Ketogenic diet induces systemic and tissue-specific metabolic remodeling in mice: an untargeted GC-MS metabolomics study

Objective To systematically characterize the effects of a ketogenic diet (KD) on the serum and multi-tissue metabolomes of mice using untargeted gas chromatography-mass spectrometry (GC-MS), with particular emphasis on systemic and tissue-specific metabolic remodeling. Methods 30 specific-pathogen-free male C57BL/6J mice aged 5–6 weeks were randomly assigned to a ketogenic-diet group (KD, n = 15) or a standard-diet group (Std, n = 15) and maintained on the assigned diets for 28 days. Serum, heart, liver, spleen, lung, kidney, small intestine, hippocampus, skeletal muscle, and brown adipose tissue were collected for untargeted GC-MS metabolomic profiling. Principal component analysis, partial least squares discriminant analysis, differential-metabolite screening, and Kyoto Encyclopedia of Genes and Genomes pathway enrichment and topology analyses were performed. Results The metabolic profiles of serum and multiple tissues showed clear separation between the KD and Std groups. A total of 52 candidate differential metabolites identified using a nominal P < 0.05 threshold were identified, including 3-hydroxybutyrate, O-phosphoethanolamine, amino acids, fatty acids, and intermediates of the tricarboxylic acid cycle. Enrichment analysis indicated that KD primarily affected glycerolipid and glycerophospholipid metabolism, sphingolipid metabolism, fatty acid metabolism, the tricarboxylic acid cycle, pyruvate metabolism, amino acid metabolism, glutathione metabolism, and pyrimidine metabolism. The magnitude and pattern of these changes differed substantially among tissues. Conclusion A 28-day KD induced broad systemic metabolic reprogramming in otherwise healthy mice. The response was centered on ketone-body metabolism, lipid oxidation, tricarboxylic acid cycle activity, and amino acid metabolism and was strongly tissue dependent. These findings provide a metabolomic basis for further investigation of the mechanisms and potential therapeutic applications of KD, including its possible role in neurological injury.