCLUSION:Compared with the model group,the wild group and the electroacupuncture group showed shortened escape latency,increased platform crossing times,and longer target quadrant dwell time(P<0.05).Compared with the wild group,the model group had significantly increased deposition of Aβplaques,while electroacupuncture with“Zhi San Zhen”inhibited the deposition of Aβplaques in the hippocampus of 5xFAD mice(P<0.05).Compared with the wild group,the model group had decreased mRNA levels of SYN,PSD-95,Notch 1,NICD,Hes 1,and Hes 5 in the hippocampal tissue of mice,and increased mRNA levels of Aβ(P<0.05).Electroacupuncture with“Zhi San Zhen”increased the mRNA levels of SYN,PSD-95,Notch 1,NICD,Hes 1,and Hes 5 in the hippocampal tissue,and decreased the mRNA level of Aβ(P<0.05).Compared with the Wild group,the model group had decreased protein expression levels of SYN,PSD-95,Notch 1,NICD,Hes 1,and Hes 5 in the hippocampal tissue of mice,and increased protein expression levels of Aβ(P<0.05).Electroacupuncture with“Zhi San Zhen”upregulated the protein expression levels of SYN,PSD-95,Notch 1,NICD,Hes 1,and Hes 5,and inhibited the protein expression of Aβ(P<0.05).To conclude,electroacupuncture with“Zhi San Zhen”can improve the learning and memory abilities of 5xFAD mice,possibly by inhibiting the deposition of Aβprotein and activating the Notch signaling pathway in the hippocampus to enhance synaptic plasticity.