Background: There is accumulating evidence that obesity leads to a proinflammatory state, which plays crucial roles in insulin resistance and development of type 2 diabetes mellitus (T2DM). Previous studies demonstrated that weight loss after bariatric surgery was accompanied by a suppression of the proinflammatory state. However, the effect of bariatric surgery on the proinflammatory state and associated signaling beyond weight loss is still elusive. The objective of this study was to investigate the effect of duodenal-jejunal bypass (DJB) on glucose homeostasis, the proinflammatory state and the involving signaling independently of weight loss.
Methods: A high-fat diet and low-dose streptozotocin administration were used to induce T2DM in male Sprague-Dawley rats. The diabetic rats underwent DJB or sham surgery. The blood glucose, glucose tolerance and insulin resistance were determined to evaluate the glucose homeostasis. Serum insulin, GLP-1 and hsCRP were detected by ELISA. The gene expression of TNF-α, IL-6, IL-1β and MCP-1 in liver and fat was determined by quantitative real-time RT-PCR. The JNK activity and serine phosphorylation of IRS-1 in liver and adipose tissue were determined by Western blotting.
Results: Compared to the S-DJB group, DJB induced significant and sustained glycemic control with improved insulin sensitivity and glucose tolerance independently of weight loss. DJB improved the proinflammatory state indicated by decreased circulating hsCRP and proinflammatory gene expression in the liver and adipose tissue. The JNK activity and serine phosphorylation of IRS-1 in liver and adipose tissue were significantly reduced after DJB.
Conclusions: DJB achieved a rapid and sustainable glycemic control independently of weight loss. The data indicated that the improved proinflammatory state and decreased JNK activity after DJB may contribute to the improved glucose homeostasis.