title: Developmental changes of TGF-β1 and Smads signaling pathway in intestinal adaption of weaned pigs.
abstract: Weaning stress caused marked changes in intestinal structure and function. Transforming growth factor-β1 (TGF-β1) 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-β1 in the intestine of piglets during the 2 weeks after weaning were assessed. The expressions of TGF-β receptor I/II (TβRI, TβRII), 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-β1 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 TβR II protein expression in the intestinal mucosa on d3 and d 7, no significant increase of mRNA of TβRI, TβRII, smad2/3, smad4 and smad7 was observed during postweaning. The results indicated that TGF-β1 was associated with the restoration of intestinal morphology and barrier function following weaning stress. The increased intestinal endogenous TGF-β1 didn't activate the canonical Smads signaling pathway.
authors.affiliation: Animal Science College, Zhejiang University, The Key Laboratory of Molecular Animal Nutrition, Ministry of Education, Hangzhou, China.
authors.forename: Kan
authors.initials: K
authors.lastname: Xiao
authors.affiliation: Animal Science College, Zhejiang University, The Key Laboratory of Molecular Animal Nutrition, Ministry of Education, Hangzhou, China.
authors.forename: Ze-He
authors.initials: ZH
authors.lastname: Song
authors.affiliation: Animal Science College, Zhejiang University, The Key Laboratory of Molecular Animal Nutrition, Ministry of Education, Hangzhou, China.
authors.forename: Le-Fei
authors.initials: LF
authors.lastname: Jiao
authors.affiliation: Animal Science College, Zhejiang University, The Key Laboratory of Molecular Animal Nutrition, Ministry of Education, Hangzhou, China.
authors.forename: Ya-Lu
authors.initials: YL
authors.lastname: Ke
authors.affiliation: Animal Science College, Zhejiang University, The Key Laboratory of Molecular Animal Nutrition, Ministry of Education, Hangzhou, China.
authors.forename: Cai-Hong
authors.initials: CH
authors.lastname: Hu
mesh_terms: D000818:Animals; D007422:Intestines / Q000033:anatomy & histology* / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D015398:Signal Transduction; D051785:Smad Proteins / Q000235:genetics / Q000378:metabolism*; D013552:Swine / Q000502:physiology*; D053773:Transforming Growth Factor beta1 / Q000032:analysis / Q000378:metabolism*; D014886:Weaning
chemical_list: D012333:RNA, Messenger; D051785:Smad Proteins; D053773:Transforming Growth Factor beta1