Study On The Molecular Mechanisms Of β-asarone On Neural Synaptic Plasticity In Alzheimer’s Disease Model

BackgroundSynaptic plasticity was the pathological basis of learning and memory behavior change, quantity and the efficiency of synaptic changes could cause changes in synaptic plasticity, synaptic connection to strengthen or weaken, which was considered as the biological basis of learning and memory cell level. Glutamate receptors were the major excitatory neurotransmitter receptors in the central nervous system. It not only mediated excitatory synapses in the mammalian central nervous system fast transfer process, but also played a very important role in the neural development, neural cell death and synaptic plasticity (including learning and memory). ADDLs was the important pathological changes of brain in patients with AD, which could cause many kinds of neurotoxicity such as inflammation, injury of synaptic function in condensed form of A β fiber, also played a key role in the pathological process of AD, had become a hot target in the treatment of AD. The present study has showed that β-asarone had neuroprotective effect, but the influence of synaptic functional plasticity and the function or mechanism of glutamate neurotransmitter receptor had not been reported.ObjectiveAD is a progressive cognitive and memory impairment and neurodegenerative disease in the central nervous system. Acorustatarinowii Schott.(Shi Changpu in Chinese) has highest frequency for treating AD in Chinese medicine. The previous study had found that β-asarone was one of the main active components for protecting AD. However, the mechanism is unclear. This study is aim to investigate the effect of β-asarone on in vitro and in vivo models of AD and observe the influence of synaptic function plasticity and glutamate receptors, to clarify the mechanism of its neuroprotective effects and possible targets, for providing scientific basis for prevention and treatment of drugs on AD.MethodFrom the earlier nerve damage mechanism of AD, this study respectively investigated the timeliness of toxicity with AD cell model induced by ADDLs and Aβ1-42, established a stable cell model of AD. Based on the in vitro model, different dose of β-asarone was given for intervention to explore the effect and possible target through MTT、cell morphology and westerblot detection of synaptic protein presynaptic protein SYP and the AMPA receptor subunit GluR2. And with the APP-PS double transgenic mice, β-asarone was used as intervention method to evaluate the intervention effect of β-asarone through animal behavior test and detected the presynaptic protein synaptophysin, postsynaptic protein PSD93, PSD95and neural constitution glutamate receptor AMPA receptor subunits GluRl, GluR2and NMDA receptor subunit NR2A protein expression, to explore the possible mechanism of β-asarone for AD prevention and treatment.Result1. ADDLs,which used A β1-42by monomering in the polymerization temperature of4℃,24h. SDS-PAGE showed that the molecular weight is approximately15-20KD. Electron microscopy showed that diameter of about12NM of granular, spherical or ellipsoidal amorphous structure, can also be observed that the diameter of5-10nm, about20-30nm long curly branch-like structure. Not found fibrous aggregation structure.2. MTT results showed that the inhibition rate of A β10umol/L group for NG108-15cells and SH-SY5Y cell line was not only higher than the same molar concentration of ADDLs, even more higher than3times the molar concentration of ADDLs. And the30umol/L ADDLs showed differences damage effect in different cell lines.3.25umol/L (high dose group) β-asarone can significantly reduce the toxicity of A β-42after treatment24h, may have neuroprotective effect.6.25umol/L,12.5umol/L and25umol/L Asarone can improve cell damage morphology.12.5umol/L and25umol/L β-asarone significantly upregulated SYP expression (p<0.05) 4. Intragastric administration of low dose (containing crude drug2.12mg/100g*d) and middle dose (containing crude drug4.24mg/100g*d) of β-asarone can up-regulate the expression of double transgenic mice model of cerebral cortex PSD93(p<0.05), but high dose showed downregulation of PSD93(p<0.05)Conclusion1. β-asarone showed significantly reduce the toxicity of A β1-42in AD cell model, which may be related to the up-regulation of SYP expression.2. β-asarone significantly increased the double transgenic mouse cerebral cortex model of PSD93, SYP and GluR1expression, it suggested that the effect of β-asarone on euronal plasticity may be related to the expression of synaptic associated protein.