Ameliorative effects of riboflavin on acetic acid-induced colonic injury in rats.
Clin Exp Pharmacol Physiol. 2017 Nov 22. Epub 2017 Nov 22. PMID: 29164668
Riboflavin (RF) has been found to be a promising antioxidant and/or anti-inflammatory agent in several studies. However, the effect of RF against acetic acid (AA)-induced colonic injury is currently unknown. This study aimed to investigate the potential antioxidant and protective effects of RF in a rat model of ulcerative colitis. Starting immediately after the colitis induction (AA+RF group) or 1 week before the colitis induction (RF+AA+RF group), the rats were treated with RF (25 mg/kg/d;p.o.) for 3 days. The control and AA groups received saline (1 ml;p.o.) whereas AA+SS group (positive control) received sulfasalazine (100 mg/kg/d;p.o.) for 3 days. Colonic samples were taken for the biochemical and histological assessments on the 3rd day. High damage scores, elevated tissue wet weight index (WI), tissue myeloperoxidase (MPO) activity, 8-hydroxy-2' -deoxyguanosine levels and chemiluminescence values, and a pronounced decrease in antioxidant glutathione (GSH) levels of the AA group were all reversed by RF pretreatment (RF+AA+RF group) and SS treatment (AA+SS group) (p<0.05-0.001). Tissue WI, MPO activity and GSH levels were not statistically changed in the AA+RF group. Western blot analysis revealed that the decreased protein expressions of tissue collagen (COL) 1A1, COL3A1 and transforming growth factor-β1 in the AA group were elevated in all the treatment groups (p<0.05-0.001). In conclusion, RF exerts both the antioxidant and anti-inflammatory effects against AA-induced colonic inflammation by suppressing neutrophil accumulation, inhibiting reactive oxidant generation, preserving endogenous glutathione, improving oxidative DNA damage and regulating inflammatory mediators, suggesting a future potential role in the treatment and prevention of ulcerative colitis. This article is protected by copyright. All rights reserved.