Effects Of Electro-acupuncture On Learning/Memory Abilities And AVP Antagonist Aβ In CA1 Area Of Hippocampus In Rats With Vascular Dementia

ObjectiveIn this experiment, through the comparative observation of the indexes changes among the treatment groups and model group, such as APP, AVP and A β，in hippocampus CA1 areas of vascular dementia（VD） rats after cerebral ischemia-reperfusion, in order to explore the roles of AVP and A Aβ in synaptic transmission efficiency of rat’s brain under the action of electro-acupuncture（EA） intervention. Furthermore, to discover the specific target of AVP antagonist Aβ with EA interference, the changes of different indexes, including AVP and Aβ, as well as the results of behavioral tests, are compared between Acupuncture Therapy group 1（AT1 group, injecting AVP V₁-receptor blocker+EA） and Acupuncture Therapy group 2（AT2 group, EA only）.Methods120 adult male SD rats with SPF level were randomly divided into normal group, sham operation group, model group, medicine group, Acupuncture Therapy group 1（AT1 group）, and Acupuncture Therapy group 2（AT2 group）. The Modified Pulsinelli’s four-vessel occlusion （4-VO） method was used to make models——step 1 blocking the bilateral vertebral arteries by electric coagulation, step 2 reversible clipping bilateral common carotid arteries. After making a rat model of VD with disabilities of spatial memory and learning, screen out qualified VD rats by Morris water maze. Moreover, AT1 group also need a rejection of V₁-receptor blocker in the hippocampal CA1 area. As for the treatments, medicine group use intragastric administered with Piracetan suspension, while both of the acupuncture therapy groups use the same electro-acupuncture treatments. Finally the changes of different indexes of VD rats in all groups are tested by the following methods:rat’s behavioral test with Morris water maze, the protein expression with Western Blot and the gene expression with fluorescence PCR for APP, AVP, Aβ 1-40, Aβ 1-42, and the enzyme content with ELISA for α/β/γ secretase.Results1. Morris water maze test resultsCompared with other groups, the average escape latency of model group was much longer than that of others, with a statistically significant difference （P<0.01）. Compared with the model group, the escape latency of treatment groups （medicine group, AT1 group and AT2 group） were statistically shorter （P＜0.01）. Mutually compared among three treatment groups, a significant shorter escape latency of AT2 group was seen than that of medicine group （P＜0.05）, but there was no statistical difference between AT groups and medicine group, AT1 group and AT2 group.As for the frequency of passing through the originate platform within 120 seconds, the model group got the least frequency in all groups with a statistically significant difference （P<0.01）. And the frequencies of treatment groups were statistically remarkably increased comparing with the model group （P<0.01）. But there was no statistical difference among three treatment groups.2. Western Blot test resultsAβ 1-40:The protein expression of Aβ 1-40 in the three treatment groups were significantly decreased compared with the model group （P＜0.01）. With the comparison among three treatment groups, the Aβ 1-40 protein expression of AT2 group decreased more significantly than those in the other two groups （P＜0.05）, but there was statistical difference between medicine group and AT1 group.Aβ1-42:AT groups had obvious lower level of protein expression of A β1-42 than control group with a statistical difference （both P＜0.01）. The medicine group showed no statistical difference comparing with model group （P＜0.05）. Among the three treatment groups, AT groups had lower level of protein expression of Aβ 1-42 than the control group, with a statistical difference （both P<0.05）, but no difference was shown between the two AT groups.AVP:Three treatment groups compared with the control group, AVP protein expression increased significantly, which with significant differences （P＜0.01）. Among three treatment groups, AT2 group got the highest level of AVP protein expression, while AT1 group got the lowest one, with a statistically significant difference compared with the other two （both P＜0.01）.APP:Compared with model group, three treatment groups had lower level of APP protein expression with a significant difference （P＜0.01）. Among three treatment groups, the APP protein expression in AT groups decreased more obviously than medicine group, with a statistically significant （P<0.05）, but there was no statistical difference between the two AT groups.3. Fluorescence PCR test resultsAβ 1-40:Compared with the model group, the gene expression of Aβ1-40 were remarkably decreased in three treatment groups with a significant differences （P<0.01）. Compared among three treatment groups, the level of gene expression of Aβ1-40 in AT2 group was much lower than that of other two groups with statistical difference （P<0.05） and a even more significant difference compared with medicine group （P<0.01）. But there was no statistical difference between medicine group and AT1 group.Aβ1-42:Compared with the model group, the gene expression of A 31-42 were obviously decreased in three treatment groups with a significant differences （P＜0.01）. Among three treatment groups, AT groups were found a much lower level of gene expression of Aβ1-42 comparing with medicine group with a significant difference （P＜0.01）. But there was no statistical difference between AT groups.AVP:Three treatment groups compared with the control group, AVP gene expression increased significantly, which with significant differences （P＜0.01）. Among three treatment groups, AT2 group got the highest level of AVP gene expression, while AT1 group got the lowest one, all with a statistically significant difference compared with the other two （both P<0.01）.APP:Compared with model group, three treatment groups had lower level of APP gene expression with a significant difference （P<0.01）. Among three treatment groups, as for the APP gene expression, AT2 group got the highest level, followed by AT1 group and with the least on in medicine group, with a statistically significant differences in the all comparisons （P<0.05）.4. ELISA test resultsα-secretase:Compared with the model group, the three treatment groups showed an obvious increase in the content of α-secretase with a significant difference （P＜0.01）. Among three treatment groups, AT groups got higher level of the content of α-secretase compared with medicine group, with a statistical difference （P<0.05）. Moreover, AT2 group got even more significant statistical difference comparing with the other two groups （P<0.01）.β-secretase:Compared with the model group, the three treatment groups showed an obvious decrease in the content of β-secretase with a significant difference （P＜0.01）. Among three treatment groups, AT groups got lower level of the content of β-secretase compared with medicine group, with a statistical difference （P＜0.05）. But there was no statistical difference between AT groups.γ-secretase:Compared with the model group, the three treatment groups showed an obvious decrease in the content of y-secretase with a significant difference （P<0.01）. There was no statistical difference among three treatment groups.Conclusion1. After acupuncturing "Baihui" and "Dazhui", the ability of learning and memory in Vascular dementia can be improved with showing a shorter escape latency. This effect may be resulted from the lower level expressions of gene and protein of APP、Pβ1-40、Aβ1-42 and the content of β/γ-secretase in CA1 area of hippocampus, as well as the higher level expression of gene and protein of AVP and content of α-secretase causing by electro-acupuncturing on vascular dementia rats.2. Autocrine AVP can effectively block or attenuate the toxic effects of Aβon hippocampal neurons in form of Aβ antagonists. This includes:（1） AVP may inhibit the damage to neurons as the blocker of Aβ1-40、Aβ1-42 and play a positive role in the degradation and removal of Aβ. （2） Though showing no suppressive influence in the generation of Aβ monomer, AVP can be helpful in reducing the formation of A β from APP, so as to improve the pathological condition of vascular dementia.