Nitric Oxide and Carbon Monoxide mediate the anti-inflammatory effects of Remote Ischemic Preconditioning (RIPC) (94.12)

Abstract

Abstract Remote ischemic preconditioning(RIPC) consists of short periods of ischemia followed by reperfusion, which induces protective anti-inflammatory effect on distance organs. Studies have shown that inflammatory parameters such as leukocyte migration are significantly reduced in pre-conditioned animals.However, the mechanism involved in this effect is not yet well established. This study evaluated if NO and CO is mediating the anti-inflammatory activity of RIPC.RIPC model is based on turnstile in right leg of a mouse for 10 minutes followed by 30 of reperfusion. Participation of NO and CO was investigated using inhibitors of iNOS (1400W; 3mg/kg or Aminoguanide; 50mg/kg) and HO-1 (ZnPPIX;10mg/kg) as pre-treatment 30 minutes before RIPC. Afterwards, inflammatory reaction was induced by intraperitoneal administration of Carragenin(500µg/cav).Four hours after the peritoneal cavities were washed with saline and number of migrated leukocytes was evaluated. Chemotaxis ability of neutrophils obtained from mice under RIPC treated or not with the inhibitors was analyzed in Boyden Chamber. Expression of CXCR2 and GRK2 in neutrophils was determined by flow cytometry and immunofluorescence, respectively.CO and NO inhibitors prevented the inhibitory effect of RIPC upon Cg-induced neutrophil migration into peritoneal cavity of animals, as well as, upon KC induced neutrophils chemotaxis in Boyden Chamber. The reduction of neutrophil chemotaxis by RICP correlated with CXCR2 internalization and increase of GRK2 expression in the neutrophils.CO and NO production prevented these effects of RICP.Thus,inhibitors of HO-1/CO and NOSi/NO pathways seem to mediate the anti-inflammatory effect of RICP.