Developmental changes of TGF-?1 and Smads signaling pathway in intestinal adaption of weaned pigs.

ABSTRACT: Weaning stress caused marked changes in intestinal structure and function. Transforming growth factor-?1 (TGF-?1) and canonical Smads signaling pathway are suspected to play an important regulatory role in post-weaning adaptation of the small intestine. In the present study, the intestinal morphology and permeability, developmental expressions of tight junction proteins and TGF-?1 in the intestine of piglets during the 2 weeks after weaning were assessed. The expressions of TGF-? receptor I/II (T?RI, T?RII), smad2/3, smad4 and smad7 were determined to investigate whether canonical smads signaling pathways were involved in early weaning adaption process. The results showed that a shorter villus and deeper crypt were observed on d 3 and d 7 postweaning and intestinal morphology recovered to preweaning values on d 14 postweaning. Early weaning increased (P<0.05) plasma level of diamine oxidase (DAO) and decreased DAO activities (P<0.05) in intestinal mucosa on d 3 and d 7 post-weaning. Compared with the pre-weaning stage (d 0), tight junction proteins level of occludin and claudin-1 were reduced (P<0.05) on d 3, 7 and 14 post-weaning, and ZO-1 protein was reduced (P<0.05) on d 3 and d 7 post-weaning. An increase (P<0.05) of TGF-?1 in intestinal mucosa was observed on d 3 and d 7 and then level down on d 14 post-weaning. Although there was an increase (P<0.05) of T?R II protein expression in the intestinal mucosa on d3 and d 7, no significant increase of mRNA of T?RI, T?RII, smad2/3, smad4 and smad7 was observed during postweaning. The results indicated that TGF-?1 was associated with the restoration of intestinal morphology and barrier function following weaning stress. The increased intestinal endogenous TGF-?1 didn't activate the canonical Smads signaling pathway.

SUBMITTER: Xiao K 

PROVIDER: S-EPMC4149345 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature