A total of 50 μL of serum and approximately 10mg of hippocampal tissues (wet weight) were used for sample preparation following previously reported methods (51 (link), 52 (link)). Samples were analyzed using an Agilent 6550 iFunnel Q-TOF LC/MS system (Agilent) with an Acquity UPLC HSS T3 column (53 (link)). Raw data were converted to mzXML format by ProteoWizard 3.0 package and uploaded to XCMS online (54 (link)). Metabolites were identified against METLIN (55 (link)) and Human Metabolome Database (56 (link)). Multivariate analysis was performed with SIMCA 13.0 (Umetrics). VIP scores were assessed. Discriminated metabolites were defined with a VIP > 1.0 by partial least squares-discriminant analysis (PLS-DA), P < 0.01, FDR-adjusted P < 0.05. Pathway enrichment analysis were analyzed using Metaboanalyst 4.0 (57 (link)).
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