mRNA expression of TJ proteins in LPS-activated IPEC-J2 cells. (A) qRT-PCR analysis showed that LPS induced a decrease in mRNA expression of claudin-1 at 8, 12 and 24 h, while L. reuteri I5007 (LR) and L. reuteri I5007 culture supernatant (CS) effectively inhibited LPS-induced expression of claudin-1. (B) There was no change in occludin expression at 1 h, but a significant decrease after 4 h treatment with LPS. However, L. reuteri I5007 and its culture supernatant inhibited the decline. (C) LPS induced a distinct decrease in ZO-1 expression after 8 h, which was inhibited by L. reuteri I5007 and its culture supernatant. Results are represented as mean ± SEM, n = 3. *P < 0.05 vs. control cells, and #P < 0.05 vs. cells in the LPS group.