Proteomics Study Of Tianqi Yizhi Granule On Improving The Learning And Memory Function Of Alzheimer's Disease Rats

Objective:To observe the effects of Tianqi Yizhi granules(TYG)on cognitive function of Alzheimer’s disease(AD)rats,as well as its effects on the protein expression of cortical and hippocampal,to explore the brain protective effect and pharmacological mechanism of TYG on AD model,so as to provide the research basis for the treatment of Alzheimer’s disease by TYG.Methods:1.90 SD male rats(4 months old)were randomly distributed into control group(sham-operation),AD model group,HupA group,and the high,medium and low dose of TYG groups.In addition to the control group,AD models were prepared by A∞1-42 injection in lateral ventricles.2.One week after operation,the high,medium and low dose TYG groups were given 0.76、0.38 and 0.19g/kg by gavage for 40 consecutive days,and rats in HupA group were given 0.02mg/kg HupA,in control or model groups were given equal amounts of saline by the same method.3.After administration,Morris water maze was applied to conduct the positioning cruise experiment and the space exploration experiment.The escape latency and the time staying in the target quadrant were compared between groups,and the cognitive learning ability of each group was compared.4.Quantitative proteomic TMT(Tandem Mass Tag)labeling technique was applied to analyze the differential expression of proteins in rat cerebral cortex and hippocampus.Bioinformatics analysis of differential proteins was further performed using Uniprot,PANTHER and STRING10.5 databases to study the possible target and therapeutic mechanism of TYG.5.The differentially expressed proteins PC(Pyruvate carboxylase),MDH2(Malate dehydrogenase)and FADD(FAS-associated death domain protein)were verified using Western Blot.Results:1.Morris water maze experiment results:①Hidden platform tests:Compared with the control group,the escape latency and distance of rats in AD model group were significantly extended(P<0.01).Compared with the model group,the escape latency and distance were significantly decreased in the medium,high dose TYG group and the HupA group(P<0.05).②Probe trials:The percentages of time and distance of model group stay in the target quadrant were significantly decreased when compared with control group(P<0.01).The percentages of time and distance of the medium,high dose TYG and the HupA group stay in the target quadrant were significantly increased when compared with model group(P<0.01).2.TMT quantitative proteomics:TYG has a significant effect on the expression of 37 AD-related proteins in the cerebral cortex and hippocampus of rats(P<0.05),among which over 50%were related to energy metabolism and anti-apoptosis,while others are related to neural transmission,neural development,cytoskeleton and Aβ formation.The expression of these proteins increased except for proteins related to apoptosis and the Aβformation.3.Western Blot:Pc and Mdh2in the high-dose group of TYG were significantly increased compared with the model group(P<0.01).Fadd of the middle and high dose groups of TYG was significantly increased than model group(P<0.01),and these results were basically consistent with the results of proteomics research.Conclusion:TYG can improve the cognitive dysfunction induced by Aβ1-42in AD rats.Its therapeutic mechanism may involve the regulation of various processes,mainly through the promotion of energy metabolism and neural transmission,anti-apoptosis and other methods.