Mouse Ileal Loop Model: A Surgical Model to Study Intestinal Permeability in the Mouse

Under pathological conditions, the disintegration of the epithelial and endothelial barriers increases intestinal permeability, causing the intestinal contents to leak into the surrounding vasculature and abdominal cavity. The intestinal permeability can be simulated using ileal loop model.

To begin, prepare an anesthetized mouse in the supine position. Make a midline incision in the abdomen. Place a sterile cotton gauze moistened with a suitable buffer over the surgical area to keep the organs hydrated during surgery.

Exteriorize the ileum — the distal part of the intestine — and spread it over the gauze to expose the mesentery. Identify two ligation sites in the ileum that are spaced appropriately in the mesentery and are devoid of any critical blood vessels. Then, pierce the mesentery to add ligatures at the identified sites.

Next, dissect the ileum to generate an isolated ileal loop with an intact blood supply and mesenteric membrane. Thereafter, inject a suitable buffer into the loop to flush the waste content.

Now, ligate the open ends of the ileal loop. Use a syringe to inject chemokine—a chemotactic protein suspension—into the loop, causing it to inflate. Return the organs to the abdomen.

Suture the incision. Allow the mouse to recover. Eventually, the chemokine molecules pass through the ileal wall into the adjoining blood vessels, causing inflammation and leukocyte influx.