Chronic intrajejunal TNBS application in TNBS-sensitized rats: a new model of chronic inflammatory bowel diseases.

An enteritis, based on a delayed-type hypersensitivity reaction, was induced in TNBS (2,4,4-trinitrobenzenesulfonic acid) sensitized rats by intrajejunal challenge with TNBS. This treatment induced a chronic inflammation of the distal small intestine, characterized by gross hyperaemia and oedema, as assessed by a macroscopic score. Histologically, the inflammatory response included cell infiltration by lymphocytes and histiocytes, a transmural granulomatous inflammation with multinucleated cells and activated mesenteric lymph nodes. Drug treatment with sulfasalazine or 5-aminosalicylic acid improved enteritis score. The applicability and relevance of this new model is discussed in relation to drug development and basic research of inflammatory bowel diseases.