| Background Alzheimer disease(AD)is one of the most common neurodegeneration diseases,containing two types – familial Alzheimer disease(FAD)and sporadic Alzheimer disease(SAD).FAD only accounts for 1% of the AD morbidity,which is mainly related with amyloid precursor protein(APP),presenilin(PSEN)and Apolipoprotein E(Apo E)and Tau;SAD occurs accompanied with aging and is more likely related with cerebrovascular disorders,neuroinflammation.There are several AD hypothesis,such as A? hypothesis,Tau hypothesis,neurovascular hypothesis,Presenilin loss-of-function hypothesis.They illustrate the mechanism of AD processing with different angles and causing factors.However,they still cannot fully elaborate the mechanism of AD;so far,the curative effects of drugs(mainly compounds)targeted on clearance of amyloid plaques and reducing the production of A? are almost out of expectation.On the other hand,according to traditional Chinese medicine,the hypothesis of"detoxication and collateral-dredging" refers that it is turbid toxins block collateral,leading to disability of qi and blood distribution.When the tubid toxins block brain collateral,the spirit is out of control and results of dementia.The Academican Yongyan Wang pointed that"toxic factor" and"collateral disease" can be seriously considered as an entry point of a study.Due to the aim of detoxication and collateral-dredging,put detoxication in an important position,and accompanied with nurishing and dredging collateral.Based on this viewpoint,the combination of geniposide(GP)and Panax noto-ginseng(PNS)(the two combination also called Tong Luo Jiu Nao)is raised.For one side,geniposide is the monarch drug to detoxicify toxic factors,such as amyloid plaques;for the other side,PNS is the ministerial drug to dredge brain collateral,such as cerebral vascular disorders.This is also a combination of traditional Chinese medicine and western medicine.In addition,the drug of GP and PNS has been used to treat acute stroke in clinic,and also improves cognition whose with dementia.Furthermore,in our group,we have proved the drug has a neuroprotective role in many different AD-like animal models.In order to explore its mechanism,we used two different animal models following two different pathological mechanisms.One is APP/PS1 transgenic mice under the"A? hypothesis",and the other is PS1 D385 A knockin mice under the"Presenilin loss-of-function hypothesis".We try to explore whether the combination of geniposide and PNS can reduce the number of amyloid plaques,and the modulation on cerebrovascular.Objective Through two different animal models,explore the efficacy of GP and PNS,and try to find a new drug target of AD.Method There are four parts for this study:Experiment 1: The analysis of this combination on the improvement of impaired cognition of APP/PS1 transgenic mice.The drug administration starts from 4-month age,and lasts for 3 months.During treatment period,we monitored body weight change every week.Step-down test and Morris Water Maze are used to evaluate the learning and memory capability.Also,the body weight change is gradually increased in each group.Experiment 2: The effects of the combination on amyloid plaques and cerebral blood flow of APP/PS1 transgenic mice.Chemical staining is used to analysis the number and distribution of amyloid plaques in brains.Laser-Doppler flowmetry(Peri Flux System 5000)is used to measure their cerebral blood flow.Experiment 3: The analysis of PS1 D385 A KI mice.Southern analysis has been used to test its genomic DNA;HE staining has been used to detect the morphology of developing brains;Western of CD31 has been used to analysis the angiogenesis;and Brd U immunochemistry has been used to test the proliferation of neural progenitor cells.Experiment 4: Initial exploration of the effects of this combination on cerebrovascular amyloid plaques and abnormal angiogenesis of PS1 D385 A KI/+ adult mice.Immunofluorescence is used to analysis amyloid plaques.Western and immunofluorescence are used to analysis angiogenesis.Results Experiment 1: The combination can improve the cognition of APP/PS1 transgenic mice.In Step-down test,the combination significantly improves the memory duration compared with Tg mice;in Morris Water Maze,the target quadrant occupancy is significantly longer in the combination group compared with transgenic mice.Experiment 2: Under the treatment of the combination,amyloid plaques deposition is significantly reduced compared with Tg mice,especially in terms of the larger plaques.GP and PNS significantly increases cerebral blood flow compared with transgenic mice.Experiment 3: PS1 D383 A KI/KI mice show postnatal lethality,accompanied with skeleton abnormal,developmental retardation of brain and severe hemorrhage;though the phenotype of KI/+ mice is identical to their littermate wild-type control,the expression of CD31 protein is significantly higher compared with wild-type mice.Furthermore,KI/+ adult mice show severe cerebrovascular amyloid plaques and abnormal angiogenesis observed in both hippocampus and cortex.Basically,PS1 D385 A KI mice accord with the"Presenilin loss-offunction hypothesis",accompanied with dysfunction of PS1 endoproteolysis and abolishment of ?-secretase activity.Experiment 4: In PS1 D385 A adult mice,the combination of GP and PNS significantly eliminates cerebrovascular amyloid plaues and inhibits angiogenesis in both cortex and hippocampus.Furthermore,the combination can significantly reduce the abnormal accumulation of PS1 full-length protein,and recover part of ?-secretase activity.Conclusion The "detoxification and dredging collaterals" formulae can significantly reduce the deposition of amyloid plaques;under two different animal models,the combination has a two-ways modulation on angiogenesis.In APP/PS1 transgenic mice,the combination can recover the cerebral blood flow and promote angiogenesis;in PS1 D385 A KI mice,the combination can reduce the abnormal angiogenesis in both cortex and hippocampus. |
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