Whey protein concentrate enhances intestinal integrity and influences transforming growth factor-beta 1 and mitogen-activated protein kinase signalling pathways in piglets after lipopolysaccharide challenge

卷:115

Xiao, Kan ; Jiao, Lefei ; Cao, Shuting ; Song, Zehe ; Hu, Caihong ; Han, Xinyan

Zhejiang Univ

关键词: Whey protein concentrate;    Intestinal integrity;    Transforming growth factor-beta 1;    Mitogen-activated protein kinase;    Piglets;   

DOI  :  10.1017/S0007114515005085

学科分类：食品科学和技术

【 摘 要 】

Whey protein concentrate (WPC) has been reported to have protective effects on the intestinal barrier. However, the molecular mechanisms involved are not fully elucidated. Transforming growth factor-beta 1 (TGF-beta 1) is an important component in the WPC, but whether TGF-beta 1 plays a role in these processes is not clear. The aim of this study was to investigate the protective effects of WPC on the intestinal epithelial barrier as well as whether TGF-beta 1 is involved in these protection processes in a piglet model after lipopolysaccharide (LPS) challenge. In total, eighteen weanling pigs were randomly allocated to one of the following three treatment groups: (1) non-challenged control and control diet; (2) LPS-challenged control and control diet; (3) LPS + 5 % WPC diet. After 19 d of feeding with control or 5 % WPC diets, pigs were injected with LPS or saline. At 4 h after injection, pigs were killed to harvest jejunal samples. The results showed that WPC improved (P < 0.05) intestinal morphology, as indicated by greater villus height and villus height: crypt depth ratio, and intestinal barrier function, which was reflected by increased transepithelial electrical resistance and decreased mucosal-to-serosal paracellular flux of dextran (4 kDa), compared with the LPS group. Moreover, WPC prevented the LPS-induced decrease (P < 0.05) in claudin-1, occludin and zonula occludens-1 expressions in the jejunal mucosae. WPC also attenuated intestinal inflammation, indicated by decreased (P < 0.05) mRNA expressions of TNF-alpha, IL-6, IL-8 and IL-1 beta. Supplementation with WPC also increased (P < 0.05) TGF-beta 1 protein, phosphorylated-Smad2 expression and Smad4 and Smad7 mRNA expressions and decreased (P< 0.05) the ratios of the phosphorylated to total c-jun N-terminal kinase (JNK) and p38 (phospho-JNK: JNK and p-p38: p38), whereas it increased (P < 0.05) the ratio of extracellular signal-regulated kinase (ERK) (phospho-ERK: ERK). Collectively, these results suggest that dietary inclusion of WPC attenuates the LPS-induced intestinal injury by improving mucosal barrier function, alleviating intestinal inflammation and influencing TGF-beta 1 canonical Smad and mitogen-activated protein kinase signalling pathways.