Alterations of the Microbiological Profile of the Gut Microbiota Inantigen Specific Chronic Inflammatory Bowel Disease in the Mouse

Background:The gastrointestinal tract sustains a complex ecosystem formed by the interaction between the resident microbiota and the cell lining of the mucosal epithelium. This interaction is essential for the maintenance of the intestinal homeostasis. The microbial imbalance on the body surfaces due to factors such as inflammatory bowel disease,chronic fatigue syndrome, obesity,  cancer and colitis is termed Dysbiosis. The aim is investigate, in the mouse model,if alterations of the microbiological profile of gut microbiotaare observed in antigen specific chronic inflammatory bowel disease.Methods:C57Bl/6 adult, male mice received either two inoculations of 100μg Peanut Protein Extract (PPE) or saline. 10 days after each inoculation,bloodwas obtained from all animals to determine anti-peanut-specific antibodies. 21 days after the booster inoculation half of the animals of each group received a Challenge Diet (CD)for 30 days, containing exclusively raw peanut while the other half continued to eat mouse chow. On the last day of the experiment all animals were euthanized with an overdose of anesthetics. After a macroscopic inspection of the peritoneal cavity, gut samples were retrieved for both histological and microbiological analysis. The bacterial profile was determined using the DcodeTM Universal Mutation Detection System (BioRad Laboratories, UK).Results:Animals that received PPE inoculation presented significantly higher anti-peanut antibodies compared to saline inoculated animals, irrespective of their diet.The histological analysis of the PPE inoculated animals that ate peanuts showed significant alterations of the mucosal architecturewhen compared to all other 3 groups: reduction of the villi number, shortening of the villiand increase in the mononuclear cell infiltrate in the epithelial layer and lamina propria.  The qualitative analysis of the bacterial profile showed a significant shift inPPE inoculated animals challenged with a peanut diet when compared to all other 3 groups. We are currently undertaking the quantitative analysis to determine which components of the mouse microbiota alter most. Conclusions:the antigen specific chronic inflammatory bowel disease, developed by our group,is a good model to study the microbial shift of the gut microbiotaduring food allergies.