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Objective:To explore the changes of dendritic spine morphology and structure in dentate gyrus(DG) and CA1 areas of hippocampus of young rats, so as to provide a direct morphological basis for studying the molecular mechanism of radiation cognitive impairment.Methods:21-day-old Sprague-Dawley (SD) rats were given a single dose of 10 Gy whole brain irradiation. The changes of cognitive function, dendritic spine density and morphological changes in DG and CA1 areas of hippocampus were observed 1 and 3 months after irradiation, and the expression of postsynaptic density protein (PSD95) was detected by Western blot.Results:The cognitive impairment was observed in young rats 3 months after irradiation. The density of dendritic spines in DG area of hippocampus was decreased significantly by 39.06% and 29.27% at 1 and 3 months after irradiation ( t=14.96, 12.35, P<0.05), respectively. The density of dendritic spines in the basal dendrites of hippocampal CA1 area was decreased by 33.40% ( t=10.39, P<0.05) 1 month after irradiation, but had no significant change at 3 months after irradiation. While the density of dendritic spines in the apical dendrites of CA1 region did not change significantly at 1 and 3 months after irradiation. In addition, the morphology of dendritic spines in DG and CA1 regions of hippocampus was dynamically changed after irradiation. The expression of PSD95 protein was decreased by 24.6% and 50.5% ( t=2.97, 9.27, P<0.05) at 1 and 3 months after irradiation, respectively. Conclusions:This study reported the density and morphological changes of dendritic spines in different brain regions of hippocampus of young rats after ionizing radiation, suggesting that PSD95 may participate in the occurrence of radiation-induced cognitive impairment by affecting the structure and morphology of dendritic spines and reducing synaptic plasticity.
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Objective To observe the effects of Wutou decoction(WTD)on Anxiety and Depression induced by the L5 spinal nerve ligation (SNL) mice. Methods The ICR male mice were randomly divided into sham,SNL,high-dose,medium-dose and low-dose group of Wutou decoction,and Pregabalin group,with 24 in each group. Except the sham group, SNL models were prepared in the remaining groups of mice. After successful modeling, the high, medium, and low dosages were administered with 12.60, 6.30, 3.15 g/kg of Wutou decoction,and pregabalin group was administered with 0.25 g/kg of pregabalin,and the sham group and the model group was given an equal volume of normal saline. All the administration was once per day, continuously last for 21 days. On the 7/14/21thdays after the operation, the depressive and eanxiety behavior were evaluated by the tests of the sugar water consumption, the open field and forced swimming detection. In addition, the number of the positive cells expressing the extracellular signal-regulated kinase (p-ERK) in hippocampus were analyzed on Day 7/14/21 in each group by Immunohistochemistry and the expression of both p-ERK and postsynaptic density protein 95 (PSD95) in the hippocampus were analyzed on Day 21 by Western blot. Results At 7, 14, and 21thday after administration, compared with the model group, the paw withdrawal mechanical threshold of mice(0.76 ± 0.21 vs.0.05 ± 0.03),(0.93 ± 0.33 vs.0.05 ± 0.01),(1.12 ± 0.20 vs.0.04 ± 0.01)in the high dose group of Wutou decoction respectively increased(P<0.01),and sugar consumption(1.86 ± 0.44 g vs. 0.84± 0.23 g), (1.84 ± 0.10 g vs. 1.02 ± 0.18 g), (1.63 ± 0.31 g vs. 0.75 ± 0.23 g) significantly increased(P<0.01),and immobility time 4 min after swimming(128.90 ± 35.27 s vs.180.30 ± 21.81 s),(125.50 ± 23.07 s vs.195.30 ± 27.70 s),(169.50 ± 23.07 s vs.207.50 ± 7.46 s)significantly decreased(P<0.01),and the retention time in the central area of the open field(35.35 ± 7.61 s vs.13.90 ± 2.27 s),(26.26 ± 3.61 s vs.13.08 ± 1.98 s),(24.04 ± 6.57 s vs.10.62 ± 3.38 s)significantly increased(P<0.01).After 21 days,the number of p-ERK positive cells in the high-dose group of Wutou decoction(11.00 ± 4.89 vs.33.67 ± 7.35)was siginificantly lower than that of the model group,and the hippocampus p-ERK protein(0.15 ± 0.09 vs.0.54 ± 0.04)siginificantly decreased,and the expression of PSD95 protein(0.32 ± 0.04 vs.0.57 ± 0.09)siginificantly decreased(P<0.01). Conclusions The Wutou decoction achieved significant anti-depressant and anti-anxiety effects,and regulated p-ERK expression levels of hippocampus in the late stage of NP.
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Objective To observe the effect of electroacupuncture (EA) at Baihui (GV20), Dazhui (GV14) and Shenshu (BL23) acu-points on cognitive function and the synapse of neurons in hippocampal CA1 in SAMP8 mice,to explore the mechanism of EA in the treat-ment of Alzheimer's disease(AD).Methods A total of 24 seven-month-old SAMP8 mice were randomly divided into model group(n=12) and EA group (n=12), and the same age SAMR1 mice were as control group (n=12).The EA group accepted EA at Baihui, Dazhui and Shenshu for 30 days.They were assessed with Morris maze test.The expression of synaptophysin(SYN)and postsynaptic density protein 95(PSD95)in hippocampal CA1 region were detected with immunohistochemistry.The morphology and density of synapse in hippocampal CA1 region was observed with transmission electron microscopy.Results Compared with the model group,the latency of Morris maze de-creased in EA group(P<0.05),the time staying in the quadrant of the platform increased(P<0.05),as well as the number passing the origi-nal platform(P<0.05),with the more expression of SYN and PSD95 in hippocampal CA1 region(P<0.001),and more and completed syn-apse.Conclusion EA can improve the learning and memory ability of SAMP8 mice by increasing the expression of SYN and PSD95 to pro-tect the ultrastructure of synapses in hippocampal CA1 region.
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AIM: To investigate the change of long-term potentiation ( LTP ) , and the expression of 5-hydroxytryptamine 1A receptor (5-HT1A receptor) and postsynaptic density protein 95 (PSD-95) in the hippocampus of the rats with posttraumatic stress disorder (PTSD), and to explore the mechanism of 5-HT1A receptor in the regulation of spatial memory in the PTSD rats.METHODS:Healthy adult SD rats (n=36) were randomly divided into control group and mod-el group, with 18 rats in each group.The rats in model group were treated with single prolonged stress to construct the mod-el of PTSD.Morris water maze ( MWM) was used to test the learning and memory ability .The LTP induced by high-fre-quency stimulation (HFS) was detected by electrophysiological method .The protein expression of 5-HT1A receptor and PSD-95 in the hippocampus was determined by Western blot and immunofluorescence .RESULTS: The MWM analysis showed that the latency of the rats searching for the underwater platform in model group was significantly longer than that in control group (P<0.01).The results of electrophysiological analysis showed that the amplitude of the evoked potential in both groups were significantly increased after HFS in the hippocampus , but that in model group was significantly lower than that in control group (P<0.01).The results of Western blot and immunofluorescence analysis showed that compared with control group, the protein expression of 5-HT1A receptor was obviously increased (P<0.05), while the expression of PSD-95 was obviously decreased in model group (P<0.05).CONCLUSION:The spatial memory impairment in the PTSD rats may be associated with the increase in the expression of 5-HT1A receptor and the decrease in the expression of PSD-95 in the CA1 region of hippocampus .
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Objective To study the effects of different types of exercise training on learning and memory, as well as on the expression of synaptophysin (SYP) and on postsynaptic density protein 95 (PSD-95) in rats in which a model of vascular dementia had been created.Methods Forty male Wistar rats were divided randomly into a voluntary exercise group (V-EX) , a forced exercise group (F-EX) , an involuntary exercise group (I-EX) , a vascular dementia group (VD) and a sham-operation group (Sham) , with 8 rats in each group.Two-vessel occlusion (2-VO) of the arteria carotis communis was used to create a model of vascular dementia in all of the rats except those in the sham-operation group.Beginning one week after the surgery, the V-Ex rats were free to run in a running wheel.The F-EX rats were forced to run 270 m a day in an electric wheel.The I-EX rats were stimulated to imitate the gait pattern of their forelimbs running at 9 m/min three times a day for l0 minutes each time.No special training was given to the rats in the other 2 groups.Three weeks after the surgery, their learning and memory were tested using a novel object recognition test.Immediately after the test, their prefrontal cortex was sampled and the expression of SYP and PSD-95 was detected using western blotting.Results The average novel object recognition indices of the rats in the V-EX, F-EX and I-EX groups were all significantly higher than that of the VD group.Average PSD-95 expression was also significandy higher than in the VD group.Conclusion Exercise, whether voluntary, forced or induced by functional electrical stimulation can improve learning and memory in vascular dementia, at least in rats.The mechanism is possibly that the training can increase the expression of PSD-95 in the prefrontal cortex, though not SYP.