Soy-Derived Di- and Tripeptides Alleviate Colon and Ileum Inflammation in Pigs with Dextran Sodium Sulfate-Induced Colitis

We evaluated the antiinflammatory activity of soy-derived di- and tripeptides in a dextran sodium sulfate (DSS)-induced pig model of intestinal inflammation. In the DSS-positive control (POS) and DSS-positive with soy peptide treatment (SOY) groups (n = 6/group), DSS was administered to piglets via i.g. catheter for 5 d, followed by a 5-d administration of saline or soy-derived peptides, respectively. A negative control (NEG) group received saline in lieu of the DSS and soy peptides. The severity of inflammation was assessed by clinical signs, morphological and histological measurements, gut permeability, and neutrophil infiltration. Local production of TNF and IL6 were measured by ELISA, colonic and ileal inflammatory gene expression were assessed by real-time RT-PCR, and CD4(+)CD25(+) lymphocyte populations were analyzed by flow cytometry. Crypt elongation and muscle thickness, D-mannitol gut permeation, colonic expression of the inflammatory mediators IFNG, IL1B, TNF, RORC, and IL17A as well as the FOXP3 T-regulatory transcription factor, and myeloperoxidase activity were lower (P < 0.05) in the SOY pigs than in POS pigs. Messenger RNA levels of ileal IFNG, TNF, IL12B, and IL17A were lower (P < 0.05) and FOXP3 expression was greater (P < 0.05) in SOY piglets than in the POS group. In the mesenteric lymph nodes, CD4(+)CD25(+) T cells were higher (P < 0.05) in both the POS and SOY groups than in NEG controls. Soy-derived peptides exert antiinflammatory activity in vivo, suggesting their usefulness for the treatment of inflammatory disorders. J. Nutr. 142: 363-368, 2012.