Effect Of Electroacupuncture On Synaptic Function In Hippocampus Of SAMP8 Mice

Objective:To observe the learning and memory ability of SAMP8 mice,the synaptic ultrastructure of hippocampal neurons,the synaptic proteins in hippocampal neurons[synaptic vesicles(synaptophysin,SYN)and the postsynaptic compact region protein(Postsynaptic density 95,PSD95)]expression,from the angle of contact to reveal the role of electroacupuncture(EA)in the treatment of AD mechanism,and for EA in the clinical prevention and treatment of AD provides experimental and theoretical basis.Methods:Thirty-six 7-month-old SAMP8 mice were randomly divided into two groups:model group(n=18)and EA group(n=18);and SAMR1 mice were treated as control group(n=18).The EA group was treated with EA.The mouse used a homemade net pocket to fix,The EA groud selected Baihui acupoint(DU20),Dazhui acupoint(GV14)and bilateral Shenshu acupoint(BL23)for EA treatment,and after the needle is inserted,do not perform manual stimulation,connect the G6805-I EA device for treatment,GV14 connects to the positive electrode of the EA device,and one BL23 connects to the negative electrode of the EA device.It applies a continuous wave with a frequency of 2 Hz.The current intensity oscillates with the needle shank and the mouse can withstand quiet and not struggle.An individual EA session was administered daily for 20 min.8 days,and 2 days rest for a period of 30 days.The EA treatment was not performed in the model group and the control group,and only the same manner,the same time and the same degree of grasping and mouse fixation were performed.The Morris water maze test was used to test the learning and memory ability of mice.The morphology and density of synapse in hippocampal CA1 region was observed by transmission electron microscopy.The expression of SYN and PSD95 in hippocampal CA1 region of mice were detected by immunohistochemistry and Western blot.Results:1.Morris Water Maze:1)Comparison of escape latency between mice in each group:In the 5-day positioning navigation experiment,the escape latency of the model group was significantly increased compared with the control group(P<0.01).Compared with the model group,the average escape latency of the EA group was shorter(P<0.05);2)Each group of mice explored the time of the original platform stay and the number of crossing platforms:Compared with the control group,the time spent in the original platform quadrant of the model group was significantly shorter(P<0.01);and the number of crossings across the platform was significantly reduced(P<0.01).Compared with the model group,the stay time of the original platform in the EA group was prolonged(P<0.05),the number of crossing the platform increased(P<0.05).2.Transmission Electron Microscopy:Compared with the control group,the synaptic gap was increased or disappeared in the model group,the anterior and posterior membranes were not clear,the synaptic vesicles were reduced,and the postsynaptic densities became thinner;compared with the model group,the synapse structure was more complete in the EA group.The presynaptic and posterior membrane boundaries are clear,and synaptic vesicles are more.3.Immunohistochemical:Under light microscopy,the expression of SYN in neurons in hippocampal CA1 region was tan,which was mainly expressed in neuronal cell membrane and cytoplasm.Compared with the control group,the expression of SYN in the model group was the most intense,light yellow,and the average optical density of the positive target decreased significantly(P<0.01).Compared with the model group,the average optical density of the positive target of the EA group was significantly increased(P<0.01).The positive expression of PSD95 is brown and mainly expressed in the neuronal cell membrane.Compared with the control group,the positive expression of PSD95 in the model group was the weakest,light brown,and the average optical density of the positive target was significantly reduced(P<0.01);compared with the model group,the average optical density of the positive target of the EA group was significantly increased(P<0.01),4.Western blot:The overall trend of expression of SYN and PSD95 was the same,and compared with the control group,the average relative expression of SYN and PSD95 protein in the model group was significantly reduced(P<0.01);compared with the model group,the SYN group of the EA group The average relative expression of PSD95 protein was significantly increased(P<0.01).Conclusion:1.Synaptic ultrastructural changes in hippocampal CA1 neurons in mice with AD were mainly characterized by increased or disappeared synaptic cleft,unclear anterior and posterior membranes,reduced synaptic vesicles,and postsynaptic densities.Thinning synaptic function protein SYN and PSD95 expression decreased.2.EA treatment is conducive to maintaining the integrity of the synaptic structure,increased synaptic vesicles,and is beneficial to improve the synaptic structure of SAMP8 mice,thereby enhancing synaptic function.3.EA can increase the expression of synaptic function proteins SYN and PSD95 in hippocampal CA1 region and increase synaptic function.