| Objective:Take the SAMP8 mice, AD animal model, as research object, to observe the effect of acupuncture on neuronal synaptic plasticity, level of glucose, lactate and pyruvate, and the expression of GLUT3, MCT2, MCT4 transporters in hippocampus, so as to investigate the mechanism of promoting synaptic plasticity from neurnal energy sbustrate transportation aspect, and to provide experimental evidences for treating AD by acupuncture.Methods:1. The learning and memory ablility of SAMP8 and SAMR1 mice was detected by using Morris water maze (MWM) test, SAMP8 mice with decreased learning and memory ability were screen out as animal models of AD, then randomly divided into model group and acupuncture group. The same-month-aged SAMR1 mice with normal learning and memory ability were selected as control group.2. The acupuncture treatment on DU20 (Baihui) and KI1 (Yongquan) was applied once daily for 20 minutes, and 5 days as a treatment course, last for 8 courses with 2 days interval between adjacent courses. Mice were sacrificed after treatment, their brains were isolated.3. Observe the post synaptic density (PSD), width of synaptic cleft and the curvature of synaptic interface of neurons in CA1 subregion of hippocampus by using electron microscope. The level of glucose, lactate and pyruvate were detected by using MD. With the combination of immunohistochemistry, western blot and image analysis, localization and quantitative investigation of GLUT3, MCT2 and MCT4 transporters expression were made in hippocampal subregions.Results:1. The Morris water maze test results indicated that, compared to control group, the learning and memory ability of mice in model group is decreased. In place navigation test (PNT), the escaping latency is significantly prolonged (P<0.01), the total distance of swimming is increased (P<0.05). In spatial probe trail (SPT), the percentage of time and distance of swimming in target quadrant is significantly decreased (P<0.01), the number of times crossing the target area and effective area is significantly decreased (P<0.01). Compared to model group, after 8 course of treatment, mice in acupuncture group showed an improvement in the escaping latency and the total distance of swimming in 4 th and 5th day (P<0.05), and in the percentage of time and distance of swimming in target quadrant (P<0.05), and in the number of times crossing effective area (P<0.05). There is no difference in the number of times crossing the target area between acupuncture group and model group (P<0.05).2. The synaptic plasticity results showed that, compare to control group, mice in model group showed decreased PSD (P<0.01), and increased width of synaptic cleft (P<0.01). Compared to model group, after 8 course of treatment, mice in acupuncture group showed increased PSD (P<0.05), and decreased width of synaptic cleft (P<0.05).3. Compare to control group, mice in model group showed a significantly decrease in level of glucose, lactate and pyruvate (P<0.01). Compare to model group, after 8 course of treatmen, mice in acupuncture showed a significantly decrease in level of glucose, lactate and pyruvate (P<0.01). In vivo microdialysis in SAMP8 mice using CMA7 probe, the recovery of lactate is 16.25%, and the recovery of glucose is 19.18%.4. Mice in model group showed, compared to control group, significant decrease in total expression of GLUT3 (P<0.01), MCT2 (P<0.01) and MCT4 (P<0.05) in hippocampus. The decrease in total expression of GLUT3 mainly appeared in CA1 and DG subregions. The decrease of MCT2 expression appeared in CA1 (P<0.01), CA3 (P<0.01) and DG (P<0.01) subregions at the same time. The decrease of MCT4 expression mainly appeared in CA1 (P<0.01) subregion. Compared to model group, after 8 course of treatment, mice in acupuncture group showed an increased in total expression of MCT2 (P<0.01), GLUT3 (P<0.01), and no significant difference in total expression of MCT4 (P>0.05). The increase of GLUT3 and expression mainly appeared in CA1 (P<0.01) and DG (P<0.01) subregions. The increase of MCT2 expression mainly appeared in CA1 (P<0.01), DG (P<0.01) subregions, and the expression of MCT4 in CA1 subregion is significantly increased (P<0.01).The ratios of MCT4 to MCT2 showed, compared to control group, no significance in CA1, CA3, DG subregions (P>0.05). Compared to model group, after 8 course of treatment, mice in acupuncture group showed a decreased ratio in CA1 subregion (P<0.05), and there’s no significant difference in CA3, DG subregions (P>0.05). Conclusions:1. Acupuncture had an effect of improving the hippocampal neurons" synaptic plasticity and the learning and memory ability of SAMP8 mice.2. The level of hippocampal lactate, glucose and pyruvate decreased by acupuncture in 10-month-old SAMP8 mice.3. Regulating the expression of GLUTs and MCTs might be the mechanism of acupuncture for improving neuronal energy supply, metabolism and synaptic plasticity, and promoting learning and memory... |
PDF Full Text Request