Protection by rebamipide against acetic acid-induced colitis in rats: relationship with its antioxidative activity

The aim of this study was to examine the efficacy of rebamipide on acetic acid-induced colitis in rats. Colitis was induced in male Wistar/ST strain rats by intracolonic injection of 2 ml of 5% acetic acid. After 24 hr, lesion score, myeloperoxidase (MPO) activity, thiobarbituric acid-reactive substances (TBARS), and antioxidants were measured. Rebamipide was administered orally to the rats twice, once immediately and once 8 hr after the induction of the colitis at doses of 7.5, 15, and 30 mg/kg. To evaluate the pathogenesis of neutrophils in this colitis model, neutrophil-depleted rats were also investigated. Increases of TBARS and MPO activity and decreases of total glutathione, superoxide dismutase (SOD) activity, and alpha-tocopherol were observed in this model. Rebamipide at 30 mg/kg decreased the lesion score significantly, which was associated with the reduction of colonic TBARS. The decreases of total glutathione, SOD activity, and alpha-tocopherol were also inhibited significantly by rebamipide. The preventive effect of rebamipide in this colitis model may be attributed to its inhibition of reactive oxygen species production.