Protective effects of Lactobacillus plantarum on epithelial barrier disruption caused by enterotoxigenic Escherichia coli in intestinal porcine epithelial cells

•L. plantarum partially offset ETEC-K88 induced upregulation of inflammatory cytokines.•L. plantarum protected against epithelial barrier damage from ETEC-K88.•The protective effects of L. plantarum likely involve diminished activation of NF-κB and MAPK pathways. Tight junctions (TJs) play an important role in maintaining the mucosal barrier function and gastrointestinal health of animals. Lactobacillus plantarum (L. plantarum) was reported to protect the intestinal barrier function of early-weaned piglets against enterotoxigenic Escherichia coli (ETEC) K88 challenge; however, the underlying cellular mechanism of this protection was unclear. Here, an established intestinal porcine epithelia cell (IPEC-J2) model was used to investigate the protective effects and related mechanisms of L. plantarum on epithelial barrier damages induced by ETEC K88. Epithelial permeability, expression of inflammatory cytokines, and abundance of TJ proteins, were determined. Pre-treatment with L. plantarum for 6h prevented the reduction in transepithelial electrical resistance (TEER) (P