Effect And Mechanism Of Radix Bupleuri Combined With Radix Paeoniae Alba On Susceptibility To AD In Rats Induced By Chronic Stress

ObjectiveAlzheimer’ s disease(AD)is a progressive neurodegenerative disease that is currently not cured by drugs.Studies have shown that the production of beta-amyloid(A β)has increased in the early stage of mild cognitive impairment.Chronic stress can increase the risk of AD,causing dysfunction of the nervous system of the body,leading to the accelerated aging process and learning and memory impairment.Therefore,the focus of AD research should shift from dementia to pre-dementia,from treatment to prevention.The prevention and treatment of AD from the perspective of hepatic regulation has a theoretical basis and practical significance,and studies have shown that the application of Shugan treatment and the application of liver-dissolving drugs can alleviate AD symptoms and interfere with degeneration and degeneration of hippocampal neurons.In this study,the chronic unpredictable mild stimuli(CUMS)model was used to investigate the effect and mechanism of Shugan classic compatibility with Radix Bupleuri-Radix Paeoniae Alba pairs on prevention and treatment of AD in chronic stress-induced rats.MethodThe chronic unpredictable mild stimuli(CUMS)modeling method was used to observe the behavioral indicators,including the sugar water preference experiment,the open field experiment,and the Morris water maze,before the start of modeling and at 2,4,6,8,and 10 weeks after modeling,and then the rats were sacrificed to take brain tissue,thioflavine T.The expression of A β and Tau protein phosphate in hippocampus was detected by staining.The CUMS model was established and randomly divided into CUMS group,CUMS+fluoxetine group(Fluoxetine),CUMS+Radix Bupleuri-Radix Paeoniae Alba pairs-treated low-dose group(Low),CUMS+Radix Bupleuri-Radix Paeoniae Alba pairs-treated high-dose group(High)according to the result of sugar water water preference rate in the sixth week of modeling.There is also a control group(Control)that is not modeled.According to the literature,fluoxetine was selected as a positive drug and administered by intragastric administration at 5 mg/(kg·d).Radix Bupleuri-Radix Paeoniae Alba pairs is decocted to a concentration of lg/ml in a ratio of 1:1,the low dose of 3g/(kg·d),high dose of 9g/(kg·d),and group after the sixth week.The group was given 4 weeks of treatment for the corresponding drug.After the end of drug treatment(ie,the 10th week of the experiment),including the sugar water preference experiment,the open field experiment and the Morris water maze were observed,rat brain tissue was taken,and Western Blot was used to detect the expression of A β and Tau protein in the hippocampus.A β precondition protein(APP)Beta-amyloid precursor protein cleavage enzyme(BACE),glycogen synthase kinase-3(GSK3 3),and brain-derived neurotrophic factor(BDNF)and its receptor tyrosine kinase B(TrkB)and cyclophosphamide Effect of glycoside response element binding protein(CREB)expression.The number of hippocampal neurons was detected by Nissl staining,and the expression of C/EBP β in the hippocampus was detected by immunohistochemistry.Result1.Chronic stress can increase AD susceptibility in ratsThe results of behavioral experiments at the 2nd and 4th weeks showed that the growth rate of the CUMS group was slower than that of normal group(P<0.01),but there were no significant changes in sugar preference rate,total distance,rest time,latency of Morris water maze experiment and the number of times of crossing the original platform.At the 6th week,the weight of the CUMS group decreased significantly(P<0.01),the sugar preference rate decreased(P<0.01),the total distance decreased(P<0.05),and the rest time increased.On the 5th day of positioning navigation experiment,the latency of CUMS group began to change(P<0.05).However,the number of times of traversing the original platform did not change in the space exploration experiment.Until the tenth week of the experiment,the weight of CUMS group decreased(P<0.01),sugar preference rate decreased(P<0.01),total distance decreased(P<0.01),rest time increased,positioning navigation experiment and space exploration experiment showed significant changes(P<0.05).It suggested that CUMS model was successful and depressive symptoms and cognitive changes were found in CUMS group.The deposition of Aβ and phosphorylation of Tau protein are the pathological characteristics of AD.The results show that CUMS can induce the increase of Aβ immersion and phosphorylation of Tau,but this change occurs in the 10th week.These results suggest that cognitive changes can occur only after 10 weeks of CUMS modeling,and depression-like symptoms appear before cognitive changes.2.Effect and mechanism of Radix Bupleuri-Radix Paeoniae Alba pairs on preventing and susceptibility to AD induced by chronic stressCompared with CUMS group,Radix Bupleuri-Radix Paeoniae Alba pairs showed an upward trend in body weight,a significant increase in sugar preference rate(P<0.05),an increase in total distance(P<0.01),a decrease in rest time and a decrease in serum CORT content(P<0.01),suggesting that Radix Bupleuri-Radix Paeoniae Alba pairs could improve depression-like symptoms induced by CUMS stimulation in rats.Compared with the CUMS group,the latency of the low-dose group and the high-dose group of the Radix Bupleuri-Radix Paeoniae Alba pairs was significantly shortened,similar to the trend of the blank group.In the space exploration experiment,the number of rats crossing the original platform in the low and high dose groups of Radix Bupleuri-Radix Paeoniae Alba pairs was significantly higher than that in the CUMS group(P<0.05).The results showed that Radix Bupleuri-Radix Paeoniae Alba pairs could promote the formation and consolidation of spatial memory in rats.WB was used to detect the effects of Radix Bupleuri-Radix Paeoniae Alba pairs on phosphorylation of AD marker Tau protein and Aβ in the hippocampus of Wistar rats.Compared with the CUMS group,the ratio of p-Tau/Tau in the administration group decreased,and the ratio of p-Tau/Tau in the high-dose group decreased significantly(P<0.05),and the ratio of Aβ in the low-dose group and the high-dose group decreased significantly(P<0.05),which indicated that the ratio of Radix Bupleuri-Radix Paeoniae Alba pairs could reduce the production of Aβ and phosphorylation of Tau protein.Further studies showed that compared with the CUMS group,the expression of APP in the hippocampus of rats in low and high dose groups was significantly decreased(P<0.01),which reversed the decrease of BACE in the hippocampus of rats in CUMS group(P<0.05),and the expression of GSK3 β in high dose group had a downward trend.In addition,the results also showed that the expression of C/EBP β in the hippocampus was decreased(P<0.05),and the survival of neurons was increased(P<0.05).The results showed that the TrkB expression of Radix Bupleuri-Radix Paeoniae Alba pairs was up-regulated in low and high dose groups.The expression of CREB was up-regulated in high dose group.High-dose therapy significantly reversed the down-regulation of BDNF in the hippocampus of CUMS rats(P<0.05).These results suggest that Radix Bupleuri-Radix Paeoniae Alba pairs can down-regulate the expression of C/EBP β,regulate the wrong splicing of APP,decrease the phosphorylation of Tau protein,up-regulate the expression of BDNF and increase the number of neurons.Conclusion1.Chronic stress can increase the susceptibility of AD in rats.2.Radix Bupleuri-Radix Paeoniae Alba pairs can improve the AD susceptibility of rats induced by chronic stress,which may be achieved by multiple targets.Radix Bupleuri-Radix Paeoniae Alba pairs can down-regulate the expression of C/EBP β and regulate the mis-shock of APP,reduce the phosphorylation of Tau protein,and up-regulate the expression of BDNF.