| Objective:After the cerebral ischemia-reperfusion in the vascular dementia(VD) rats, this research observed the changes of A β1-40, Aβ 1-42 protein and gene expression level in the hippocampus CA1 area, the results of Morris water maze experiment, and the morphology of synapses in the influence of learning and memory. To explore the differences of Aβ in the rat’s hippocampal CA1 area and the abilities of learning and memory, the comparative experiments were done among the electric-acupuncture groups (including the high frequency group with 100 Hz, the variable frequency group with 2/100 Hz, and the low frequency group with 2Hz), blank group, control group, model group and the western medicine group. What’s more, by the methods of molecular biology, behavioral science and morphology, the comparative observations between these three groups——high frequency group with 100 Hz, variable frequency group with 2/100 Hz, and the low frequency group with 2Hz in electric-acupuncture groups also had been done to find out the changes in gene and protein expression of Aβ in the rat’s hippocampal CA1 area and the abilities of learning and memory causing by different electric frequency.Methods:140 SD rats were randomly divided into 7 groups——blank group, control group, model group, western medicine group, high frequency (100 Hz), variable frequency (2/100 Hz) and low frequency group (2 Hz). In addition to randomly selecting 10 as the blank group and 12 as the control group, the international recognized four-vessel occlusion (4-VO) method was used to make models with all the rest of 128 rats. After selection,60 qualified vascular dementia rats were randomly divided into model group, western medicine group, low frequency group, variable frequency group and high frequency group and each one has 12 rats in groups.All the changes of different indexes of VD rats in all groups were tested by the following methods:morphological changes of synapses by observation with transmission electron microscopy (TEM), rat’s behavioral test with Morris water maze, the protein expression with Western Blot and the gene expression with fluorescence PCR for Aβ1-40 and Aβ1-42.In the end, all the data were tested by the statistical approach of LSD test in one-way analysis of variance, so as to explore the mechanism of different frequency electric acupuncture intervention of VD rat hippocampal CA1 area Aβ, and the influence in learning and memory.Results:1. Morris water maze results:Compared with other groups, the escape latency period of model group significantly prolonged and the crossing time of original table in the 120s increased (P＜0.05). Comparing the control group and the blank group, the changes in the escape latency period and the crossing time of original table in the 120s had no significant (P>0.05). Comparing the electric acupuncture treatment groups (including low frequency group, high frequency group and variable frequency group) with western medicine group, the escape latency period decreased and the crossing time of original table in the 120s increased (P＜0.05). Comparing low frequency, variable frequency group and high frequency group, the escape latency period reduced and the crossing time of original table in the 120s increased (P＜0.05). But comparing low frequency group and variable frequency group, the changes in the escape latency period and the crossing time of original table in the 120s had no significance (P＞0.05).2. Transmission electron microscopy (TEM) results:The control group obviously showed more synapses. And the structure of the presynaptic membrane, synaptic cleft and postsynaptic membrane was clearly visible.The presynaptic terminal could be seen a lot of round vesicles, and the postsynaptic membrane could be seen some density material of higher electron density. Compared with the control group, the synapses in the model group were obviously reduced. Part of the structure of the presynaptic membrane, synaptic cleft and postsynaptic membrane was indistinct. The round vesicles in the presynaptic terminal and density material in the postsynaptic membrane of the model group were less than the control group. Part of the synapses of the cupping treatment groups of the high frequency group, the low frequency group and the variable frequency group were still fuzzy，but comparison with the model group, the electric acupuncture treatment groups were improved in increasing the synapses and increasing the number of synaptic vesicles significantly presynaptic terminal. What’s more, the effect of the low frequency group and the variable frequency was more distinct.3. Western Blot method, fluorescence quantitative PCR detection results:The model group compared with other 6 groups, Aβ1-40 protein and gene expression increased (P＜0.05). Compared to the control group and the blank group, the changes of AP 1-40 protein and gene expression were of no significant (P＞0.05). The cupping treatment groups (the low frequency, the high frequency, the variable frequency group), compared with the western medicine group, Aβ1-40 protein and gene expression were decreased (P＜0.05). Compared with the high frequency group, Aβ1-40 protein and gene expression of the low frequency and the variable frequency group were decreased (P<0.05). Compared with the low frequency group, Aβ1-40 protein and gene expression of the variable frequency group were decreased (P＜0.05).The model group compared with other 6 groups, Aβ1-42 protein and gene expression increased (P＜0.05). Compared to the control group and the blank group, the changes of Aβ1-42 protein and gene expression were of no significant (P>0.05). The cupping treatment groups (the low frequency, the high frequency, the variable frequency group), compared with the western medicine group, Aβ1-42 protein and gene expression were decreased (P＜0.05). Compared with the high frequency group, Aβ1-42 protein and gene expression of the low frequency and the variable frequency group were decreased (P＜0.05). Compared with the low frequency group, Aβ1-42 protein and gene expression of the variable frequency group were decreased (P<0.05).Conclusions:Excluding the effect causing by simple surgical trauma, this experiment successfully made the VD model rats, which simulated the dementia animals process of cerebral ischemia-reperfusion injury with the 4-VO method. Considering the results of behavioral tests, morphological changes and molecular biology, electric acupuncture can be proved to effectively reduce the expression of gene and protein of Aβ1-40, Aβ1-42 in rat’s hippocampal CA1 area, thereby decreased the generation of senile plaques to improve the ability of learning and memory,as well as promoted the formation of new synapses and the modification of synaptic structure. In this way, the synapse plasticity can be improved to slow down the process of the pathological changes of vascular dementia. In addition, it had been found out that the results of low frequency and variable frequency electric acupuncture therapy were better than high frequency. |
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