Metabolomics reveals hippocampal metabolic fluctuations of postoperative fatigue syndrome and anti-fatigue effect of Carthamus tinctorius L. extract in rat model

Postoperative fatigue syndrome (POFS) is a common clinical complication following almost every major abdominal surgery. There is not a full explanation of the etiology of POFS, especially its central mechanism. Carthamus tinctorius L. is a classic traditional Chinese medicine (TCM) which could exert ananti-fatigue effect on POFS. However, its mechanism is still lacking. Here, ultra-high performance liquid chromatography coupled with a quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOFMS) based metabonomic approach was used to characterize hippocampal metabolic fluctuations of POFS in a rat model induced by partial hepatectomy, and to evaluate the anti-fatigue effect of C. tinctorius L. extract (CTLE). With partial least-squares discriminant analysis for classification and selection of biomarkers, 15 hippocampal metabolites related to POFS were identified, primarily involving alanine, aspartate and glutamate metabolism, valine, leucine and isoleucine degradation, purine metabolism, phenylalanine metabolism, tryptophan metabolism, phospholipid metabolism and fatty acid metabolism. With these altered metabolic pathways as possible drug targets, we systematically analyzed the protective effect of CTLE, which showed that CTLE could provide an anti-fatigue effect on POFS through partially regulating the perturbed metabolic pathways. This study indicated that UHPLC-Q-TOFMS-based metabolomics provided a powerful tool to reveal hippocampal metabolic fluctuations of POFS and study the mechanism of TCM. Copyright (c) 2015 John Wiley & Sons, Ltd.