Lactobacillus plantarum inhibited the inflammatory response induced by enterotoxigenic Escherichia coli K88 via modulating MAPK and NF‐κB signalling in intestinal porcine epithelial cells

To investigate the effects of Lactobacillus plantarum on inflammatory responses induced by ETEC K88 and explore the underlying molecular mechanisms. Intestinal porcine cells (IPEC‐1) were incubated with 0 or 1 × 108 CFU per well L. plantarum for 4 h, and then these cells were challenged with 0 or 1 × 108 CFU per well ETEC K88 for 2 h. The results showed that pre‐treatment of IPEC‐1 cells with L. plantarum prevented the increases in the transcript abundance of interleukin‐1α (IL‐1α), interleukin‐6 (IL‐6), interleukin‐8 (IL‐8) and tumour necrosis factor‐α (TNF‐α) (P < 0·05) caused by ETEC K88. Additionally, L. plantarum inhibited the reduction in peroxisome proliferator‐activated receptor‐γ (PPAR‐γ) expression caused by ETEC K88 (P < 0·05). Moreover, L. plantarum pre‐treatment downregulated the phosphorylation levels of c‐Jun N‐terminal kinase (JNK), extracellular regulated protein kinases 1 and 2 (ERK1/2) and p38 and the nuclear concentration of nuclear factor kappa B p65 (NF‐κB p65) (P < 0·05) compared with ETEC K88 group. Silencing experiment further supported that the protective effect of L. plantarum P might mediated by suppression of ETEC‐provoked activation of MAPK and NF‐κB signalling pathways. Lactobacillus plantarum inhibited the inflammatory response induced by ETEC K88 in IPEC‐1 cells via modulating MAPK and NF‐κB signalling. This study elucidated the underlying mechanism in which probiotics protect against intestinal inflammation caused by ETEC K88.