Postoperative Ileus Murine Model

The scope of our study is intestinal immunity. We are trying to illustrate the pathophysiology and the mechanism of POI injuries for the development of novel therapies. One challenge is to establish consistent and reproducible experimental models of POI in mouse.

This involve controlling the variables such as surgical techniques and assessing protocols in animal care to minimize variability between experimental groups. Another challenge is illustrating the underlying pathophysiological mechanisms of POI in mouse. Our protocol aims to establish a reproducible model with minimal variation for studying the pathophysiology of POI and evaluating new anti-inflammatory strategies.

Our goal is to bridge the gap between preclinical findings in mouse models, and that there are clinical relevance in humans, thereby enhancing the potential for experimental outcomes to translate into effective treatments for POI. To begin, position the anesthetized mouse on the surgical platform. Use an electric hair shaver to remove hair from the abdomen.

Then use a saline moistened cotton ball to wipe off all loose hair on the abdomen. Fully extend the limbs to expose the abdomen and position the mouse's head to maintain a clear airway. Then using a cotton ball soaked in 75%alcohol, disinfect the skin of the surgical area twice.

After that, use a dry sterile medical gauze to remove excess alcohol from the abdomen. Next, make an incision through the skin. Using tweezers, lift the rectus abdominis muscle in the middle of the abdomen and make a small incision along the median line.

Ensure the incision's upper margin is six to eight millimeters from the xiphoid process of the sternum, and the lower margin is six to eight millimeters from the external genitalia. Then place gauze premoistened with normal saline on both sides of the abdominal incision. Fix the gauze with hemostatic forceps on the upper and lower edges of the incision to expose it.

After fixing the gauze properly, press gently against both sides of the abdominal wall with two saline moistened cotton swabs. Then squeeze out a small amount of the intestinal tube through the in incision and place it on the gauze to expose it. Locate the cecum.

And take out the intestine with saline moistened cotton swabs until two centimeters before the stomach to avoid touching the pancreas. Extend the intestine from the proximal end of the pancreaticoduodenal ligament to the distal end of the ileocecal region. Then apply consistent pressure along the entire small intestine from the proximal to the distal for five minutes until small bleeding spots emerge.

After that, use pre-moistened cotton swabs to carefully place all the small intestines back into the abdominal cavity. Then gently massage the abdomen across the gauze and abdominal wall for three to five seconds to ensure normal bowel position and prevent post-surgery obstruction or torsion. Next, inject 100 microliters of saline into the abdominal cavity to replace lost fluids and lubricate the abdominal tissue.

Then remove the gauze and perform a two layer closure at the abdominal incision. After suturing, gently wipe the area near the abdominal incision with dry sterile medical gauze to keep it dry and clean from blood, tissue fluid, or normal saline. Apply a small amount of medical incision adhesive to and around the incision to avoid splitting after surgery.

Once the adhesive has dried, place the mouse on a heated blanket at 37.5 degrees Celsius and monitor the mouse until it fully recovers.