Effects of Prebiotic Fructooligosaccharides on Cytokine and Tight Junction Protein Expression in Cultured Intestinal Epithelial Cells

Prebiotic molecules such as fructooligosaccharides (FOS) can promote the growth and metabolism of beneficial bacteria in the host intestine. There are several published studies suggesting that prebiotic supplementation can alleviate symptoms of colitis in animal models. In addition, a recent study showed evidence for direct effects of FOS on tight junction protein expression in cultured intestinal epithelial cells. This study aimed to assess effects of FOS on pro-inflammatory cytokine and tight junction protein expression in CMT-93 and Caco-2 colonic epithelial cells. Cells were treated with 0.1 mg/ml, 1 mg/ml or 10 mg/ml FOS and expression of cyclooxygenase-2 (COX-2), pro-inflammatory cytokines interleukin (IL)-1β and IL-6, and tight junction proteins claudin and ZO-1 were evaluated by real-time qPCR. The number of viable cells was analyzed after overnight exposure to FOS using a cell survival assay. Expression of ZO-1 and claudin and localization of nuclear factor kappa-B (NFkB) were evaluated by immunofluorescent staining. Surprisingly, FOS-treated CMT-93 cells showed a slight reduction in claudin mRNA expression compared to untreated cells. ZO-1 and COX-2 mRNA expression were not altered by FOS treatment compared to untreated controls. Immunofluorescent staining showed no translocation of NFkB to the nucleus after 2 hours of exposure to FOS. In conclusion, prebiotic fructooligosaccharides had minimal to no effects on the mRNA expression of claudin, ZO-1, and COX-2. In addition, FOS did not activate the NFkB pathway at the time points studied. These data suggest that FOS may not cause inflammatory responses in intestinal epithelial cells.