| Introduction:Alzheimer’s disease(AD)is the most common dementia in clinic.It is associated with synaptic damage,mitochondrial abnormalities,inflammatory responses,hormonal changes and cell cycle disorders.Another important pathogenesis of AD is the degeneration of cholinergic neurons in central nervous system.Cholinergic neuron get its name because it can synthesize and release acetylcholine(ACh).The cholinergic system in cerebrum forms a large projection neural network which dominates multiple brain regions.Attention problem,learning disorder and memory deficit are the functional consequences of cholinergic neurons degeneration in basal forebrain.These neurons project nerve fibers that act as the main source of cholinergic energy in the cerebral cortex,hippocampus,olfactory bulb and amygdala.In particular,the nuclear magnetic resonance imaging(NMRI)results have shown parallel atrophy in the projection area of the cerebral cortex and hippocampus of the cholinergic neurons in patients with AD and mild cognitive impairment(MCI).These regions are related to learning memory and cognitive function.Analysis of the functional alternation of the cholinergic nervous system in the cerebral cortex and hippocampus can help to understand the development of AD.Since AD patients have diverse phenotypes,complex pathogenesis and long treatment cycle,drugs hitting a single target often yield undesired therapeutic effects.Searching natural drugs hitting multiple targets and with low toxicity is therefore of particular importance.China holds the advantages in this searching thanks to the country’s rich Chinese medicine resources and solid traditional Chinese medicine theories."Poisons hurt the brain neural network and the network damages hurt consciousness" is the ultimate mechanism of brain sentimental disorder,which could be applied to AD.Old age and infirmity lead to spleen and kidney deficiency,which will then cause "phlegm stasis that blocks brain" and dementia at last.To treat dementia,"detoxification and dredging collaterals"are preferred."Detoxification" means to get rid of damage factors,and "dredging collaterals"means to unclog the channels of Qi and blood.And these two actions can then "harmonize Ying-qi and Wei-qi" and gradually restore the overall function of the body.Panax notoginseng and Gardenia jasminoides are commonly used traditional Chinese medicines.Their main active ingredients are panax notoginseng saponins and geniposide,respectively,which have advantages in the treatment of central nervous system diseases."Jiedu Tongluo Decoction",the prescription compatibility of Panax notoginseng and Gardenia jasminoides,is commonly prescribed in clinical treatment of acute stroke since it effectively improves patient’s cognitive function.Therefore,whether the compatibility of the two traditional medicines can prevent AD and enhance the efficacy of each single drug while also reduce adverse reactions?If so,what is its mechanism of action?Objective:To investigate mechanism of action of the effective components as well as the compatibility of Panax notoginseng and Gardenia jasminoides in the cholinergic system of AD based on the background information;to explore new drug targets and provide data for clinical usage of Panax notoginseng and Gardenia jasminoides in AD treatment.Methods:In this study,we analyzed the functions of the effective components as well as the compatibility of Panax notoginseng and Gardenia jasminoides regarding learning and memory ability of APP/PS1 mice.Proteins related to this process were also analyzed.APP/PS1 mice were randomly divided into transgenic model group(Tg),Panax notoginseng saponins group(PNS),geniposide group(GP),and compatibility group(PNS+GP).And with non-transgenic littermate mice are included into the wild-type group(WT).The experiments were divided into three parts as follows:Experiment 1:Functional study of the effective components and the compatibility of Panax notoginseng and Gardenia jasminoides regarding learning,memory and cognitive impairment in APP/PS1 mice.Four-month-old APP/PS1 double transgenic mice were raised with food and water and weighed once per week.After 3-month prophylactic medication,the learning and memory ability of the mice was measured by step-down test analysis.Experiment 2:Functional study of the effective components and the compatibility of Panax notoginseng and Gardenia jasminoides regarding ACh level in APP/PS1 mice.After medication,cerebral cortex and hippocampus were collected and the ACh level was measured using acetylcholine test cassette.Experiment 3:Functional study of the effective components and the compatibility of Panax notoginseng and Gardenia jasminoides regarding the expression level of ACh-related protein in APP/PS1 mice.After medication,cerebral cortex and hippocampus were collected and the expression levels of four types of ACh-related proteins,i.e.,choline acetyltransferase(ChAT),acetylcholinesterase(AChE),high-affinity choline transporter(CHT1)and vesicular acetylcholine transporter(VAChT)were detected by Western blot(WB).Results:Experiment 1:The effective components and the compatibility of Panax notoginseng and Gardenia jasminoides significantly improved the learning and memory ability of APP/PS1 mice.Step-down test showed mice treated by GP and compatibility(PNS+GP)exhibited a significant longer latent period than the Tg group.During the medication process,mice in neither group showed any adverse reactions,and their body weights were gradually increased.Experiment 2:The effective components and the compatibility of Panax notoginseng and Gardenia jasminoides could regulate ACh level in APP/PS1 mice.In the cortex,the ACh level of the GP group showed an increasing trend compared with the Tg group.In the hippocampus,the ACh level of the PNS+GP group was significantly increased compared with the Tg group.Experiment 3:The effective components and the compatibility of Panax notoginseng and Gardenia jasminoides could regulate ACh-related proteins in APP/PS1 mice.In the cortex,WB results indicated significantly higher expression level of ChAT in GP group compared to the Tg group.Also,the expression level of AChE was significantly lower in the PNS group thart in the Tg group.In the hippocampus,the expression level of CHT1 was significantly higher in the PNS+GP group than that in the Tg group.Conclusion:"Jiedu Tongluo Decoction",as well as the effective components and the compatibility of Panax notoginseng and Gardenia jasminoides could effectively improve the learning and memory ability,regulate ACh level and expression level of ACh-related proteins in APP/PS1 double-transgenic mice,showing regulatory functions of cholinergic system to some extent. |
