Effect of rapamycin on hepatic metabolomics of non-alcoholic fatty liver rats based on non-targeted platform

Rapamycin (Rapa) is an inhibitor of mTOR complex, and its therapeutic effect on liver function was examined in non-alcoholic fatty liver disease (NAFLD) rats here. And the possible mechanism of Rapa in NAFLD was preliminarily elucidated based on the non-targeted metabolomics analysis. Adult male SD rats were fed with a high-fat and high-cholesterol diet (HFD) to establish NAFLD model. For Rapa group, 0.8 mg/(kg.d) Rapa was given to the HFD rats. Ultra-performance liquid chromatography and Q-Tof-mass spectrometry (UPLC and Q-TOF/MS) analysis were applied for the identification of metabolites in the serum of rats, which were annotated using Kyoto Encyclopedia of Genes and Genomes (KEGG). NAFLD rats presented with disturbed liver function, lipid metabolism and oxidative stress, but Rapa exerted a mitigating influence on the disorders. The metabolite profile data identified 579 metabolites that varied remarkably between the Rapa and HFD groups, with the main classes of amino acids and peptides, benzene, lipids and fatty acids. The differential metabolites were mainly involved in biosynthesis of cofactors, bile secretion, and glycerophospholipid metabolism were mainly enriched. In conclusion, Rapa has a potential protective effect against HFD-induced NAFLD, its hepatoprotective effect may achieved through mediating bile secretion and glycerophospholipid metabolism.