Neuroprotective Effects Of Swertisin On Aβ_25-35-induced AD Mode

Alzheimer’s disease is a neurodegenerative disease that occurs frequently in the elderly.The main manifestations are cognitive decline and memory impairment.AD seriously affects the physical and mental health of patients,and causes huge economic burden on individuals,families and society.Therefore,the prevention and treatment of AD has become one of the problems that society urgently desires to solve.Swertisin is one of the main active ingredients in Ziziphi Spinosae Semen.It has a wide range of pharmacological effects such as anti-inflammatory,antioxidant and enhancement of learning and memory.Previous studies have shown that: in the central nervous system,swertisin inhibited the release of pro-inflammatory factors and the activity of oxidase,it played a protective role in the damage of neurodegenerative diseases;In animal behavior experiments,swertisin improved learning and memory impairment and enhanced learning and memory tasks in mice.These studies indicated that the protective effect of swertisin may be related to anti-inflammatory and antioxidant,but the mechanism was still unclear.Therefore,this paper is based on the Aβ_25-35 cascade and neuroinflammation theories,combined with the neuroprotective effect of endocannabinoid 2-AG against inflammation,using Aβ_25-35-induced AD model as the research object,combined with LC-MS,western blotting,patch-clamp technology and other modern biochemical techniques and methods to explore the neuroprotective effect and mechanism of swertisin.The specific research are as follows: 1.The protective mechanism of swertisin on Aβ_25-35-induced AD model of hippocampal slicesMouse hippocampus was acutely isolated and administered,Aβ_25-35 aggregates acted on hippocampal slices to establish AD injury model.The results showed that: 1)swertisin increased the content of endogenous 2-AG,it was mainly achieved by inhibiting the metabolism of 2-AG: inhibited the 2-AG-specific degradation enzyme MAGL protein overexpression;Reduced the overexpression of COX-2 protein induced by Aβ_25-35 and inhibited COX-2 enzyme activity with IC50 value of 55.4 n M;2)Swertisin improved Aβ_25-35-induced neuroinflammatory factors（IL-6,IL-1β）and apoptosis（Bax and Bcl-2）.However,the slices were pre-incubated with SR1（blocker of CB1R）,the improvement effects disappeared,so it was concluded that swertisin improved Aβ_25-35-induced inflammation and apoptosis through CB1 receptor;3)exogenous addition of 2-AG inhibited the overexpression of TNF-α induced by Aβ_25-35,which is mutually consistent with the results of endogenous 2-AG;4)Swertisin disaggregated Aβ_25-35 aggregates by dynamic light scattering;5)Swertisin improved Aβ_25-35-induced learning and memory impairment by recording field excitatory post-synaptic potentials in the hippocampal CA1 region and using patch clamp technology with LTP as an indicator;6)Swertisin inhibited the overexpression of p-NF-κB protein induced by Aβ_25-35,it had no effect on the expression of NF-κB;Blocking CB1 R,effect disappeared;These indicated that the neuroprotective effect of swertisin was achieved through the NF-κB signaling pathway dependent on the CB1 receptor.2.The protective mechanism of swertisin on Aβ_25-35-induced AD model of primary hippocampal neuronsAβ_25-35 induced primary hippocampal neurons to build AD model,the protective effects of swertisin on Aβ_25-35-induced primary hippocampal neurons AD model was further evaluated by CCK-8 method,western blotting,and Elisa kits.The results showed that swertisin significantly inhibited Aβ_25-35-induced cell death and improved cell survival rate;swertisin in primary hippocampal neurons inhibited 2-AG metabolism to exert the neuroprotective effect of inflammation and anti-apoptosis.These neuroprotective effects had achieved through the NF-κB signaling pathway via CB1 receptor.3.Effect of swertisin on AD model of BV-2 microglia cells induced by Aβ_25-35Aβ_25-35-induced BV-2 microglial cells were selected to establish AD model,and the protective effects of swertisin on Aβ_25-35-induced AD model was studied by MTT method and flow cytometry.The results showed that swertisin did not improve the cell activity of BV-2 cells injury induced by Aβ_25-35;The results showed that the effect apoptosis of BV-2 microglia was also not improved.In summary,studies have shown that swertisin has a certain protective effect on Aβ_25-35-induced mouse hippocampal slices and the primary hippocampal neuron AD injury model,and its mechanism was swertisin increased the 2-AG signal to play neuroprotection and thus resistance to AD.