The effect of aging on glucose metabolism improvement after Roux-en-Y gastric bypass in type 2 diabetes rats

BACKGROUND: This study aimed to investigate the effect of aging on glucose metabolism improvement after Roux-en-Y gastric bypass (RYGB) in rat models with type 2 diabetes mellitus (T2DM). METHODS: Twenty aged Goto-Kakizaki rats were randomly assigned into RYGB-A group and sham RYGB (SR-A) group, and 10 adult Goto-Kakizaki rats also accept RYGB procedures (RYGB-Y). Glucose metabolism, resting energy expenditure (REE), glucagon-like peptide-1 (GLP-1) and total bile acid level were measured. RESULTS: RYGB could significantly improve glucose metabolism in aged diabetic rats. The fasting blood glucose level in the RYGB-A group decreased from 15.8 ± 1.1 mmol/l before surgery to 12.3 ± 1.5 mmol/l 16 weeks after surgery (P < 0.01), and the AUC(OGTT) value decreased from 2603.9 ± 155.4 (mmol/l) min to 2299.9 ± 252.8 (mmol/l) min (P = 0.08). The decrease range of fasting blood glucose in the RYGB-A group was less than that in the RYGB-Y group (20.5% ± 6.5% vs. 40.6% ± 10.6%, P < 0.01), so is the decrease range of AUC(OGTT) value (11.6% ± 14.8% vs. 38.5% ± 8.3%, P < 0.01). Moreover, at the 16th postoperative week, the increase range of REE of the RYGB-A group was lower than that of the RYGB-Y group (15.3% ± 11.1% vs. 29.1% ± 12.1%, P = 0.04). The increased range of bile acid of the RYGB-A group was less than that of the RYGB-Y group (80.2 ± 59.3 % vs.212.3 ± 139.0 %, P < 0.01). The GLP-1 level of the RYGB-A group was less than that of the RYGB-Y group (12.8 ± 3.9 pmol/L vs. 18.7 ± 5.6 pmol/L, P = 0.02). There was no significant difference between the RYGB-A group and the RYGB-Y group in the level of the triiodothyronine level. CONCLUSIONS: RYGB could induce a glucose metabolism improvement in aged diabetic rats, and aging might moderate the effect of RYGB.