Roux-en-Y gastric bypass in mice--surgical technique and characterisation.

A reproducible Roux-en-Y gastric bypass (RYGB) model in mice is needed to study the physiological alterations after surgery. Male C57BL6 mice weighing 29.0 ± 0.8 g underwent either RYGB (n = 14) or sham operations (n = 6). RYGB surgery consisted of a small gastric pouch (~2 % of the initial stomach size), a biliopancreatic and alimentary limb of 10 cm each and a common channel of 15 cm. Animals had free access to standard chow in the postoperative period. Body mass and food intake were recorded for 60 days. Bomb calorimetry was used for faecal analysis. Anatomical rearrangement was assessed using planar X-ray fluoroscopy and computed tomography (CT) after oral Gastrografin® injection. RYGB surgery led to a sustained reduction in body weight compared to sham-operated mice (postoperative week 1: sham 27.8 ± 0.7 g vs. RYGB 26.5 ± 1.0 g, p = 0.008; postoperative week 8: sham 30.7 ± 0.8 g vs. RYGB 28.4 ± 1.1 g, p = 0.003). RYGB mice ate less compared to shams (sham 4.6 ± 0.2 g/day vs. RYGB 4.3 ± 0.4 g/day, p < 0.001). There were no differences in faecal mass (p = 0.13) and faecal energy content (p = 0.44) between RYGB and shams. CT scan demonstrated the expected anatomical rearrangement without leakage or stenosis. Fluoroscopy revealed rapid pouch emptying. RYGB with a small gastric pouch is technically feasible in mice. With this model in place, genetically manipulated mouse models could be used to study the physiological mechanisms involved with metabolic changes after gastric bypass.