Characterization of changes in plasma and tissue oxylipin levels in LPS and CLP induced murine sepsis

The present study aimed to comprehensively investigate the changes in oxylipins during murine sepsis induced by lipopolysaccharide (LPS) or cecal ligation and puncture (CLP). Twenty-four hours after induction of sepsis in male C57BL/6 mice by LPS or CLP, plasma and liver, lung, kidney and heart tissues were sampled. Oxylipin levels in plasma and tissue were quantified by means of LC-MS. Moreover, clinical chemistry parameters were determined in plasma and interleukin levels (MCP-1 and IL-6) were determined in kidney and liver. Elevation of liver function plasma parameters at 24 h revealed that both models were successful in the induction of sepsis. LPS induced sepsis resulted in a dramatic increase of plasma PGE(2) (2,100 % change in comparison to control) and other cyclooxygenase metabolites, whereas this effect was less pronounced in CLP induced sepsis (97 % increase of PGE(2)). Plasma epoxy-fatty acids (FAs) and hydroxy-FAs and most of the dihydroxy-FAs were elevated in both models of sepsis. Changes of tissue oxylipin concentrations were organ dependent. Only few changes were detected in the lung and liver tissue, epoxy-FAs were elevated in the kidney. In the heart tissue a trend towards lower levels of hydroxy-FAs and epoxy-FAs was observed. Both murine models of sepsis are characterized by changes of oxylipins formed in all branches of the arachidonic acid (AA) cascade. The more pronounced effects in the LPS model make this model more suitable for the investigation of the AA cascade and its pharmacological modulation in sepsis.