mRNA expression of inflammatory cytokines in LPS-activated IPEC-J2 cells. IPEC-J2 cells were pre-treated with either L. reuteri I5007 (LR) or L. reuteri I5007 culture supernatant (CS) 2 h prior to LPS-activation. Quantitative RT-PCR (qRT-PCR) analysis was performed to determine the mRNA expression of inflammatory cytokines after 1, 4. 8, 12 or 24 h treatment with LPS. (A) LPS affected no change in TNF-α expression at 1 h, but significantly increased TNF-α expression during 4–24 h. However, both L. reuteri I5007 and its culture supernatant had no effect on TNF-α expression at the different time points in the absence of LPS, while they inhibited or prevented LPS-induced expression of TNF-α. (B) There were obvious increases in IL-6 expression during 8–24 h, but not 1–4 h induced by LPS, while L. reuteri I5007 and its culture supernatant produced no change at any time compared with control cells. L. reuteri I5007 and its culture supernatant inhibited or prevented LPS-induced IL-6 expression. Results are represented as mean ± SEM, n = 3. *P < 0.05 vs. control cells, and #P < 0.05 vs. cells in the LPS group.