All operations reported in this study were performed by one surgeon (MB). Prior to the start of the experiments the surgeon practiced the procedure on 60 cadaveric rats which resulted in the following surgical protocol.
After 1 week of acclimatization rats were randomized to gastric bypass or sham operation. Rats were fasted overnight with water available ad libitum. Before surgery, rats were weighed, and then anesthetized with isofluorane (4% for induction, 3% for maintenance). Preoperatively, gentamicin 8 mg/kg and carprofen 0.01 ml were administered intraperitoneally (ip) as prophylaxis for postoperative infection and pain relief. Surgery was performed on a heating pad to avoid decrease of body temperature during the procedure. Prior to a midline laparotomy, the abdomen was shaved and disinfected with surgical scrub. In the sham group a 7 mm gastrotomy on the anterior wall of the stomach with subsequent closure (interrupted prolene 5-0 sutures) and a 7 mm jejunotomy with subsequent closure (running prolene 6-0 suture) was performed. In the gastric bypass group, the proximal jejunum was divided 15 cm distal to the pylorus to create a biliopancreatic limb (Figure 1, A). After identification of the caecum (Figure 1, D), the ileum was then followed proximally to create a common channel of 25 cm (Figure 1, C). Here, a 7 mm side-to-side Jejuno-Jejunostomy (running prolene 7-0 suture) between the biliopancreatic limb and the common channel was performed.
The two techniques described below in this paper relates to how the stomach was transected close to the gastro-oesophageal junction to create a small gastric pouch with no more than 3 mm of gastric mucosa left. The gastric pouch and alimentary limb was anastomosed (Figure 1, B) end-to side using a running prolene 7-0 suture. The gastric remnant was closed with interrupted prolene 5-0 sutures. The complete bypass procedure lasted approximately 60 minutes and the abdominal wall was closed in layers using 4-0 and 5-0 prolene sutures. Approximately 20 minutes before the anticipated end of general anesthesia, all rats were injected with 0.1 ml of 0.3% buprenorphine subcutaneously to minimize postoperative discomfort. Immediately after abdominal closure, all rats were injected subcutaneously with 5 ml of normal saline to compensate for intraoperative fluid loss. After 24 hours of wet diet (= normal chow soaked in tap water), regular chow was offered on postoperative day 2. Figure 1 shows a schematic illustration of the intestinal anatomy before and after gastric bypass surgery.