Metabolomic and Lipidomic Analysis of Serum from Mice Exposed to an Internal Emitter, Cesium-137, Using a Shotgun LC-MSE Approach

In this study ultra performance liquid chromatography (UPLC) coupled to time-of-flight mass spectrometry in the MSE mode was used for rapid and comprehensive analysis of metabolites in the serum of mice exposed to internal exposure by Cesium-137 (Cs-137). The effects of exposure to Cs-137 were studied at several time points after injection of (CsCl)-Cs-137 in mice. Over 1800 spectral features were detected in the serum of mice in positive and negative electrospray ionization modes combined. Detailed statistical analysis revealed that several metabolites associated with amino acid metabolism, fatty acid metabolism, and the TCA cycle were significantly perturbed in the serum of Cs-137-exposed mice compared with that of control mice. While metabolites associated with the TCA cycle and glycolysis increased in their serum abundances, fatty acids such as linoleic acid and palmitic acid were detected at lower levels in serum after Cs-137 exposure. Furthermore, phosphatidylcholines (PCs) were among the most perturbed ions in the serum of Cs-137-exposed mice. This is the first study on the effects of exposure by an internal emitter in serum using a UPLC-MSE approach. The results have put forth a panel of metabolites, which may serve as potential serum markers to Cs-137 exposure.