DHA and 20:4n-6 Oxygenated Metabolites in Rat Brains

Introduction In brain, docosahexaenoic (DHA) and arachidonic (ArA) acids are precursors of oxygenated lipid mediators involved in physiological and pathophysiological processes. Their characterization in free form and esterified in phospholipids, in rat brain homogenates, is crucial for better understanding their biological roles. Methods Free PUFA oxygenated derivatives were extracted from exanguinated rat brain homogenates by SPE and analyzed by LC-MS/MS. Results Several oxygenated metabolites derived from ArA and DHA are found in exsanguinated and non-exsanguinated brain, either free or esterified in phospholipids. Mono-hydroxylated metabolites were the main derivatives, however, measurable amounts of di-hydroxylated products such as 8(S),15(S)-diHETE and protectin DX/10(S),17(S)-diHDoHE, as well as prostanoids were detected. Metabolites formed via 12-LOX and 15-LOX, two enzymes notably found in blood cells, were decreased in exsanguinated brains. Conclusions These results obtained in normal rats deserve further research in pathophysiological conditions, especially in neurodegenerative diseases.