Changes of serum lipopolysaccharide and cecal flora in type 2 diabetic rats induced by Roux-en-Y gastric bypass

Abstract

Objective To observe the effect of Roux-en-Y gastric bypass (RYGB) on serum lipopolysaccharide (LPS) and cecal flora in type 2 diabetic rats. Methods A total of 10 Sprague-Dawley (SD) male rats were randomly selected and fed basic diet as normal control group (NC group), and another 30 rats were randomly divided into diabetes surgery group (DO group), diabetes control group (DC group) and diabetes sham operation group (DS group). 8 rats were randomly selected from each group and the rest rats were spare. The DO group underwent RYGB surgery. Fasting blood glucose (FPG) and fasting insulin (Fins) levels were measured before and 1st, 2nd, 4th, 8th, 12th week after surgery; Peripheral blood LPS levels were measured before surgery and at 4, 8, 12 weeks after surgery; The cecal contents were taken 12 weeks after surgery to compare the structure and relative abundance of cecal flora. Results DO group: FPG decreased from (9.10±0.88) mmol/L to (5.70±0.91) mmol/L and (5.80±0.83) mmoL/L (P=0.000) at 2 and 4 weeks postoperatively, and to (6.04±0.91) mmol/L and (5.89±1.09) mmoL/L at 8 and 12 weeks postoperatively (P=0.000); Fins began to decline 4 weeks after surgery and decreased to (6.36±0.73) mU/L(P=0.030) and (6.34±0.63) mU/L (P=0.027) at 8 and 12 weeks after operation. Serum LPS decreased from (44.35±2.41) ng/L to (38.42±2.90) ng/L (P=0.000) 4 weeks after operation, and decreased to (32.32±1.45) ng/L and (32.19±1.24) ng/L (P=0.000) at 8 and 12 weeks after operation. The V4 region of the 16S rRNA of cecal contents in type 2 diabetic rats was sequenced by Illumina Hiseq sequencing platform 12 weeks after surgery. The relative abundance of Bifidobacterium in the DO group was (1.59±0.29)% (P=0.011). Conclusion Hypoglycemic effects after RYGB may be associated with improvement of LPS levels and regulation of cecal flora structure. Key words: Roux-en-Y gastric bypass; Type 2 diabetes; Lipopolysaccharide; Cecal flora