The overall goal of this procedure is to assess the localized intestinal integrity in animal models of gastrointestinal disease.This method can help answer key quesitons about gastrointestinal disease, such as whether musosal integrity is lost or if there is an increase in uptake of a specific molecule or bacteria during disease.The main advantage of this technique is that it can be used to assess specific areas within the gastrointestinal tract.To prepare the gastrointestinal tract, begin by spraying the abdomen and thorax of the mouse with 70 percent ethanol and use scissors to make a horizontal incision in the middle of the abdomen, to expose the peritoneum.Next, cut the upper small intestine from the stomach at the pyloric sphincter and the large intestine at the anal verge.Then use forceps to gently remove the mesentery and place the intestinal tract in prewarmed, oxyginated medium.Identify the area to be assessed for permeability, measuring the sections of the duodenum and jejunum relative to the stomach in the sections of the colon and ilium relative to the cecum to maintain consistency between the experimental animals.Note the presence of mucosa associated lymphoid tissues such as Peyer's patches, which can be identified as small nodules on the sarosal side of the lumen.Then, cut the selected section and use a 1 ml syringe to gently flush the lumenal contents of the segment into a petri dish containing 37