2b). The ‘patchiness’ of the lesions complicated the scoring and, as a consequence, no
significant differences in histological scoring could be observed between the treatment groups (Table 1). Similarly, cytokine analysis by qRT-PCR did not reveal significant differences (data not shown). As described above, in the 3% DSS-induced model the epithelial layer was severely damaged with patchy lesions (Fig. 2b), and the administration of LGG wild-type was shown to be detrimental, in contrast to administration of the dltD selleck chemicals llc mutant (Fig. 2a and Table 1). Because Yan et al.  reported that the intestinal epithelial cells are an important target for certain probiotic actions of LGG, we investigated subsequently whether the detrimental effect of LGG wild-type and the enhanced efficacy of the dltD mutant correlated with the integrity of the intestinal barrier. Hereto, C57/BL6 mice received 1% DSS for three cycles of 7 days DSS–7 days normal drinking water. LGG
wild-type and dltD mutant were then given in the drinking water starting 3 Ibrutinib order days before colitis induction. In this model, there was no significant difference in body weight between the PBS-, wild-type- and dltD-treated groups (Fig. 2c). However, the dltD-mutant treated group showed a significantly attenuated colonic inflammation based on the macroscopic score (Table 2). In this milder model, epithelial damage was much less pronounced than in the 3% DSS-induced model, although colitis lesions were still clearly visible (Fig. 2d). Interestingly, the LGG wild-type also showed a trend of ameliorating the severity of the colitic parameters in this mild chronic model, although no significant difference could be observed compared to the PBS-treated group. qRT-PCR results revealed that the administration of the dltD mutant reduced mucosal IL-12p40 mRNA expression compared to the PBS-treated (P = 0·0170) and LGG wild-type-treated groups (P = 0·0363) (Fig. 3a).
IFN-γ expression was also reduced in the dltD-treated group and this was significant compared to the PBS-treated group (P = 0·0276) (Fig. 3b). As these differences in cytokine expression might be downstream Idelalisib supplier effects of a different TLR expression, we subsequently determined TLR-1, TLR-2, TLR-4 and TLR-6 mRNA expression in the three treatment groups. Mice treated with the dltD mutant showed a reduced expression of TLR-2 compared to PBS-treated mice (P = 0·0006) (Fig. 3c). Compared to LGG wild-type-treated mice, we also observed lower expression levels of TLR-1 (P = 0·0179), TLR-2 (P = 0·0328) and TLR-4 (P = 0·0443) in the dltD treated group (Fig. 3c–e). No significant differences in cytokines TNF, IL-1β, IL-10 and TGF-β were seen (data not shown). Also no significant changes in expression of TLR-6 (Fig. 3f) were observed between the three treatment groups.