Studies On The Effects And Underlying Mechanisms Of The Novel Modified Kai-Xin-San In Treating Alzheimer’s Disease Based On The Regulation Of The Structure And Function Of Synapses

Objective:5×FAD mice were used as Alzheimer disease(AD)model mice,in order to study whether Kai-xin-san and novel Modified Kai-xin-san have pharmacological effects in treating AD,the mice were given Kai-xin-san and novel Modified Kai-xin-san by intragastric administration,and Donepezil hydrochloride was used as the positive control.To evaluate the pharmacological effects of the two formulas on the learning and memory ability of mice,behavioral tests such as open field test(OFT),novel object recognition(NOR),spontaneous T maze(TM),spontaneous Y maze(YM),morris water maze(MWM)were established.Western blotting and transmission electron microscopy(TEM)were applied to study the APP cleavage C99,postsynaptic protein PSD-95 levels and structure change of synapses in hippocampus.Long-term potentiation(LTP)of hippocampus CA1 schaffer collateral pathway were recorded to compare the synaptic function and its link with the structure to reveal the mechanism of the novel Modified Kai-xin-san in treating AD.We want to explore whether the effects of novel Modified Kai-xin-san is better than Kai-xin-san in treating AD animal models and we also want to know the related underlying mechanism.Methods:3-4 months’ old 5xFAD mice(half male and female)were randomly divided into 4 groups:AD model group(5xFAD),Donepezil group(5xFAD+DP)and Kai-xin-san group(5xFAD+KXS),Modified Kai-xin-san group(5xFAD+MKXS).And littermate WT C57BL/6 mice were used as normal control(WT).From 3-4 months’old,5xFAD mice were given Kai-xin-san,novel Modified Kai-xin-san and Donepezil Hydrochloride by intragastric administration daily until death,and WT was given equal volume vehicle(Milli-Q water)instead.After 3 months’ intragastric administration,behavioral test such as OFT,NOR,T/Y maze and MWM were used to evaluate the learning and memory ability.After behavioral test,Western blotting was used to examine the APP cleavage C99 peptide and PSD-95 levels in hippocampus.TEM was used to observe the structure of synapses in CA1 region.Finally,Patch clamp was used to record the LTP of Schaffer collateral pathway.Results:5×FAD mice showed apparently cognitive decline compared with WT mice.Compared with 5×FAD group mice,Donepezil,Kai-xin-san and novel Modified Kai-xin-san can increase the exploration time on novel object(NOR),novel arm(T/Y maze),target crossings(MWM),50-60 min fEPSP sclope of LTP,PSD95 levels in WB,synapses vesicles numbers and PSD area under TEM observation,and decrease the escape lantency(MWM),APP cleavage C99 peptide levels in WB and the mean diameter of SV.But only novel Modified Kai-xin-san can increase the exploration time in target quadrant.And novel Modified Kai-xin-san has better effects than Kai-xin-san in target crossings(MWM),50-60 min fEPSP in LTP,APP cleavage C99 peptide and PSD-95 levels in WB,mean diameter and vesicle numbers of SV in TEM observation.Conclusion:Kai-xin-san and novel Modified Kai-xin-san can alleviate the learning and memory defiency in 5×FAD mice,and novel Modified Kai-xin-san has better effects than Kai-xin-san.The mechanism may be related to their effects on decreasing the Aβ levels and protective effects on the structure integrality of the synapses,and thus these effects can rescure the synaptic function in AD.