The Establishment Of Dysbacteria Model And The Influence To The Intestinal Physical Barrier

Objective:1. Establish different dysbacteria mice model based on intestinal dominant flora changes.2. Observe the changes of intestinal physical barrier of dysbacteria mice, to explore the interaction of intestinal dominant flora and intestinal mucosal immunity.Methods:1. Mice were dealed by intragastic administration of ceftriaxone sodium, according to the analysis of cecum flora, 5g/kg/d doses, 8 days to establish light-dysbacteria model ; 8g/kg/d doses, 8 days to establish heavy-dysbacteria model.2. Morphological changes of gastrointestinal mucosa were observed by optical microscope and transmission electron microscope, secreted IgA in intestinal mucosa were detected by ELISA, mucin2,mucin3 and defensin was detected by RT-PCR and immunohistochemical method.Results:1. In light-dysbacteria mice, intestinal dominant flora were decreased significantly, and in heavy-dysbacteria mice, intestinal dominant flora were almost dropped to naught.2. In dysbacteria mice, intestinal mucosal villus were damaged, villus were swell and breakage, the gaps of intestinal epithelial cells were wider, cells showed necrosis and vacuoles, lymph cells infiltrated mucosa layer, heavy-dysbacteria mice were damaged much better than light-dysbacteria mice. 3. Compared with normal mice, mucosal SIgA level was decreased in dysbacteria mice, the heavy-dysbacteria mice SIgA level were lower than light-dysbacteria mice.4. Compared with normal mice, the levels of mucin2, mucin3 and defensin were higher in dysbacteria mice, the heavy-dysbacteria mice higher than light-dysbacteria mice.Conclusion: Antibiotics of ceftriaxone sodium can inhibit and kill intestinal dominant flora; In dysbacteria mice, intestinal villus were damaged, the level of intestinal mucosal immunity was decreased, SIgA secretory volume was downtrend followed by dysbacteria degree; intestinal mucin and defensin levels were increased.