Probiotics inhibit TNF-alpha-induced interleukin-8 secretion of HT29 cells.

Aim: To study the effect of probiotics on interleukin-8 secretion in intestinal epithelia when stimulated by proinflammatory cytokines.

Methods: Colonic adenocarcinoma HT29 cells were cultured and divided into four groups: control, TNF-alpha (group T in short), bifidobacterium (group B), lactobacillus (group L). B. Longum and L. bulgaricus were suspended in culture medium with a concentration of 1 x 10(8) cfu/ml and added into 24 wells respectively. One hour later TNF-alpha (10 ng/ml) was added into each well of groups T, B, L. The supernatants were collected and measured for IL-8 after 3 hours, nuclear factor-kappaB (NF-kappaB) p65 was also examined by Western blotting.

Results: There was less interleukin-8 secretion in HT29 cells when preincubated with B. Longum or L. bulgaricus compared with group T. Less p65 appeared in nuclei in groups B and L compared with group T, as detected by Western blot.

Conclusion: Probiotics can suppress interleukin-8 secretion in intestinal epithelia when stimulated by proinflammatory cytokines, which is most likely mediated by NF-kappaB.