Metabolic profiling of liver tissues in mice after instillation of fine particulate matter

Human exposure to fine particulate matter (PM_2.5) in various environment could lead to a number of adverse health effects. Little is known about the toxic mechanism and the further response caused by PM_2.5 exposure. In this study, a metabolomics approach using gas chromatography-mass spectrometry (GC-MS) was adopted to evaluate the liver toxicity induced by different gradient concentrations of PM_2.5. A multivariate statistical analysis had shown, a total of 12 endogenous metabolites including amino acids and organic acids were identified as potential biomarkers of PM_2.5 and most of them were down-regulated. By analyzing the metabolic pathways using the identified biomarkers, the significantly interfered metabolic pathways when mice were exposed to PM_2.5 were found as: glycine, serine and threonine metabolism, aminoacyl-tRNA biosynthesis, cysteine and methionine metabolism, alanine, aspartate and glutamate metabolism, methane metabolism, linoleic acid metabolism and valine, and leucine and isoleucine biosynthesis, all of which were closely related to liver metabolism. The findings of this study reveal detailed toxic metabolic effects of PM_2.5 in liver tissues, provide ways for assessing the health risk of PM_2.5 at molecular level, and further offer insights on the potential mechanism of its toxicity.