Effects of electroacupuncture at "Baihui" and "Yongquan" on the levels of synaptic plasticity related proteins postsynaptic density-95 and synaptophysin in hippocampus of APP/PS1 mice / 针刺研究

ABSTRACT

OBJECTIVE: From the perspective of β-amyloid (Aβ) toxicity and synaptic plasticity, the mechanism of electroacupuncture to improve learning and memory ability in the early pathological stages of Alzheimer's disease was explored. METHODS: Twelve male amyloid-protein precursor (APP)/γ-secretase (PS1) double transgenic AD mice were randomly and equally divided into electroacupuncture (EA) group and model group, and other 6 male C57BL/6 mice were used as the normal group. EA (1 Hz/50 Hz, 0.5 mA) was applied to "Baihui" (GV20) and bilateral "Yongquan"(KI1) for 15 min, once every other day for 6 weeks. Immunofluorescence was used to observe the positive expression of Aβ in the left hippocampus. Immunohistochemistry was used to observe the positive expression of postsynaptic density-95 (PSD-95) in the left hippocampus. Western blot was used to detect the expression of PSD-95 and synaptophysin (SYN)in the right hippocampus. RESULTS: Immunofluorescence results showed that extracellular Aβ was seen in the model group and electroacupuncture group, but no senile plaques were seen. Compared with the normal group, the expression level of Aβ in the hippocampus of the model group increased significantly (P<0.01). Compared with the model group, the expression of Aβ in the hippocampus of the EA group decreased (P<0.05). Immunohistochemical results showed that compared with the normal group, the PSD-95 positive expression in the model group was decreased(P<0.05). Compared with the model group, the expression of PSD-95 in the EA group was increased (P<0.05). Western blot results showed that compared with the normal group, the expression levels of PSD-95 and SYN in the hippocampus of the model group were decreased (P<0.05, P<0.01). Compared with the model group, the expression levels of PSD-95 and SYN in the EA group were increased (P<0.05，P <0.01). CONCLUSION: EA can reduce the expression of Aβ in the hippocampus of APP/PS1 mice and increase the expression of PSD-95 and SYN, which may contribute to its effect in improving the synaptic plasticity.