Effects of the ambient fine particulate matter (PM2.5) exposure on urinary metabolic profiles in rats using UPLC-Q-TOF-MS

In order to study the damage of ambient fine particulate matter (PM2.5) to organism in the environment, the method of urinary metabolomics was used to detect the potential endogenous metabolites and their related metabolic pathways to clarify the toxicity mechanisms. Particles of PM2.5 collected from the fibrous membrane were extracted ultrasonically and dissolved in physiological saline to prepare PM2.5 suspension. The solution of saline and fine particular matter was injected into the trachea of rats respectively. The rats were injected two times a week for four weeks. Samples of 24-h urine were collected at the 14th day after the end of exposure, and the ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was used for the metabolomics detection. Principal component analysis (PCA) was used to investigate the global metabolomic alterations and a clear separation in the scatter diagram were observed. 17 potential endogenous metablites were identified from urinary samples in rats by UPLC-Q-TOF-MS. The primary metabolism pathways involved pentose and glucuronate interconversions, starch and sucrose metabolism, tryptophan metabolism, tyrosine metabolism, phenylalanine metabolism, purine metabolism, acetaminophen metabolism pathway, retinol metabolism and valproic acid metabolism pathway. The results are helpful to understand the toxicological mechanisms of PM2.5 and screened out potential biomarkers of rats which exposure to PM2.5.