A free radical scavenger, edaravone (MCI-186), diminishes intestinal neutrophil lipid peroxidation and bacterial translocation in a rat hemorrhagic shock model

Abstract

Objective: To investigate the effects of edaravone, a novel free radical scavenger, on bacterial translocation induced by hemorrhagic shock.

Design: Prospective, randomized, unblinded animal study.

Setting: Surgical research laboratories of Shiga University of Medical Science.

Subjects: Male specific-pathogen-free Sprague-Dawley rats.

Interventions: The rats were randomly divided into three groups: conventional saline treatment, edaravone treatment, and sham shock induction. The saline and edaravone groups were subjected to hemorrhagic shock (mean arterial pressure of 30 mm Hg, for 30 or 60 mins). Rats were killed 30 or 60 mins after shock induction. Mesenteric lymph nodes were cultured for determination of bacterial translocation. Systemic plasma silkworm larvae plasma test, which can detect peptidoglycan and beta-glucan, and endotoxin tests were performed. Immunohistochemistry for 4-hydroxy-2-nonenal (4-HNE) was used to assess lipid peroxidation after shock.

Measurements and main results: The incidence and magnitude of hemorrhagic-shock-induced bacterial translocation to mesenteric lymph nodes were reduced by edaravone. Hemorrhagic-shock-induced increase of plasma silkworm larvae plasma test was also reduced by edaravone. Immunohistochemistry for 4-HNE showed many 4-HNE-positive cells in the lamina propria of the ileum 60 mins after hemorrhagic shock. Double immunohistochemistry revealed that many of these 4-HNE-positive cells were also myeloperoxidase positive. Moreover, the percentage of double-labeled cells with 4-HNE and myeloperoxidase in myeloperoxidase-positive cells was significantly lower in the edaravone group than in the saline group.

Conclusions: The present findings suggest that lipid peroxidation of intestinal neutrophils is involved in bacterial translocation during hemorrhagic shock and that edaravone is potentially useful in diminishing bacterial translocation after hemorrhagic shock.