Edaravone, a newly developed radical scavenger, protects against ischemia-reperfusion injury of the small intestine in rats

Although edaravone (3-methyl-1-phenyl-pyrazolin-5-one), a newly developed radical scavenging agent, has been widely used for protection against ischemia-reperfusion (I-R) injury in patients with cerebral infarction, its effects on gastrointestinal I-R injury have not been evaluated. In the present study, we examined the effects of edaravone on experimental intestinal I-R damage in rats. In male Wistar rats with and without edaravone treatment, intestinal damage was induced by clamping the superior mesenteric artery for 30 min, followed by reperfusion. Edaravone was administered via intravenous infusion at 5 min before reperfusion was achieved by removal of the clamp. The rats were sacrificed after 60 min of reperfusion. Luminal protein and hemoglobin concentrations were measured as an index of mucosal injury and histological examination of hematoxylin and eosin-stained sections was performed. Thiobarbituric acid (TBA)-reactive substances and tissue-associated myeloperoxidase (MPO) activity were measured in the mucosa as indicators of lipid peroxidation and neutrophil infiltration, respectively. The mucosal concentration of cytokine-induced neutrophil chemoattractant (CINC)-1 (a member of the IL-8 family) was determined by enzyme-linked immunosorbent assay (ELISA). Additionally, CINC-1 messenger RNA (mRNA) was measured by the reverse-transcription polymerase chain reaction (RTPCR). As a result, the levels of luminal protein and hemoglobin, TBA-reactive substances, and MPO activity were all increased significantly by I-R injury, and these increases were significantly inhibited by treatment with edaravone. Multiple erosions and bleeding were observed macroscopically after the small intestine was exposed to I-R injury, and these changes were inhibited by administration of edaravone. Microscopic I-R damage was also reduced by treatment with edaravone. CINC-1 protein and CINC-1 mRNA were both increased by I-R injury, while edaravone markedly reduced the levels of both protein and mRNA. In summary, these results suggest that edaravone can protect the small intestine against I-R injury by scavenging oxygen-derived free radicals.