Surgical Models of Gastroesophageal Reflux with Mice

The overall goal of this procedure is to create gastroesophageal reflux models in mice. First, the preparation of a gastric reflux model is shown next, the setup of a mixed reflux model is presented, followed by the demonstration of the preparation of a duodenal reflux model. Ultimately, the degree of esophageal damage induced by the different reflux models can be assessed by histological analysis.

Generally, individuals new to this medicine will struggle because of the small size of the mouse esophagus To set up the gastric reflux model. After confirming the proper level of anesthesia by toe pinch, use hair clippers to shave the surgical area and apply ointment to the animal's eyes. Using Betadine solution, sterilize the exposed skin.

Then make a two centimeter upper midline incision starting from the xiphoid process down toward the anus. Next, open up the abdominal cavity through the midline and use a pair of scissors to remove the xiphoid. Separate and cut the connective tissues between the liver and the stomach.

Then ligate and sever the vessel bundle between the spleen and the fundus. When the fundus has been completely freed, turn the tissue slightly to the left to expose the left side of the gastroesophageal junction. Then using a sharp pair of scissors, make a five millimeter longitudinal incision on the muscle along the distal esophagus to expose the epithelium.

Open the epithelium in the same direction with three incisions to cut off most of the four stomach. Next, using a taper point needle place an eight O proline suture, first through the esophagus and then through the four stomach with accurate mucosal to mucosal opposition. A six oh proline suture is used in this demonstration in order to improve his ability, continue to place evenly spaced sutures, three to four millimeters apart from the esophagus through the four stomach until the entire area is ligated from point to point as illustrated after the last suture has been placed, use normal saline to clear the abdominal cavity of any blood and remaining gastric contents.

Then close the abdominal wall with silk sutures and the skin with metal clips to set up the mixed reflux model. After exposing the gastroesophageal junction as just demonstrated, gently separate the dorsal side of the esophagus from the blood vessels behind the esophagus. Pass a small cotton tip between the esophagus and blood vessels.

Then make two five millimeter longitudinal incisions on the gastroesophageal junction and two five millimeter longitudinal incisions on the anti mesenteric border along the proximal end of the duodenum, adjacent to the pylori. Next, using interrupted ATO prolene sutures, placed three to four sutures on the dorsal side and two to three sutures on the front side to anastomosis the incisions with accurate mucosal to mucosal opposition. Then remove the cut tip, wash the abdominal cavity with normal saline and close the abdominal wall and skin as just demonstrated to set up the duodenal reflux model.

After preparing a mixed reflux model as just demonstrated, carefully lift the stomach to expose the backside of the tissue, then expose the blood vessels on the dorsal side of the esophagus, ligate and cut the blood vessels, ligate the duodenum at the pori and ligate, and cut the mesenterium as well. Then remove the whole stomach, wash the abdominal cavity with normal saline and close the abdominal wall and skin. At the completion of each of the surgeries, place the animals on a heating pad with monitoring until they, they're fully recovered at four weeks post-surgery, the architecture of the esophageal epithelium will exhibit damage from the reflux as observed in these images of the upper digestive tract.

In mice with gastric mixed or duodenal reflux, the epithelium becomes thicker and the papilla elongates compared to control animals, hyper proliferation of the epithelial cells, and infiltration of the upper digestive tract by inflammatory cells. Common signs of esophagitis are observed in the reflux model. Animals as well Once mastered this technique can be done in 20 to 30 minutes if it is performed properly.