Nitric oxide decreases endothelial activation by rat experimental severe pancreatitis-associated ascitic fluids

To clarify the roles of nitric oxide (NO) in acute pancreatitis (AP), we ex amined the effects of NO on the endothelial activation induced by ascitic f luids from rats with experimental severe AP. Necrotizing hemorrhagic pancre atitis was induced in male Wistar rats with sodium taurocholate. Six hours later, peritoneal exudates were collected, centrifuged, and human umbilical vein endothelial cells were treated with the supernatants. Then (a) the mR NA level of endothelial-type NO synthase (ecNOS) was examined by reverse tr anscription-polymerase chain reaction; (b) effects of an NO donor, sodium n itroprusside (SNP) and an inhibitor of NOS, N-omega-nitro-L-arginine (L-NNA ) on the ascitic fluids-induced expression of intercellular adhesion molecu le-1, vascular cell adhesion molecule-1, and interleukin-8 were assessed by enzyme-linked immunoassay; (c) nuclear translocation of nuclear factor-kap pa B (NF-kappa B) was examined by electrophoretic mobility shift assay; and (d) effects of SNP and L-NNA on the adhesion of U937 cells to endothelial monolayer were assessed. The ecNOS mRNA level was decreased by the ascitic fluids; ascitic fluids-induced expression of adhesion molecules and interle ukin-8 as well as the nuclear translocation of NF-kappa B were attenuated b y SNP, whereas L-NNA augmented them; and the effects on the endothelial act ivation were paralleled by the altered adhesion of U937 cells to endotheliu m. The ability of NO to limit endothelial activation and inhibit leukocyte adhesion might contribute to its antiinflammatory properties in AP.