ABSTRACT
OBJECTIVE：To study the regulatory effects of stilbene glucosid e（TSG）on c-Jun N-terminal kinase （JNK）and protein phosphortase 2B（PP2B）in APP/PS1/Tau transgenic dementia （3×Tg-AD）mice，and to explore its potential mechanism of anti-Alzheimer’s disease （AD）. METHODS ：Totally 45 male 3×Tg-AD mice were randomly divided into model group ，positive control group （huperzine A ，0.15 mg/kg），TSG low-dose ，medium-dose and high-dose groups （0.033，0.1，0.3 g/kg），with 9 mice in each group. Another 9 normal male C 57BL/6J mice were included into normal control group. Administration groups were given relevant medicine intragastrically ，once a day ，for consecutive 60 d. Normal control group and model group were given constant volume of normal saline intragastrically. After medication ，Morris water maze experiment was used to test the spatial learning and memory ability of mice in each group ；Nissl staining was used to observe the changes of Nissl bodies in cerebral cortex and hippocampus ；mRNA and protein expressions of JNK and PP 2B were detected by qRT-PCR and Western blotting assay. RESULTS：Compared with normal control group ，the escape latency was significantly prolonged （P＜0.01），the retention time of the original platform quadrant was significantly shortened （P＜ and the times of crossing the platform was significantly reduced in model group （P＜0.01）；the number of Nissl bodies in cerebral cortex and hippocampus was significantly 729011126@qq.com reduced，the staining was slight ；the relative expressions of JNK mRNA and protein were significantly increased （P＜ 0.01），and the relative expressi ons of PP 2B mRNA and protein were significantly decreased （P＜0.01）. Compared with model group ，the escape latency was significantly shortened in positive control group and TSG groups （P＜0.01）；the retention time of the original platform quadrant was significantly prolonged （P＜0.01）；the times of crossing the platform was significantly increased （P＜0.01）；the number of Nissl bodies in cerebral cortex and hippocampus was increased significantly ，the staining was heavy ；the relative expression of JNK protein was significantly decreased（P＜0.05 or P＜0.01），the relative expressions of PP 2B mRNA and protein were significantly increased （P＜0.01）， while the relative expression of JNK mRNA was significantly decreased in TSG high-dose group （P＜0.05）. CONCLUSIONS ：TSG can improve the learning and memory ability and neuronal damage of 3 × Tg-AD mice. The mechanism may be related to down-regulating the transcription and expression of protein kinase JNK ，up-regulating the transcription and expression of protein phosphatase PP 2B.
ABSTRACT
Objective To observe the effects of adiponectin (APN) on anxiety-and depression-like behaviors occurred in APP/PS1/tau triple transgenic Alzheimer's disease (3xTg-AD) model mice and investigate the possible mechanism.Methods The 9-month-old 3xTg-AD mice and wild type (WT) mice were randomly divided into four groups (n=8 for each group):WT+Saline,WT+APN,3xTg-AD+Saline and 3xTg-AD+APN groups.The mouse was chronically intracerebroventricular injection of APN or saline under free moving condition.Elevated plus maze task was used to evaluate the anxiety-like behaviors.Sucrose preference test and tail suspension test were used to evaluate the depression-like behaviors.Western blot was used to detect the protein expression levels of p-AMPK,AMPK,p-GSK-3β (Ser9),GSK-3β and SIRT1 in the hippocampus of each mouse.Results In the elevated plus maze test,the time percentage spent in open arms of 3xTg-AD+Saline mice was ((4.2±2.7) ％),which significantly lower than that in WT+Saline group ((10.1±4.1)％) (q=4.349,P＜0.01) and in 3xTg-AD+APN group ((9.7±3.3)％) (q=4.065,P＜0.01).In the sucrose preference test,the sucrose preference percentage in 3xTg-AD+Saline group((48.8±5.3) ％) was lower than that in WT+Saline group ((60.9±6.7) ％) (q=4.522,P＜0.01) and in 3xTg-AD+APN group ((59.3±6.2)％) (q=3.911,P＜0.05).As for tail suspension test,the immobility time percentage in 3xTg-AD+Saline group((40.7±9.9)％) was higher than that in WT+Saline group ((27.1±4.8)％) (q=5.257,P＜0.001) and in 3xTg-AD+APN group ((31.4±6.0)％) (q=3.624,P＜0.05).The result of Western blot showed that there was no significant difference in expression level of AMPK and GSK-3β among four groups.However,compared with that in WT+Saline group,the expression levels of p-AMPK (q=3.586,P＜0.05),p-GSK-3β (Ser9) (q=3.125,P＜0.05),and SIRT1 (q=3.044,P＜0.05) in 3xTg-AD+Saline group were significantly decreased.In addition,compared with that in 3xTg-AD+Saline group,the expression levels of p-AMPK (q=3.374,P＜0.05) and p-GSK-3β (Ser9) (q=3.063,P＜0.05) in 3xTg-AD+APN group were obviously up-regulated without affecting the SIRT1.Conclusion Adiponectin can effectively alleviate the anxiety-and depression-like behaviors of 9-month-old 3xTg-AD mice by up-regulating the protein expression of p-AMPK and p-GSK-3β (Ser9) in the hippocampus.
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Objective To investigate the early onset of learning and memory function of 4-month-old APP/PS1/Tau Alzheimer' s disease (3×Tg-AD) model mice and explore the pathogenesis of AD in early stage through evaluating neuron excitability and BKCa channel activity in cingulate cortex pyramidal cells.Methods Ten 4-month-old male 3×Tg-AD mice and matched ten wild type (WT) mice.Behavior was tested with the novel object recognition task to observe the ability of learning and memory.Whole-cell patch-clamp recordings were performed to assess the excitability of cingulate cortex pyramidal cells in terms of resting membrane potential and frequencies of spikes evoked by current injection.A train of five pulses of depolarizing currents were injected at 100 Hz to assess the spike width,which was used as an index for BKCa channel activity.Results Compared with the WT group (0.72±0.03),the novel object recognition index significantly decreased in 3 × Tg-AD group (0.55 ± 0.04) (P =0.004).Compared to the WT group((-66.03±0.43) mV),the resting membrane potential in cingulate cortex neurons of 3×Tg-AD group((-62.31±0.54)mV) was significantly depolarized(P=0.000).In contrast to WT group,the action potential firing frequencies evoked by depolarizing current injections were higher in neurons from 3×Tg-AD group(P=0.000),demonstrating that excitability of cingulate cortex neurons was elevated by intracellular Aβ.Spikes were broader in the 3×Tg-AD group than those in the WT group(P＜0.01).Suppression of BKCa channels in cingulate cortex neurons from the 3×Tg-AD group was confirmed on the basis of the spike half-width,since BKCa channels affect the descending phase of spikes.Conclusion Compared to WT mice,4-month-old 3×Tg-AD mice are impaired in learning and memory.The suppression of BKCa channels by intracellular Aβ leads to increase of excitability in cingulate cortex pyramidal cells.