Effects and mechanisms of Roux-en-Y gastric bypass and sleeve gastrectomy on metabolism in hyperuricemic rat model

Objective To investigate the effects of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) on metabolism of serum uric acid, blood glucose and lipid profiles in hyperuricemic rat model, and by observing the alteration of serum LPS, IL-6, TNF-α and XO to explore the related mechanism. Methods Forty Wistar rats were randomly divided into hyperuricemic model group and control group. The model group were administered high purine food and orally intragastrical adenine and potassium oxonate to establish the hyperuricemic rat model while the control group was fed on standard food. Three weeks later, the model group was assigned to three subgroups: RYGB, SG, Sham. Then different operational procedures were performed. Body weight and amounts of food intake were recorded before the surgery and 2, 4, 6, 8 weeks following surgical operations. Pre- and postsurgical serum uric acid, BUN and creatinine, fasting plasm glucose, fasting insulin concentration, HOMA-IR, triglyceride and total cholesterol were assessed. Serum LPS, IL-6, TNF-α level and concentration of XO were measured. Results Preoperatively, compared with control group, serum uric acid, urea nitrogen, creatinine level of model group significantly increased, indicating that the established hyperuricemic rat model by high purine food intake and oral intragastrical administration of adenine and potassium oxonate was successful. The biochemical index of fasting blood glucose and lipid profiles and inflammatrory markers LPS, IL-6, TNF-α in model groups was much higher than that in control group (P<0.001). After surgery, compared with Sham group, body weight, amount of food intake, serum uric acid serum urea nitrogen and creatinine levels and fasting plasm glucose, serum insulin, insulin resistance index(HOMA-IR score), serum triglyceride and total cholesterol levels were significantly decreased (P<0.01). RYGB and SG surgery lowered serum LPS, IL-6, TNF-α and XO concentration compared with Sham group (P<0.01). Conclusions RYGB and SG surgery significantly reduced serum uric acid level and improved the imbalance of metabolism of glucose and lipid profiles of hyperuricemic rat. Mechanically, RYGB and SG surgery might reduce serum uric acid by reducing fat mass, relieving inflammation and insulin resistance as well as regulating the expression of XO. Key words: Roux-en-Y gastric bypass surgery; Sleeve gastrectomy; Hyperuricemic rat mdoel; Uric acid; Glycolipid metabolism