Modified Roux-en-Y gastric bypass surgery avoids complications in mice

Abstract

Background: Roux-en-Y gastric bypass（RYGB）surgery delivers an improvement in obesity and obesity-related risks. However, due to the limited operational space in the abdominal cavity of mice, the technical complexity of RYGB surgery and the postoperative complications hinder its mechanism research. The aim was to develop a device that makes it easier to anastomose the esophagus to the jejunum.

Methods: We have invented a simple gastrointestinal anastomosis auxiliary device consisting of a rigid front end and a flexible rear end. Thirty male C57BL6J mice were subjected to RYGB with an auxiliary device. Postoperative recovery and survival status of mice were evaluated using body weight, food intake, body fat, and glucose tolerance.

Results: Based on the RYGB surgical methodology reported in previous literature, the anastomosis device described in this article assists in end-to-end anastomosis of the esophagus and jejunum, which reduces surgical difficulty and time. CT scan results revealed that, following a short - term recovery period after mRYGB surgery, no leakage or stenosis was detected at the anastomotic site in the mice. Moreover, after postoperative recovery, there was no significant difference in food intake, weight and body fat distribution compared with Sham mice, but the glucose tolerance of mRYGB mice was significantly improved.

Conclusions: Our modified RYGB surgical method can effectively avoid the problems of anastomotic leakage and stenosis in mice and improve long-term quality of life.

Fig 1. RYGB in the mice.

A, Experimental flow chart. Mice were fasted overnight before surgery and injected with penicillin 30 min before surgery. After surgery, mice were placed on a heating pad, followed by a fluid diet 72h later and a solid diet 7 days later. B, Schematic representations of anastomotic device. The right panel showed the esophagus and jejunum. C, mRYGB (RYGB with anastomotic devices) in the mice. (a,b) After scraping and disinfecting the abdominal skin, the mice were draped to expose the surgical. (c) A retractor was placed to expose the abdomen. At the jejunum 4–6 cm away from the ligament of Treitz, an indicative suture was placed to mark the end of the Roux limb, and then the jejunum was transected at this marked point. (d) The perigastric ligaments and blood vessels were separated and ligated to release the stomach. (e-h) The gastroesophageal junction was transected at the cardia. The rigid part of the XL anastomotic device was inserted into the esophagus, and the flexible part into the intestinal cavity. Along the surface of the anastomotic device, the lower esophagus and the distal jejunum were end-to-end anastomosed. (i,j) The XL anastomotic device was taken out at a small incision 4–6 cm away from the gastrointestinal anastomosis. (k) Then the jejuno-jejunostomy was performed between the incision mentioned above and the proximal jejunum. (l,m) The muscle layer and skin were sutured separately to close the abdominal cavity. (n)After surgery, mice were injected with meloxicam (1 mg/kg) and then placed on a heating pad. D, Percent survival of sham, RYGB and mRYGB surgery performed by three surgeons. Mice were weight-matched and performed for Sham, RYGB, and mRYGB surgery (n = 10). E, Complication of sham, RYGB, and mRYGB surgery (n = 30).

Fig 2. The status of gastroesophageal anastomosis after mRYGB surgery.

A, PET-CT representative diagram of the esophagojejunal anastomotic site. The red arrow points towards the esophagojejunal anastomosis site. B, Representative morphological images of the esophagojejunal anastomotic site. C, Representative images of hematoxylin–eosin staining esophagojejunal anastomosis site of the mRYGB mice.

Fig 3. RYGB combined with anastomotic devices (mRYGB) improves the quality of life in mice.

A and B, The food intake (A) and time courses of body weight (B) in sham and mRYGB surgery mice (n = 6). C, Representative Micro-CT image of sham and mRYGB surgery mice. D, Visceral and subcutaneous fat volume and relative volume to body weight in mice after sham and mRYGB surgery (n = 6). E and F, Blood glucose levels during intraperitoneal and oral glucose tolerance tests performed on sham and mRYGB surgery mice(n = 5). The areas under the curve of each group are shown on the right. The data are presented as the mean ± SEM. *p < 0.05, **p < 0.01.