Short-chain fatty acids profiling in biological samples from a mouse model of Sjögren’s syndrome based on derivatized LC-MS/MS assay

An analytical platform is required to characterize the short-chain fatty acids (SCFAs) in a mouse model of pathological immune conditions. Therefore, liquid chromatography tandem mass spectrometry combined with 2-picolylamine derivatization and a comprehensive study of SCFAs distribution based on serum, saliva, feces, liver, and brain from a mouse model of Sjögren's syndrome (SS) is performed. The design of experiments is used to achieve efficient 2-picolylamine derivatization, and optimize the reaction conditions. Twelve SCFAs are derivatized, and separated on a reversed-phase C18 column. All SCFAs show high linearity (r2 > 0.995) and intra/inter-day accuracy values from 71.6% to 115.6% (precision < 13.7%). This method was used to determine SCFAs concentrations in the serum, saliva, feces, liver, and brain of an SS model mice, and isobutyric acid, valeric acid, isovaleric acid, and 2-methylbutyric acid in liver from SS were significantly different compared with control group. Moreover, the preliminary evaluation of propionic acid, butyric acid, isobutyric acid, valeric acid, and isovaleric acid in saliva is conducted based on the respective SS stages and are correlated with these histological scores. This analytical platform for the widely SCFAs profiling in several tissues can be a clue for studying unclear immune pathophysiology.