Effects Of TLR4mAb On The Luminal And Mucosal Microbiotas In The Rats Model Of Ulcerative Colitis

Objective:To study the effects of TLR4 m Ab on the contents of Bacteroides,Enterococci, Lactobacilli, Bifidobacteria, Peptostreptococci and Escherichia coli in the luminal and mucosal microbiotas of rat models of ulcerative colitis(UC). Methods:30 SD rats were randomly assigned into the normal control group, model group or TLR4 m Ab group respectively. Trinitro benzene sulfonic acid(TNBs) was given to model group and TLR4 m Ab group, then TLR4 m Ab was given to TLR4 m Ab group by injection the same day. All the rats were killed on the 8th day to collect faecal and sigmoidmucosa specimens,and bacterial DNAs were extracted to determine the numbers of bacteria with real-time PCR.Results:Luminal microbiotas: the contents of Escherichia coli and Bacteroides in model group were significantly higher than in the control group(P<0.017), while those of Lactobacilli, Bifidobacteria and Enterococci decreased(P<0.017).There were no significant differences in the content of Peptostreptococci between model group and normal control group, and between the TLR4 m Ab group and model group.The contents of other target bacteria in TLR4 m Ab group were recovered(P<0.017), and the contents of the six bacteria in TLR4 m Ab group were not significantly different from those in normal control group.Mucosal microbiotas: there were no significant difference in the contents of Lactobacilli and Bifidobacteria between model group and control group, while the contents of other target bacteria increased(P<0.017).There were no significant differences in the contents of Lactobacilli and Bifidobacteria between TLR4 m Ab group and model group, while the contents of other target bacteria decreased(P<0.017). The content of Bacteroides in TLR4 m Ab group was higher than in control group, while the contents of other five bacteria had no obvious differences. Conclusion:There are significant changes in the luminal and mucosal microbiotas of rat models of UC, suggesting that the occurrence of UC is closely related to the changes of intestinal flora. TLR4 m Ab improved the structure of intestinal flora of UC rats, suggesting that TLR4 may play an important role in the occurrence of UC and regulation of the structure of intestinal flora. The contents of the target bacteria in luminal microbiotas are different from those in mucosal microbiotas, which suggests that the changes in the luminal microbiotas may not be consistent with the changes in mucosal microbiotas during the occurrence of UC.