Developmental expression of STATs, nuclear factor-κB and inflammatory genes in the jejunum of piglets during weaning

The signal transducer and activator of transcription (STAT) proteins play essential roles in apoptosis, proliferation and survival. However, the role of STATs in intestinal inflammation during weaning is unclear. This study aimed to investigate developmental expression of STATs, nuclear factor-kappa B (NF-kappa B) and inflammatory genes in the jejunum of piglets during, weaning. Thirty-two piglets were weaned at 21 d and sacrificed at 0, 1, 7, or 14 d (n = 8) after weaning. Villus height and the villus height/crypt depth ratio were decreased, whereas crypt depth was increased in the jejunum at 7 and 14 d after weaning. In addition, the mRNA levels of interferon-gamma (IFN-gamma), inducible nitric oxide synthase (iNOS), IL-6, IL-8, IL-12 and IL-22 were increased in the jejunum at 7 and 14 d after weaning, whereas transforming growth factor-beta (TGF-beta), suppressor of cytokine signaling 3 (SCOS3) and arginase-1 was decreased. Neutrophil infiltration was increased in the mucosa of the jejunum after weaning. Moreover, phosphorylation of I kappa B-alpha, NF-kappa B, ART and STAT-3 was increased. However, the phosphorylation of STAT-1 (at 7 and 14 d) and STAT-6 (at 1 and 7 d) was suppressed in the jejunum after weaning. Treatment of porcine jejunal epithelial (IPEC-J2) cells with the STAT inhibitors fludarabine, niclosamide and teriflunomide, which inhibit the phosphorylation of STAT-1, STAT-3 and STAT-6, respectively, weakened the defense capacity of these cells against bacterial infection. In conclusion, weaning caused severe inflammation associated with activation of the NF-kappa B and STAT-3 pathways and suppression of STAT-1 and STAT-6 in the jejunum of piglets. (C) 2016 Elsevier B.V. All rights reserved.