Beneficial effects of tempol, a membrane-permeable radical scavenger, in arodent model of splanchnic artery occlusion and reperfusion

The aim of the present study was to investigate the effects of tempol, a me mbrane-permeable radical scavenger, in rats subjected to splanchnic artery occlusion shock (SAG). Rats subjected to SAO developed a significant decrea se in mean arterial blood pressure, a significant increase in tissue myelop eroxidase activity, and a marked injury to the distal ileum. SAG shock resu lted in 100% mortality at 2 h after reperfusion. At 60 min after reperfusio n, a marked increase in the immunoreactivity to nitrotyrosine and to poly ( ADP-ribose) synthetase was observed in the necrotic ileum of rats with SAG. Staining of sections of the ileum obtained from SAG-shocked rats with anti -intercellular adhesion molecule (ICAM-1) and anti-P-selectin antibodies re sulted in diffuse staining. Tempol (30 mg/kg bolus injection 5 min prior to reperfusion, followed by an infusion of 30 mg/kg/h intravenously) attenuat ed 1) the infiltration of the reperfused intestine with neutrophils, 2) the lipid peroxidation, 3) the production of peroxynitrite, 4) the degree of P -selectin and ICAM-1 staining in tissue sections from SAG-shocked rats, 5) histological signs of bowel injury, and 6) mortality at 2 h after reperfusi on. Taken together, our results clearly demonstrate that the intracellular radical scavenger tempol reduces the intestinal injury of rats subjected SA G shock.