The role of obestatin in Roux-en-Y gastric bypass surgery in the obese, type 2 diabetes Zucker rat

Abstract

AimsRoux-en-Y gastric bypass (RYGB) is a novel therapy for diabetes and the exact mechanisms of this procedure remain unclear. Obestatin is an important gut hormone. We aimed to explore the role of obestatin in the therapeutic mechanism of RYGB. MethodsTwenty obese Zucker rats and twenty Wistar rats were randomly assigned to two groups: RYGB and sham surgery. We evaluated plasma obestatin and insulin levels pre- and post-RYGB. Additionally, obestatin expression levels in the gastrointestinal tract were assessed using immunohistochemical staining. ResultsIn Zucker rats, plasma obestatin and insulin levels gradually increased after RYGB. At post-operation week 7, plasma levels of obestatin were higher in the RYGB group than the sham operation group, and fasting plasma insulin levels were significantly increased the in RYGB group compared with the sham operation group. Furthermore, we observed a positive relationship between obestatin and insulin plasma levels. Among 10 zucker rats, high expression of obestatin was only seen in the jejunum of 2 rats before the operation; however, high expression of obestatin was seen in the Roux limb of 8 rats and in the ileum of 7 rats after RYGB. The expression of obestatin was significantly higher in the intestine in the RYGB group than the sham operation group postoperatively. ConclusionsWe propose that obestatin maybe a potential mediator to improve glucose homeostasis after RYGB. The increase of obestatin secretion may be an important mechanism through which RYGB alleviates obesity and type 2 diabetes mellitus.