Dietary monounsaturated n-3 and n-6 long-chain polyunsaturated fatty acidsaffect cellular antioxidant defense system in rats with experimental ulcerative colitis induced by trinitrobenzene sulfonic acid

The intrarectal administration of trinitrobenzene sulfonic acid in rats ind uces ulcerative colitis, which results in histological alterations of colon ic mucosa, severe modification of the cellular antioxidant defense system, and enhanced production of inflammatory cicosanoids. This study evaluated t he influence of different dietary fatty adds, ie, monounsaturated, n-3, and n-3 + n-6 polyunsaturated fatty acids, on the recovery of the colonic muco sa histological pattern, the cellular antioxidant defense system of colon, and PGE(2) and LTB4 colonic mucosa contents in a model of ulcerative coliti s induced by intrarectal administration of trinitrobenzene sulfonic acid. A dministration of dietary n-3 polyunsaturated fatty acids led to a minimum s tenosis score, a higher histological recovery, lower colon alkaline phospha tase and gamma-glutamyltranspeptidase activities, and lower mucosal levels of PGE(2) and LTB4 compared with the other two experimental groups. However , glutathione transferase, glutathione reductase, glutathione peroxidase, a nd catalase activities were lower in the group treated with n-3 polyunsatur ated fatty acids than in the groups fed with either the monounsaturated or the n-6 + n-3 polyunsaturated enriched diet. We conclude that n-3 polyunsat urated fatty acids can be administered to prevent inflammation in ulcerativ e colitis, but they cause a decrease in the colonic antioxidant defense sys tem, promoting oxidative injury at the site of inflammation.