Prostacyclin synthase deficiency exacerbates systemic inflammatory responses in lipopolysaccharide-induced septic shock in mice

Sepsis is a systemic inflammatory disorder characterized by life-threateningorgan dysfunction resulting from a dysregulated host response to infection. Prostacyclin (PGI2) is a bioactive lipid produced by PGI synthase (PGIS) and is known to play important roles in inflammatory reactions as well as cardiovascular regulation. However, little is known about the roles of PGIS and PGI2 in systemic inflammatory responses such as septic shock. Systemic inflammation was induced by intraperitoneal injection of 5 mg/kg lipopolysaccharide (LPS) in wild type (WT) or PGIS knockout (KO) mice. Selexipag, a selective PGI2 receptor (IP) agonist, was administered 2 h before LPS injection and again given every 12 h for 3 days. Intraperitoneal injection of LPS induced diarrhea, shivering and hypothermia. These symptoms were more severe in PGIS KO mice than in WT micqe. The expression of Tnf and Il6 genes was notably increased in PGIS KO mice. In contrast, over 95