The Effects Of Lactobacillus On Mucous Cell And PPARγ In Colon Of Mice With Ulcerative Colitis

Objective:To investigate the effects of lactobacillus on mucous cell and the expression of mucin MUC2, PPARγin colonic mucosa of DSS-induced mice with Ulcerative Colitis (UC) to find its possible mechanism of treating UC.Methods:60 specific pathogen free, 7-8 week-old female BALB/C mice (weight 21.0±2.0g), were randomly divided into 6 groups: normal, lactobacillus treatment (high-dose), lactobacillus treatment (low-dose), positive control (mesalazine), negative control (excipient) and model groups, 10 mice were involved in each group. The normal group-mice were only fed with distilled water. Experimental colitis was induced by drinking 3% dextran sulfate sodium (DSS, MW: 36000-50000) freely for 7 consecutive days. At the same time, every experimental group was orally administrated lactobacillus (1×108CFU/ml), lactobacillus (1×107CFU/ml), mesalazine (27.8mg/ml), excipient (1.1mg/ml) respectively. The model group was given empty needle to insert stomach. In all animals, daily weight, stool trait and occult blood were recorded, and mice were killed on 8th day. Isolated the whole colon, and taken piece of distal colon for maldehyde fixed, paraffin-embedded, Hematoxylin and Eosin (H&E) staining, the rest of the colon were preserved at -70℃for reverse transcription-polymerase chain reaction (RT-PCR). The following indices were used for evaluation: disease activity index (DAI), colon length, histological scores; AB/PAS, immunohistochemistry, and RT-PCR were used to count the number of mucous cell, test the content of MUC2 protein and the level of MUC2, PPARγmRNA respectively.Results:1. BALB/C mice treated with DSS solution developed diarrhea and bloody stool, and DAI scores were increasing day by day. Lactobacillus decreased DAI scores. Compared with model group, the colon length of lactobacillus treatment (high-dose) group was statistically significant(P<0.05). In compared with normal group, it had no statistical significance(P>0.05).2. The histological scores in UC mice were higher than normal group's, but the scores of lactobacillus treatment (high-dose) group were lower than that of mesalazine group(P<0.05). The number of mucous cell and MUC2 protein were both decreased in colonic mucosa of UC mice compared with normal group(P<0.05), while they were increased in lactobacillus and mesalazine treatment groups, especially the high-dose lactobacillus treatment group(P<0.05). In colonic mucosa of UC mice, both MUC2 and PPARγmRNA were at a low level. The expression of MUC2 and PPARγmRNA were up-regulated after treated with lactobacillus. Moreover, the higher the dosage, the treatment of lactobacillus is better(P<0.05).Conclusion:The manifestations of DSS-induced acute colitis mice were similar to clinical symptoms of UC patients. Lactobacillus had therapeutic effects on the acute UC mice effectively. Its potential mechanism may be related to up-regulation of MUC2, PPARγand increasing the number of mucous cell in colonic mucosa.