L-theanine attenuates H 2 O 2-induced inflammation and apoptosis in IPEC-J2 cells via inhibiting p38 MAPK signaling pathway

This study investigated the protective effects of L-theanine on hydrogen peroxide (H 2 O 2 )-induced intestinal barrier dysfunction in IPEC-J2 cells. Results showed that L-theanine reduced H 2 O 2 -induced IPEC-J2 cells inflammation and apoptosis, and decreased protein phosphorylation levels of p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor kappa -B (NF- kappa B). The p38 MAPK inhibitor (SB203580) decreased oxidative stress, the protein expression of phosphorylation of p38 MAPK and NF- kappa B, the H 2 O 2 -induced increase in mRNA expression of pro-apoptotic and pro -inflammatory related genes expression and secretion, and tight junction protein related genes expression, which was similar to the effect of L-theanine. In conclusion, L-theanine inhibited H 2 O 2 -induced oxidative damage and inflammatory reaction, eliminated apoptosis, and protected intestinal epithelial barrier damage by inhibiting the activation of p38 MAPK signaling pathway.