L-theanine improves intestinal barrier functions by increasing tight junction protein expression and attenuating inflammatory reaction in weaned piglets
Xiaoling Chen, Lili Chen, Gang Jia, Hua Zhao, Guangmang Liu, Zhiqing Huang
Abstract
L-theanine, a characteristic non-protein amino acid first extracted from green tea leaves, has multiple biological functions, including antioxidant, immune and anti-inflammatory functions. However, the effect of L-theanine on intestinal barrier function of piglets remains unclear. This study aimed to investigate the role and underlying molecular mechanism of L-theanine in tight junction protein expression and intestinal mucosa inflammation in weaned piglets. Our data showed that L-theanine increased the expression of zonula occludens 1, claudin 1 and occludin in jejunum and ileum of piglets. In addition, L-theanine inhibited the mRNA expressions of tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β), IL-6 and Toll-like receptor 4 (TLR4) and the protein expressions of TNF-α, phospho-p38 MAPK (mitogen-activated protein kinase), phospho-IĸB and nuclear NF-ĸB (nuclear factor-ĸB) p65. Taken together, our results indicated that L-theanine could improve intestinal barrier function in weaned piglets, and the effect might be mediated through inhibition of the TLR4/p38 MAPK/NF-κB signaling pathway.