Amelioration of TNBS-induced colon inflammation in rats by phospholipase A2 inhibitor

The pathophysiology of inflammatory bowel disease (IBD) involves the production of diverse lipid mediators, namely eicosanoids, lysophospholipids, and platelet-activating factor, in which phospholipase A(2) (PLA(2)) is the key enzyme. Accordingly, it has been postulated that control of lipid mediator production by inhibition of PLA(2) would be useful for the treatment of IBD. This hypothesis was tested in the present study by examining the therapeutic effect of a novel extracellular PLA(2) inhibitor (ExPLI), composed of carboxymethylcellulose-linked phosphatidylethanolamine (CMPE), on trinitrobenzenesulfonic acid-induced colitis. Intraperitoneal administration of CMPE suppressed the colitis as measured by mortality rate, intestinal permeability, plasma PLA(2) activity, intestinal myeloperoxidase activity, and histological morphometry. Current therapeutic approaches for inflammatory conditions focus on the selective control of a lipid mediator(s) (e.g., prostaglandins or leukotrienes). The present study supports the concept that inclusive control of lipid mediator production by PLA(2) inhibition is a plausible approach to the treatment of colitis and introduces the ExPLIs as a prototype of a novel NSAID for the treatment of intestinal inflammation.