| Objective:Explore whether electroacupuncture "GV20" and "GV24" points based on "Tongdu Tiao shen" theory can improve the learning and memory function of VD model rats by regulating the synaptic transmission efficiency and plasticity and the expression and phosphorylation level of related proteins of Vascular dementia(VD)model rats.Methods:Sixty male SD rats(280-300g)were taken and 12 were randomly selected into the sham-operated group to expose only the bilateral common carotid arteries.The other 48 SD rats were subjected to bilateral common carotid artery occlusion(2-Vessels Occlusion,2-VO)surgical preparation as the VD model,the 3D-TOF angiography of small animal MRI and the behavior detection of new object recognition were used to test the model;36 VD model rats successfully modeled were randomly divided into 3 groups using the random number table method: model group,electroacupuncture group and nonacupoint group,every group had 12 rats;The new object recognition index compares whether its behavioral baseline is consistent;electroacupuncture group taken electroacupuncture "GV20" and "GV24" points for intervention,sparse and dense wave 2/20 Hz,30min/time,1 time/Day,5 days/week,a total of 4 weeks;the nonacupuncture group used electroacupuncture non-menstrual and nonacu puncture under bilateral flank,the parameter and time were the same as the electroacupuncture group,the model group and the sham operation group were grasped and fixed under the same condi tions,having no electroacupuncture intervention;Morris water maze was used to detect the learning and memory function of rats in each group with space as reference;Isolate and prepare hippocampal living brain slices,and use patch clamp electrophysiological recording technology to detect the field potential charac teristics of hippocampal CA3-CA1 area of each group of rats,including Input-output(I/O curve),Paired-pulse facilitation ratios(PPR)and field excitatory postsynaptic potential(fEPSP)induced by 100 Hz high frequency stimulation(HFS).Westen blotting detected hippocampal synaptic plasticity-related proteins,including NMDA receptors(NMDAR2B),AMPA(GluR1)receptors,and CaMK? protein and their phosphorylation expression in each group.Results:(1)The test of VD model rats: After the VD model was established,the small animal mag netic resonance 3D-TOF angiography test showed that the bilateral common carotid arteries of rats were disappeared,and the surrounding new generation of small capillaries compensating,indicating that the 2-VO operation was successful;After the model was built,the behavioral experiment of new object recognition was performed.The results showed that compared with the sham operation group,the object preference coefficient of the model group was significantly redu ced at 1 hour(P<0.01),and the object preference coefficient at 24 h was also reduced(P<0.01)in model group.There was no statistical difference between the electroacupuncture group and the nonacupoint group(P>0.05),suggesting that the baseline of learning and memory behavior of the three groups before intervention was consistent;(2)The effect of electroacupuncture "GV20" and "GV24" points on the learning and memory function of VD model rats: After electroacupuncture intervention,the Morris water maze experiment results showed that in the 4-day positioning navigation experiment,compared with the operation group,the escape latency of rats in the model group,electroacupuncture group and nonacupuncture group increased on days 2,3 and 4(P<0.05);Compared with the model group and the nonacupoint group,the electroacupuncture group had a shorter escape latency on the 3rd and 4th days.In the memory test space exploration experiment,compared with the sham operation group,the number of crossing platform in the model group,electroacupuncture group and non-acupoint group was significantly reduced(P<0.01);however,compared with the model group,the number of crossing platforms in the electroacupuncture group increased significantly(P<0.05);suggesting that electroacupuncture "GV20" and "GV24" can improve the learning and memory extraction ability of VD model rats.(3)The effect of electroacupuncture "GV20" and "GV24" on the I/O curve and PPR of hippocampal CA3-CA1 area in VD model rats: Compared with the sham operation group,the I/O curve of model group at 10?A,20?A,30?A,40?A,50?A,60?A,70?A,80?A,90?A mean voltage stimulation was significantly reduced(P<0.01);while the I/O curve of electro acupuncture group significantly increased starting from the mean voltage of 20?A stimulation current compared with the model group(P<0.01);Compared of PPR ratios between six groups(10ms,20 ms,50ms,100 ms,200ms,and 500ms)of basic field potential stimulation in hippocampal CA3-CA1 area,there was no statistical difference between the sham operation group,model group,electroacupuncture group and non-acupoint group(P>0.05);it is suggested that electroacupuncture "GV20" and "GV24" can improve the basic transmission efficiency of hippocampal CA3-CA1 area in VD model rats,but had no effect on the release of presynaptic neurotransmitters.(4)The effect of electroacupuncture "GV20" and "GV24" on the LTP of the hippocampal CA3-CA1 area of the VD model rats: induced by HFS at 100 Hz,the fEPSP amplitude of the hippocampus CA3-CA1 area of the shamoperated increased by more than 70% compared with the baseline,indicating that the induction of long-term potentiation(LTP)in hippo campal CA3-CA1 area was successful;compared with the shamoperation group,the fEPSP in the CA3-CA1 area of the model group was significantly reduced(P<0.01),the difference was statistically significant;while the electroacupuncture group had higher fEPSPs in the CA3-CA1 area of the hippocampus than the model group(P<0.05);while,the electroa cupuncture group had not significantly different from the nonacupoint group(P>0.05),which was not statistically significant;It is suggested that electroacupuncture "GV02" and "GV24" can enhance LTP in hippocampal CA3-CA1 area of VD model rats and promote synaptic plasticity of them.(5)The effect of electroacupuncture "GV20" and "GV24" on the expression and phosphorylation level of NMDAR2 B,GluR1 and CaMK? protein in hippocampus of VD model rats.The results show that: Compared with the sham-operated group,the NMDAR2 B,AMPAR and CaMK? proteins and their phosphorylated expressions of the hippocampus of the model group were significantly reduced(P<0.05),the difference was statistically significant;while the electroacupuncture group was significantly more phosphorylated than the model group Elevated(P<0.05),the total protein concentration also increased;the non-acupoint group compared with the model group,the difference was not obvious(P>0.05),no statistical significance;suggest that electroacupuncture "GV20" and "GV24" can By regulating the expression and phosphorylation levels of NMDAR2 B,GluR1 and CaMK? proteins,the hippocampal synaptic plasticity of VD rats is improved.Conclusion:Electroacupuncture "GV20" and "GV24" can improve the basic synaptic transmission efficiency and synaptic plasticity in the hippocampal CA3-CA1 area of the VD model rats to improve their learning and memory ability.The molecular mechanism may be through the adjustment of post-synaptic membrane receptors and The expression of its calcium signaling related protein and its phosphorylation level. |
PDF Full Text Request