Effects Of Early Electroacupuncture On Synaptophysin And PSD-95 Expression In Different Brain Regions Of SAMP8 Mice

Objective:To observe the effects of early electroacupuncture(EA)on synaptophysin(SYN)and postsynaptic density 95(PSD-95)expression in different brain regions of SAMP8 mice,and to investigate the intervention time of EA in the treatment of Alzheimer’s disease(AD).Methods:Forty-eight SAMP8 mice were randomly divided into model group,3-month-old EA group,6-month-old EA group and 9-month-old EA group(representing the early,middle and late EA groups,respectively),with 12 mice in per group,and 12 in normal aging SAMR1 mice of the same age as the control group.The mice were fixed with a self-made net fixation plate.The EA group were intervened with acupuncture at “Baihui”(DU 20),“Dazhui”(GV 14)and bilateral “Shenshu”(BL 23),connect the G6805-I EA device with “dazhui” and “shenshu”(Bilateral alternation)for 20 minutes per time,2 Hz,1.5-2 mA,once a day,8 days as a course of treatment,with an interval of 2 days,3 period of treatment totally.The model group and the control group did not receive EA treatment,only the same way,the same time and the same degree of grasping and fixation as the EA group.Morris water maze experiment was used to detect the learning and memory ability of mice in each group at the age of 10 months.After the experiment,immunohistochemistry and western blot were used to detect the expression of SYN and PSD-95 in the cortex and hippocampus.Results:1.Morris Water Maze: Compared with the control group,the escape incubation period of mice in the model group was significantly prolonged(P<0.01),the residence time in the original platform quadrant was significantly shortened,and the number of crossing the platform was significantly reduced(P<0.01).Compared with the model group,the evading latency was shorter in each EA group(P<0.05),the residence time in the original platform quadrant of the 3-month-old and 6-month-old EA group was longer,and the number of crossing platforms was increased(P<0.05),but there was no statistical significance in the 9-month-old EA group.Compared with the 6-month-old EA group,the 3-month-old EA group had a shorter escape latency period(P<0.05),significantly longer stay time in the original platform quadrant,and significantly more times of crossing the platform(P<0.01).Compared with the 9-month-old EA group,the 3-month-old EA group had significantly shorter escape latency period(P<0.01),significantly longer stay time in the original platform quadrant,and significantly more times of crossing the platform(P<0.01).2.Immunohistochemical: Compared with the control group,the positive expressions of SYN and PSD-95 in the cortex and hippocampus of the model group were significantly decreased(P <0.01).Compared with the model group,the positive expressions of SYN and PSD-95 in the cortex and hippocampus of the EA group were increased(P<0.05).Compared with the 6-month-old EA group,the MOD values of SYN and PSD-95 proteins in the cortex and hippocampus of the 3-month-old EA group were higher(P<0.05).Compared with the 9-month-old EA group,the MOD values of SYN and PSD-95 proteins in the cortex and hippocampus of the 3-month-old EA group were higher(P<0.05).3.Western blot: Compared with the control group,the relative expression levels of SYN and PSD-95 in the cortex and hippocampus of the model group were significantly reduced(P<0.01).Compared with the model group,the expression levels of SYN and PSD-95 proteins in the cortex and hippocampus of mice in the EA group at 3-month-old and 6-month-old were all increased(P<0.05),and the statistical difference was not significant in the EA group at 9-month-old.Compared with the 6-month-old EA group,the 3-month-old EA group had higher expression levels of SYN and PSD-95 proteins in cortex and hippocampus(P<0.05).Compared with the 9-month-old EA group,the 3-month-old EA group had higher expression levels of SYN and PSD-95 proteins in cortex and hippocampus(P<0.05).Conclusion:1.EA of “Baihui”,“Dazhui” and “Shenshu” could improve the learning and memory ability of SAMP8 mice.2.EA can improve the expression of synaptic functional protein SYN and PSD-95 in cortex and hippocampus,and improve synaptic function.3.The degree of improvement in electrical treatment of AD is related to the time of treatment,and the early efficacy is better than the middle and late efficacy.