A Murine Model of Vertical Sleeve Gastrectomy

The overall goal of this procedure is to model the health benefits of vertical sleeve gastrectomy in mice. This method can help answer key questions in obesity research about the mechanisms by which bariatric surgery improves obesity and obesity comorbidities. The advantage of this technique is that it provides a model for studying these mechanisms which will facilitate identification of novel targets for the treatment of obesity and its comorbidities.

Before beginning the procedure, apply veterinary ointment to the eyes of an anesthetized mouse and place the mouse on a heating pad. Remove the hair from the umbilicus to the axilla gently holding the skin taught to avoid skin lesions and use cotton-tip applicators to sequentially disinfect the exposed skin with povidone-iodine and ethanol. Wearing sterile gloves and using sterile technique, place sterile surgical drapes on either side of the animal.

Cut a small hole in the foil to allow access to the mouse's abdomen and use a piece of autoclaved aluminum foil as a surgical drape. Make a skin incision from the mid abdomen to the xiphoid cartilage. Under a dissecting microscope, use iris scissors to cut through the body wall along the linea alba.

And use new cotton-tip applicators to gently elevate the stomach out of the abdomen. Bluntly dissect the greater omentum from the greater curvature of the stomach. Then use 7-0 monofilament absorbable sutures to place two ligatures around the short gastric artery that runs between the fundus of the stomach and the spleen.

When both ligatures have been placed, use spring scissors to cut between the two sutures and fully exteriorize the stomach from the abdominal cavity. Place gauze under the stomach and hydrate the organ with saline. For a sham procedure, use a 6-0 monofilament absorbable suture with a taper needle to place a loose simple continuous pattern starting two millimeters to the right of the esophagus along the ventral gastric wall and continuing along the dorsal gastric wall.

Make sure the suture lies flat without restricting the stomach and use three to four throws to gently tie off the suture. For a vertical sleeve gastrectomy procedure, use a 7-0 monofilament absorbable suture with a taper needle to ligate the prominent branches of the gastric artery and vein just below the intended line of transection. Place a simple continuous line of 6-0 monofilament absorbable suture through both gastric walls just below the intended line of transection to prevent spillage of the gastric contents.

Place thin-tipped hemostats above the suture line and use spring scissors to cut between the suture line and the hemostats. Remove the transected gastric tissue from the sterile surgical field and use fresh cotton-tip applicators to clean the blood and digesta from the stomach. Use a 6-0 monofilament absorbable suture with a taper needle to reinforce the apposition of the gastric walls in a simple discontinuous pattern.

Using a 20-gauge gavage needle attached to a 20-milliliter syringe, perform gastric lavage with fresh saline and securely close the stomach with a minimum of 20 knots. Then gently press the stomach with a cotton applicator to test for leaks. If no leaks are detected, lavage the stomach with at least 60 more milliliters of fresh saline to remove any infectious particulates.

After either procedure, use a cotton-tip applicator to return the stomach under the liver within the abdominal cavity and place an applicator along the dorsal aspect of the abdominal cavity to absorb any excess fluid. Use a blunt 18-gauge needle to inject lactated Ringer's solution with our without antibiotics directly into the abdominal cavity and use 6-0 monofilament absorbable sutures to close the abdominal muscle layer in a simple discontinuous pattern and the skin layer in a simple continuous pattern. Then place tissue adhesive on the skin and fold the skin over the suture line to protect the suture from disruption by the animal.

Vertical sleeve gastrectomy operated, high-fat-diet fed mice exhibit a reduced energy intake and body weight compared to ad libitum fed, sham operated mice. Vertical sleeve gastrectomy improves glucose tolerance, increases glucose stimulated insulin secretion and increases postprandial glucagon-like peptide one secretion compared to sham operated, ad libitum fed control mice consistent with outcomes observed in humans and other rodent models of bariatric surgery. Once mastered, this procedure should be performed in 90 minutes.

While learning this procedure it is important to remember to be gentle when manipulating the gastrointestinal tract. The GI tract is a very sensitive organ in mice and accidental manipulation of the small intestine can lead to GI stasis. After successfully learning this procedure, researchers can apply genetic or pharmaceutical manipulations to various disease models to investigate the mechanisms by which bariatric surgery improves health.