| Aim: Alzheimer’s disease(AD)is the most common cause of dementia globally,the fourth cause of death after cardiovascular disease and cancer.The number of patients approximately 36 million people currently and may be increased to 115 million by 2050.The neuropathology of AD consists of the accumulation of amyloid β(Aβ)as amyloid plaques and phosphorylated tau aggregation to form neurofibrillary tangles.Aβ and tau oligomers,as well as amyloid plaques and neurofribrillary tangles(NFTs),share many structural and biophysical properties,such as a high β-sheet content,resistance to proteolytic degradation and lead to neuronal toxicity.Nowadays,the frst-line treatment for AD is the application of acetylcholinesterase inhibitors.However,acetylcholinesterase inhibitors are basically anti-symptomatic for a limited aspect of AD pathology and in the long-term treatment is facing an ineffective dilemma.Using APP / PS1 transgenic mouse as AD model,the aim of this study was to evaluate the long-term treatment effect of TSG on the learning and memory of APP / PS1 transgenic mice(referred to APP / PS1 mice),and then to observe the effect of TSG on the pathology of AD.Then the micro RNA was analyzed by gene chip to predict the possible target of drug action and preliminary validation.Methods:(1)group and administrationBefore administration: Wild Type mice,APP / PS1 mice,5 months old.Long-term administration : control group: wild type mice,Wild Type mice + TSG(100 mg / kg / d);mode group: APP/ PS1 mice;medicament group: APP/ PS1 mice + TSG(50 mg / kg / d)mice,APP / PS1 mice + TSG(100 mg / kg / d)mice,APP/ PS1 mice + donepezil(1 mg / kg / d).From 5 months to 17 months of age.(2)Behavioral examination: Morris water maze test and new object recognition test to detect mouse spatial learning and memory function,independent activity detection of mouse activity.(3)The deposition of β-amyloid plaques was observed by sulfide staining and immunohistochemistry.The contents of Aβ42 in the brain were detected by ELISA.(4)Western blot was used to detect APP,the changes of ADAM-10 and BACE-1,the expression of β-amyloid metabolic enzymes and synapsin-1,synaptophysin,synaptogmin and PSD95 in the cortex and hippocampus.(5)Selecting the hippocampus of the control group: Wild Type mice;model group: APP / PS1 mice;drug treatment group: APP / PS1 mice + TSG low dose(50 mg / kg / d)and APP / PS1 mice + donepezil(1 mg / kg / d),5 / group,Micro RNA chip was used to screen biomarkers and drug targets,then verified by QPCR.(6)Statistical method: The experimental data of each group were expressed as mean ± SE(standard error),the number of samples between groups was compared by one-way ANOVA,and the multivariate analysis of variance was used to Morrise water maze;With P <0.05 for the difference was significantly.Results:(1)learning and memory and activityCompared with the wild type mice,the escape latency of APP / PS1 mice at 17 months of age was significantly prolonged in the Morris water maze test,and the discrimination index of the new object recognition experiment was reduced.The APP / PS1 mice in 5 months had given TSG 12 Month to 17 months of age,escape latency was significantly shorter than 17 months of APP / PS1 mice in the Morris water maze test,at the new object recognition experiment improve the discrimination index.There was no difference between the groups in the result of independent activity.(2)APP and its metabolic enzymes Compared with the wild type mice,the APP were significantly increased in APP / PS1 mice,and the expression of APP was significantly decreased after administration of TSG,in the cortex and hippocampus.The expression of BACE-1 and PS1 in the model group was significantly higher than the control group(P <0.05).The expression of BACE-1 and PS1 in the 17 months of APP / PS1 mice was significantly decreased after administration of TSG.There was no significant difference in the expression of ADAM-10 between the 17-month-old APP/PS1 mice compared with the wild-type control group in the cortical region.There was no significant difference between NEP and IDE in all groups.(3)Amyloid plaque deposition and the content of Aβ42 in the brain Compared with the wild-type control group,the thymosin staining and immunohistochemistry showed that the amyloid plaques in the brain of 17 months of APP/PS1 mice were significantly increased,and the number of amyloid plates was significantly reduced after administration of TSG area In the cortex and hippocampus regions.Compared with the Wild Type mice,ELISA results showed that 17 months of APP / PS1 mice,the count of Aβ42 was significantly higher in the brain.After giving TSG,Aβ42 can be significantly reduced,especially the level of insoluble Aβ42.(4)Proteins correlate synaptic The synaptophysin expression in APP / PS1 mice was significantly decreased in the cortex and hippocampus compared with the Wild Type mice in the same age group,and the expression of synaptophysin was significantly increased after administration of TSG.Compared with wild type mice in the same age group,the expression of p-synapsin in the cortex of 17 months of APP / PS1 mice was significantly decreased,and the expression of p-synapsin was significantly increased after administration of TSG,and no significant change in the hippocampus.There was no significant difference between PSD-95 and synaptotagmin in all groups.(5)The change of Micro RNA Micro RNA microarray real-time quantitative PCR results show,the mi R-26a-5p expression level in the hippocampus of APP/PS1 mice was decreased compared with the 17-month-old mice wild-type mice in the same age,and the expression level of mi R-1971 and mi R-204-3 were increased,they all statistically significant.Micro RNA microarray real-time quantitative PCR results show,compared with the same age Wild Type mice,in the hippocampus region,17 months of APP / PS1 mice mi R-2861,mi R-542-5p,mi R-141-3p,mi R-200c-3p expression level increased,given the TSG expression level was significantly reduced.Conclusion: TSG can improve the learning and memory function of APP / PS1 mice,which is Alzheimer’s disease model,significantly shorten the escape latency in Morris water maze,increase the discrimination index in new object recognition,and its mechanism includes:(1)By reducing the expression of APP in brain,β-secretase(BACE-1),and γ-secretase(PS1)to reduce Aβ production.(2)TSG can affect the expression of Aβ42 and reduce the neurotoxicity of Aβ.(3)TSG can affect the protein related to synapsin,inscrease the expression of synaptophysin and p-synapsin.(4)TSG plays a role at the level of micro RNA,by influencing the target gene,that impact the proteins involved in the synaptic signal transduction process,which affects protein expression during AD development.This study provides experimental support for the development of AD therapeutic drugs providing evidence for the long-term treatment of AD in Chinese medicine,which is of great value. |
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