Untargeted metabolite profiling reveals metabolic disorders in livers of rats with mepiquat exposure

Mepiquat is a contaminant produced in thermal-processed food. It can induce spleen and liver injury. However, the mechanism that mepiquat induced hepatotoxicity remains unclear. In this study, a ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS)-based metabolomic analysis of livers in rats was performed to explore metabolic alterations. Our results demonstrated that there were 36 differential metabolites. Eleven major disordered metabolic pathways were found. Network analysis of differential metabolites and metabolic pathways indicated that glutamic acid was a possible key upregulated metabolite. It participated in nine metabolic networks. Glutathione and l-proline may be key downregulated metabolites. They were involved in eight and seven metabolic pathways, respectively. Compared with the control group, serum concentrations of alanine aminotransferase, aspartate aminotransferase, and total bile acid in high dosage group increased significantly. In addition, histopathological analysis showed liver injury in rats with mepiquat exposure. These data were consistent with results of metabolomics. Our results offered new insights for molecular mechanism of liver toxicity induced by mepiquat. PRACTICAL APPLICATION: Mepiquat is a contaminant formed in thermal-processed food. It can induce spleen and liver injury. Our results offered new insights for molecular mechanism of liver toxicity induced by mepiquat. It will provide important information for official limits of mepiquat in foods.