Search

Evidence from several epidemiological and experimental studies points to a beneficial role of dietary polyphenols in inflammatory bowel disease. In this study, we investigate the protective effect of dietary supplementation with various amounts of a polyphenol-rich grape pomace extract (GPE) on the development of dextran sulfate sodium (DSS)-induced colitis in rats. Rats were fed 21 days on a semisynthetic diet enriched with GPE (0.1%, 0.5%, and 1%), and acute colitis was induced by DSS (40 g/L in the drinking water) administration during the last 7 days. The low GPE content in the diet (0.1%) attenuated clinical signs and colon shortening and limited DSS-induced histological lesions. GPE 0.1% also attenuated the DSS-induced increase in myeloperoxidase activity and improved superoxide dismutase activity. Higher amounts of GPE in the diet induced only weak and nonsignificant protective effects. These results suggest that consumption of a low amount of polyphenol-rich GPE helps protect against colitis development.

Supporting information may be found in the online version of this articleThis work was funded by 3inature Biosphère. The authors thank the GenoToul Anexplo-Phenotypage platform (IFR150, Toulouse,France) for assaying colonic cytokines using the Luminex technology,and Sophie Garcin for her technical assistance in handling rats; BACKGROUND: Several studies have reported that polyphenols may exert beneficial effects on inflammatory bowel disease. This study aimed to evaluate the effects of a preventive consumption of polyphenol-rich red grape pomace extracts (GPEs) on dextran sodium sulfate (DSS)-induced colitis in rats. Rats were fed for 21 days with a semi-synthetic diet enriched with a GPE (Alicante-S, Alicante-P and Pinot-S) and colitis was induced by DSS administration in drinking water (40 g L-1 ) during the last 7 days of experimentation. RESULTS: GPEs attenuated clinical signs and colon shortening and Alicante GPEs limited histological lesions induced by DSS. GPEs curbed the increase in myeloperoxidase activity and modulated antioxidant enzyme activities. Moreover, GPEs prevented the DSS-induced increase of pro-inflammatory cytokine levels and the upregulation of various genes implicated in colitis such as intercellular adhesion molecule-1 (ICAM-1) and matrix metalloproteinase 9 (MMP-9). CONCLUSION: These results suggest that polyphenol-rich red GPEs could provide prevention against colon inflammation

International audience; Dextran sodium sulphate (DSS)-induced colitis is a widely used model for inflammatory bowel disease. However, various factors including nutrition may affect the development of this colitis. This study aimed to compare and characterize the impact of purified and non-purified basal diets on the development of DSS-induced colitis in the rat. Wistar rats were fed a non-purified or a semi-synthetic purified diet for 21 days. Colitis was then induced in half of the rats by administration of DSS in drinking water (4 % w/v) during the last 7 days of experimentation. At the end of the experimental period, colon sections were taken for histopathological examination, determination of various markers of inflammation (myeloperoxidase: MPO, cytokines) and oxidative stress (superoxide dismutase: SOD, catalase: CAT, glutathione peroxidase: GPx and glutathione reductase: GRed activities), and evaluation of the expression of various genes implicated in this disorder. DSS ingestion induced a more marked colitis in animals receiving the purified diet, as reflected by higher histological score and increased MPO activity. A significant decrease in SOD and CAT activities was also observed in rats fed the purified diet. Also, in these animals, administration of DSS induced a significant increase in interleukin (IL)-1α, IL-1β and IL-6. In addition, various genes implicated in inflammation were over-expressed after ingestion of DSS by rats fed the purified diet. These results show that a purified diet promotes the onset of a more severe induced colitis than a non-purified one, highlighting the influence of basal diet in colitis development.