Bypassing Different Parts of the Small Intestine Determines Different Metabolic Effects in Streptozotocin-Induced Diabetic Rats

Purpose Side-to-side jejunoileal bypass with proximal loop ligation (SSJIBL) has significant glucose-lowering and weight-control effects; however, no study has elucidated which segment is most effective in SSJIBL. This study investigated the effect of proximal small intestinal bypass (PSIB), middle small intestinal bypass (MSIB), and distal small intestinal bypass (DSIB) on metabolic improvement in streptozotocin (STZ)-induced diabetic rats. Materials and Methods STZ-induced diabetic rats were divided into four groups: PSIB, MSIB, DSIB, and sham-operated. The primary outcome measures were body weight, food intake, fasting blood glucose (FBG) levels, oral glucose tolerance (OGTT), insulin tolerance (ITT), serum insulin, gut hormones, serum lipid profile, and liver function levels. Results Global body weight in the DSIB group was lower than that in the PSIB group. The global food intake in the PSIB group was lower than that in the MSIB group. The PSIB group had a slightly better glucose-lowering effect than the MSIB and DSIB groups. The PSIB, MSIB, and DSIB groups all had improvement in insulin sensitivity at postoperative week 6. The MSIB group exhibited the best improvement in lipid homeostasis. Serum insulin and leptin levels were higher, and serum ghrelin levels were lower in the operated groups than in the sham group. Conclusions This study provides experimental evidence that PSIB surgery induces a better glucose-lowering effect than DSIB surgery, and MSIB induced the best improvement in lipid homeostasis, whereas DSIB was even more advantageous in terms of weight control in the STZ-induced diabetic rat model.