Changes of serum lipopolysaccharide, inflammatory factors, and cecal microbiota in obese rats with type 2 diabetes induced by Roux-en-Y gastric bypass.

Objectives: Previous studies have shown that Roux-en-Y gastric bypass (RYGB) leads to rapid regression of obesity and type 2 diabetes (T2D). However, the underlying mechanism remains unclear. This study aimed to investigate the effect of RYGB on serum lipopolysaccharide (LPS), interleukin (IL)-1, IL-6, tumor necrosis factor alpha (TNF-α), and cecal microbiota in obese rats with T2D.

Methods: Obese Sprague-Dawley rats with T2D were randomly divided into RYGB diabetes operation (DO; n = 8), diabetes sham operation (DS; n = 8), and diabetic control (DC; n = 8) groups. Healthy Sprague-Dawley rats were grouped as normal control (NC; n = 8). Fasting plasma glucose and body weight were measured. The levels of peripheral serum LPS, IL-1, IL-6, and TNF-α were measured by enzyme-linked immunosorbent assay. The rats were sacrificed 12 wk after operation. Subsequently, a superior mesenteric venous blood sample was taken to measure serum LPS levels by enzyme-linked immunosorbent assay. The cecal contents of the DO and DS groups were taken to extract metagenomic DNA per the genomic DNA standardization procedure. The V4 region of the 16 S rRNA was sequenced with the Illumina Hiseq sequencing platform to compare the structure and relative abundance of cecal microbiota between the DO and DS groups.

Results: Twelve weeks after operation in the DO group, fasting plasma glucose and body weight showed a significant decrease (P < 0.05). Moreover, the levels of peripheral serum LPS, IL-1, IL-6, and TNF-α were obviously decreased (P < 0.05). A change in the LPS level of superior mesenteric venous blood also revealed a dramatic decrease (P < 0.05). Additionally, RYGB resulted in a shift of cecal microbiota in obese rats with T2D.

Conclusions: Hypoglycemic effects after RYGB may be associated with improved levels of LPS, IL-1, IL-6, and TNF-α. Changes in the structure of cecal microbiota may also play an important role.