Establishment of reproducible animal model by duodenal anastomosis

  Introduction: Sndi-Pnnute A. et al. proposed a duodenal anastomosis (SADI S) using sleeve gastrectomy. The advantages of SAID-S include the physiological advantages of a single anastomosis, no mesentery opening, pyloric preservation, and the "short circuit" of nutrient delivery from the stomach to the ileum. Until our research, there was no animal model to investigate this process, and we proposed a reproducible animal model SADIs.

   Method: Thirty-one adult male Wistar rats (12-16 weeks old) were included in this study. Under constant ambient temperature (23°C) and humidity, place all animals in individual cages and maintain a 12-hour light/dark cycle.

  Pre-operation preparation: The night before the operation, the rat was placed on an elevated wire platform to avoid fecal eating and fasting for about 12 hours; only water was allowed to eat freely. The isoflurane anesthesia box is used to induce anesthesia, and it is changed to intubation during anesthesia to maintain anesthesia. Enrofloxacin 2.5%, 25 mg/kg, intramuscular injection of antibacterial, 20 ml of saline subcutaneous injection (10 ml before operation, 10 ml after operation).

   Surgery: After induction, shave the hair from the sternum to the groin with an electric hair clipper, and place the rat on a heating pad in a dorsal position. The skin was disinfected with iodophor aqueous solution. After the xiphoid process was identified, a 5cm midline abdominal incision was made with an 11 surgical scalpel. After identifying the white line, use an electric knife to make a midline incision in the abdominal wall. Then expose the abdominal cavity with surgical instruments. A large curvature gastrectomy was completed with surgical scissors. After the 4 absorbable sutures were ligated, the gastrosplenic ligament was cut into sections, and the duodenal incision was continued. Next, use an 8FR catheter to make an incision from the mouth to the duodenum or from the outside of the duodenum. Perform a standard sleeve gastrectomy around the 8FR catheter using a blue reloadable laparoscopic stapler. The length of the small intestine is measured from the junction of the ileum and colon. It is about 30% of the total length of the intestine; about 35 cm. This point is the location of the future duodenal anastomosis. Three methods are used for duodenal separation and duodenal anastomosis:

  1. Use 3.0 non-absorbable risk for ligation from the pylorus 5mm from the duodenum, and use absorbable 6.0 sutures for continuous side-to-side duodenal anastomosis.

  2. Use a non-absorbable surgical clip for ligation from the pylorus 5mm from the duodenum, and use absorbable 6.0 sutures to perform side-to-side duodenal anastomosis continuously.

  3. Make an incision from the pylorus 5mm away from the duodenum, and continuously suture the duodenal stump with non-absorbable 6.0 sutures to perform end-to-side duodenal anastomosis with absorbable 6.0 sutures. After the anastomosis, we used 3 consecutive non-absorbable sutures to return the intestine to the abdominal cavity and close the abdominal muscles. Close the abdominal skin intermittently with non-absorbable 4.0 sutures.

   Post-operative care: Immediately after the operation, each rat recovered under a heat lamp, and continued monitoring until regaining consciousness. After recovery, the animal was isolated and transferred to a cage, placed on a raised wire platform, and fasted for the first 24 hours. Provide liquid diet for the next 3 days. Antibiotic (enrofloxacin) was administered for 72 h. On the 7th day, a solid diet is given, and the transition period is 3 days. During this period, we provide both liquid and solid diets. At the end of the study, the rats were decapitated and sacrificed after exploratory laparotomy under isoflurane anesthesia. Take the brain for immunohistochemical study and measure neuronal activity. The operation time and death from anesthesia were recorded. During the study, our goal was to validate the technique with rats for 2 weeks. The weight was recorded before and every day after the operation, and every death was investigated to determine complications. After 2 weeks, a laparotomy was performed to determine the fistula, intestinal obstruction, or repermeability of duodenal defecation.

  Result: The average operation time is 40±15 min. There is no significant difference between the three surgical methods. The average initial weight of the rats was 344±34g (range 263-475 g), and the average postoperative weight was 261±42 g (195-391 g). Six cases died, one of which was secondary to anesthesia overdose. The other five deaths were caused by Anastomotic leakage occurred on the first day and the seventh day after the operation; three cases of anastomotic leakage occurred in the side-to-side anastomosis group. During the 2-week laparotomy, we found two anastomotic abscesses (1 side-to-side group) And 1 side-to-side anastomosis group), 4 cases of duodenal defecation recanalization (3 cases of non-absorbable sutures, 1 case of surgical clips)..

   Conclusion: As far as we know, we are the first study to evaluate the feasibility of the SADI-S. animal model. We chose the Wistar rat because it is the most commonly used species for preclinical studies of obesity and diabetes.