Combined With UPLC-Triple-TOF/MS-based Plasma Lipidomics And Molecular Pharmacology Reveals The Mechanism Of Schisandrin Against Alzheimer’s Disease

Objective:Alzheimer’s disease（AD）,a type of Neurodegeneration disease,is characterized by Aβdeposition and tangles of nerve fibers.In addition,inflammatory factors play an important role in the occurrence and development of AD.Studies have shown that changes in lipid metabolism are closely related to AD.At the same time,Liver X Receptor（LXR）is found.As a lipid-activated transcription factor in the nuclear receptor superfamily,LXR can play a role in connecting lipid metabolism and inflammation.Therefore,this study aims to explore the possible mechanism of an anti-AD drug（schisandrin,one of the main components of schisandra chinensis）to improve the pathology of AD in terms of the study on the pathway of lipid metabolism,inflammation and AD action.Methods:1.Morris water maze experiment was used to detect the spatial learning and memory ability of each group of rats,and to preliminarily test whether the AD rat model was successfully established and whether schisandrin improved the symptoms of AD rats.2.Western blot and immunohistochemistry were used to detect the expression and deposition of Aβin the brain of each group of rats,and the effects of schisandrin on the expression and deposition of Aβprotein were detected.3.Plasma lipidomics method based on ultra-high performance liquid chromatography-triple time-of-flight mass spectrometry（UPLC-Triple-TOF/MS）was used to investigate the changes of plasma lipids in rats.4.Molecular docking was used to verify the interaction between schisandrin and LXR receptor.5.The expressions of inflammatory cytokines IL-1β,i NOS,TNF-ɑand IL-6 in brain tissue and BV2microglia were detected by Western blot.6.Western blot,ELISA and q PCR were used to detect the expression of APOE and ABCA1,the target genes of LXR,in the rat brain and BV2 microglia.Results:1.Schisandrin can improve the learning ability and reduce the deposition of Aβin the brain of AD rats.2.The plasma lipidomics results showed that the plasma lipid metabolism of AD group rats was disorganized,a total of 56 lipid metabolites with significant changes and 11 related metabolic pathways were found.3.Molecular docking revealed the interaction between schisandrin and LXRβ.4.Western blot showed that inflammatory factors IL-1β,i NOS,TNF-ɑand IL-6 were highly expressed in the Model group,but decreased in the Sch group.5.The protein and m RNA levels of LXR target genes APOE and ABCA1 increased in Sch group,but there was no significant difference between Control group and Model group.6.CCK8assay confirmed that BV2 cells treated with 10μM Aβ_25-35 were the Model group,BV2 cells treated with 1μM schisandrin+10μM Aβ_25-35 were Sch group,and the Control group was not treated with any treatment.The BV2 cells treated with 10μM TO901317+10μM Aβ_25-35 were TO90 group.7.At the cell level,it was also found that the expression levels of LXR target genes APOE and ABCA1 protein and m RNA increased in Sch group,but there was no significant difference between Control group and Model group.Conclusions:Our study found:schisandrin can improve cognitive dysfunction and regulate plasma lipid metabolism disorder in AD rats.Based on the results of plasma lipidomics,we speculated that schisandrin might act on LXR,and the MOE docking results indicated that schisandrin interacts with LXRβ.In addition,schisandrin decreased the expression of inflammatory factors in the brain of AD rats and increased the protein and m RNA expressions of LXR target genes APOE and ABCA1in the brain of AD rats and BV2 microglia cells.In conclusion,all experimental results suggest that schisandrin improves the pathology of AD rats by activating LXR.