TLR2McAb and TLR4McAb decrease inflammatory cytokines expression and increase counts of Lactobacilli and Bifidobacteria in dextran sulfate sodium-induced colitis in mice

Abstract

Objective To evaluate the effect of TLR2McAb and TLR4McAb on intestinal flora of DSS-induced colitis in mice. Methods Fifty healthy male BALB/c mice (SPF level), were randomly assigned into five groups: the control group( group A), the UC model group( group B), TLR2McAb intervention group( group C), TLR4McAb intervention group( group D) and TLR2McAb + TLR4McAb intervention group(group E). Clinical symptoms were evaluated by the disease activity index(DAI), while tissue sam ples were evaluated by histological scoring(HS). The quantities of mRNA for IFN-γ, IL-4 and IL-17 were determined by real-time PCR. Meanwhile, fecal samples were obtained directly from the cecum for microbiological studies. Results After the treatment with TLR2McAb and TLR4McAb, DAI and HS were decreased significantly. Compared with group A, inflammatory cytokines such as IFN-γ, IL-4 and IL-17 in group B were higher. Compared with group B, expression of these three cytokines in group C to E was all markedly decreased. Group A showed a considerable predominance of Lactobacillus spp and Bifidobacterium spp,while the UC model group showed a conspicuous increase of Escherichia coli and decreases of Lactobacillus spp and Bifidobacterium spp. After treatment with TLR2McAb or/and TLR4McAb, Lactobacillus spp and Bifidobacterium spp increased to the normal level. But counts of E. Coli in the three intervention groups were not changed. Conclusion TLR2McAb and TLR4McAb suppressed the development of DSS-induced colitis and increase cecum counts of Lactobacilli and Bifidobacteria. Key words: Ulcerative colitis; TLR2 monoclonal antibody(TLR2McAb); TLR4 monoclonal antibody (TLR4McAb); Intestinal flora