Serum metabolite profiles of postoperative fatigue syndrome in rat following partial hepatectomy

Postoperative fatigue syndrome is a general complication after surgery. However, there is no ''gold standard'' for fatigue assessment due to the lack of objective biomarkers. In this study, a rodent model of postoperative fatigue syndrome based on partial hepatectomy was firstly established and serum metabonomic method based on ultra-high performance liquid chromatography coupled with Q-TOF mass spectrometry was applied. Partial least-squares discriminant analysis was used to identify the differential metabolites in 70% partial hepatectomy rats relative to sham rats and 30% partial hepatectomy rats, which showed 70% partial hepatectomy group was significantly distinguishable from 30% partial hepatectomy group and sham group. Eighteen serum metabolites responsible for the discrimination were identified. The levels of hypoxanthine, kynurenine, tryptophan, uric acid, phenylalanine, palmitic acid, arachidonic acid and oleic acid showed progressive elevation from sham group to 30% partial hepatectomy group to 70% partial hepatectomy group, and levels of valine, tyrosine, isoleucine, linoleyl carnitine, palmitoylcarnitine, lysophosphatidylcholine (16:0), lysophosphatidylcholine (20:3), citric acid, succinic acid and hippuric acid showed progressive declining trend from sham group to 30% partial hepatectomy group to 70% partial hepatectomy group. These potential biomarkers help to understand of etiology, pathophysiology and treatment of postoperative fatigue syndrome.