Quantitative profiling of phosphatidylcholine and phosphatidylethanolamine in a steatosis/fibrosis model of rat liver by nanoflow liquid chromatography/tandem mass spectrometry

Quantitative analysis of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) was carried out using a steatosis/fibrosis model of rat livers, which were induced by a chronic administration of carbon tetrachloride (CCl4). Intact phospholipid mixtures from each liver sample (from rats fed with 0.5 mL CCl4/kg three times a week for 30, 60, and 90 days) were analyzed by nanoflow liquid chromatography–electrospray ionization tandem mass spectrometry (nLC/ESI/MS/MS), and identifications of 37 PC and 19 PE species were made by collision-induced dissociation. The quantitative analysis utilized a multiple standard addition method with an internal standard, and the relationship between the MS peak intensities of different PC species and their carbon chain length was included for calibration. It was found that the total amount of PC and PE species decreased significantly with administration of CCl4. While concentrations of most PC and PE species decreased to a great extent, three PEs and seven PCs were up-regulated more than twofold.