SULFASALAZINE OR ENTERAL DIETS CONTAINING FISH-OIL OR OLIGOSACCHARIDES ATTENUATE CHRONIC COLITIS IN RATS

Recent studies have suggested that n-3 fatty acids from fish oil (FO) as well as short-chain fatty acids may attenuate some of the gut injur y and inflammation-associated ulcerative colitic (UC). The objectives of this study were to (a) assess the antiinflammatory activity of sulf asalazine (SAZ), a drug known to be effective in the treatment of huma n UC in a model of chronic granulomatous colitis in rats and (b) deter mine whether enteral diets supplemented with either FO or two indigest ible oligosaccharides (fructooligosaccharide, FOS; xylooligosaccharide , XOS) could attenuate the inflammation observed in a model of chronic granulomatous colitis. In one series of experiments, female Lewis rat s were randomized into three groups consisting of a sham-operated cont rol group, a colitic group, and a colitic group in which rats were giv en oral sulfasalazine (SAZ) immediately after induction of colitis and continued for 3 weeks. Chronic granulomatous colitis with liver and s pleen inflammation was induced by subserosal (intramural) injection of purified peptidoglycan-polysaccharide (PG/PS) into the distal colon. Sham-operated rats were injected with human serum albumin. All rats re ceived standard lab chow. In a second series of experiments, female Le wis rats were randomized into six groups consisting of four colitic gr oups fed enteral diets, a colitic group fed chow, and a sham-operated group fed a control enteral diet. Enteral diets (300 kcal/kg/day) cont ained either FO, FOS/gum arabic, XOS/gum arabic, or no bioactive ingre dient (control diet). ALL rats were fed for 1 week before induction of colitis. Rats consumed the diets for 3 additional weeks before being killed. SAZ significantly attenuated the PG/PS-induced increases in my eloperoxidase (MPO) activity as well as significantly reduced the PG/P S-induced increases in liver and spleen weights. Control (enteral diet ) as well as the FO and XOS diets significantly attenuated the increas e in colon weight when compared with chow-fed rats. We also found that the FO and XOS diets significantly attenuated the PG/PS-induced incre ases in colonic MPO activity and colon weight. The FOS and XOS diets s ignificantly attenuated the PG/PS-induced increases in liver weights w hen compared with PG/PS + chow-fed animals. The antiinflammatory activ ity of these diets was confirmed by means of histological inspection s howing an inhibition of inflammation and maintenance of crypt cell int egrity. These results demonstrate that a complete enteral diet supplem ented with either FO, FOS, or XOS exhibited antiinflammatory activity that was similar in efficacy to the known antiinflammatory drug SAZ in this model of colitis.