Effects of probiotics, probiotic DNA and the CpG oligodeoxynucleotides on ovalbumin-sensitized Brown-Norway rats via TLR9/NF-κB pathway

Abstract

The aim of the study was to investigate the effect of living probiotics, probiotic DNA and the synthetic oligodeoxynucleotides containing CpG motifs (CpG-ODN) on both immune response and intestinal barrier function in ovalbumin-sensitized rat and the underlying mechanisms. Brown-Norway rats were orally sensitized with ovalbumin, and living probiotics, probiotic DNA extraction, synthetic CpG-ODN or non-CpG ODN control was administered. In the living probiotics, probiotic DNA and CpG-ODN groups, the allergic response was significantly inhibited, the Th1/Th2 cytokine balance was shifted away from Th2 side, the percentage of CD4(+) CD25(+high) Treg cells was increased, and the intestinal barrier function was improved. The levels of toll-like receptor (TLR) 9 mRNA and nuclear factor (NF)-κB activity, as well as the IκB-α phosphorylation (p-IκB-α) was significantly increased in these three intervention groups compared with the OVA-positive group, whereas no such effects were found in the non-CpG ODN control group. These data show that the probiotic genomic DNA and the synthetic CpG-ODN was comparable with living probiotics in preventing food allergic response by immune modulation and intestinal barrier function enhancement, and the activation of TLR9/NF-κB signal pathway might be involved in this process.

Development and Characterization of an Effective Food Allergy Model in Brown Norway Rats

“…Finally, the study of gene expression on intestinal tissue could reflect changes induced locally by oral OVA administration. We found that the gene expression of RMCP-II was significantly increased in FA animals, and these results agree with serum concentrations of this mediator and also with changes reported concerning the gene expression of this molecule in mice and rats with food allergies [ 33 , 35 , 43 ]. However, surprisingly the gene expression of FcεRI did not change with FA induction, although it did after i.p.…”

“…In this latter condition, Knippels et al have demonstrated oral sensitization and have evaluated the influence of rat strain [ 30 ] and dosage [ 31 , 32 ]. However, the model of oral sensitization without an adjuvant requires a long process of sensitization (six weeks) and, although it has been used in several studies [ 33 – 36 ], success after oral sensitization was not always achieved in a high percentage of rats [ 37 ] and/or the sensitization does not always induce the synthesis of IgE antibodies [ 20 , 30 , 38 , 39 ]]. This limitation makes it difficult to use this model for the screening of new therapies or allergenicity studies.…”

Understanding the canine intestinal microbiota and its modification by pro‐, pre‐ and synbiotics – what is the evidence?

“…There is some evidence that even non‐viable probiotic bacteria can cause immune modulation in the host (Zhong et al . ). Also, there is very little information regarding possible interactions of strains in multi‐strain formulations; even though some studies in experimental rodents or humans show a synergistic effect on the measured outcome (Baillon et al .…”

Regulation of Intestinal Immune Responses through TLR Activation: Implications for Pro- and Prebiotics

“…Especially, since TLR activation on IEC affects the mucosal barrier function and potentially shapes mucosal immune responses in the intestine, interactions of allergens with TLR expressed by IEC may facilitate their entry into the gut mucosa and sustain the allergic inflammatory response. Interestingly, treatment with CpG oligodeoxynucleotides improved the intestinal barrier function and increased the percentage of T reg cells in the spleen and MLN (42). Since epithelial TLR may interact with the gut microbiota and luminal antigens, further understanding of the role of epithelial TLR activation in food allergy is necessary.…”