N-3 fatty acid-rich diet prevents early response of interleukin-6 elevation in trinitrobenzene sulfonic acid-induced enteritis

Dietary fat is an important factor involved in the pathogenesis of inflammatory bowel disease (IBD). It remains unclear how n-3 and n-6 fatty acids modulate intestinal inflammation. In this study, we investigated the effects of n-3 and n-6 fatty acid-rich diets on trinitrobenzene sulfonic acid (TNBS)-induced enteritis. The rats were fed an n-3 or n-6 rich-diet for 12 days, and then starved for the following 2 days. An intraileal injection of TNBS was administered, and TNBS-enteritis subsequently developed. Macroscopic and histological examination was performed after 24 h. Serum cytokine levels were determined by ELISA. The n-6 fatty acid-rich diet markedly enhanced mucosal damage as compared to the n-3 fatty acid-rich diet. The damage score was significantly higher in the n-6 fatty acid-rich diet group (P<0.05). Histological changes in the mucosa were more severe in the n-6 fatty acid-rich diet group than in the n-3 fatty acid-rich group. Serum IL-6 levels were significantly higher in the n-6 fatty acid-rich diet group than in the n-3 fatty acid-rich group (P<0.05). On the other hand, there were no differences in serum TNF-α levels. The n-3 fatty acid-rich diet effectively reduced early mucosal inflammation in TNBS enteritis. The effects of the n-3 fatty acids were associated with blockage of mucosal IL-6 secretion. Our data suggest that n-3 fatty acid-rich diet may be applicable for enteral nutrition in the treatment of IBD patients.