Mechanism of Roux-en-Y gastric bypass and gastric banding on type 2 diabetes

Abstract

Objective To clarify mechanism of Roux-en-Y gastric bypass (RYGB) and gastric banding on diabetes induced by STZ injection. Methods 40 rats with STZ induced diabetes were randomly allocated into Roux-en-Y gastric bypass (RYGB) group (group RYGB, n=10), gastric banding group (group GB, n=10 ), diet control group (group F, n=10), control group (group C,n= 10). The fasting blood glucose, the fasting insulin IGF-1, the fasting Plasma leptin, the fasting plasma insulin level, the weight and the food-intake, the operation time, the death rate were measured and recored before and after operation on 1st , 2nd, 3 rd ,4th, 8th and 16 th week postoperatively. Results The fasting blood glucose of the group of gastric banding(GB) descended to (12.6±3.7) mmol/L, the fasting plasma insulin rose to (58.7±9.2) mIU/L, the fasting plasma leptin descended to (14.6±3.3) pg/ml, the weight was (212.6±15.1) g.There were significant differences between before and after operation on 16 th week(P<0.01). The fasting blood glucose of the group of Roux-en-Y (RYBG) descended to 8.8±4.9 mmol/L in the sixteenth week, the fasting insulin IGF-1 rose to (148.6±7.3) ng/L, the fasting plasma insulin rose to (14.1±3.5) pg/ml, the fasting plasma leptin descended to 14.1±3.5 pg/ml, the weight was (200±15.1) g. There were significant differences between before and after operation 16 th week (P<0.01). There were significant differences of the fasting plasma insulin and the the fasting plasma leptin between group F and group C during the 3 rd to 4th week after operation (P<0.05). Compared the weight of the group F and the group C on the third week of operation, there were significant differences (P<0.05), and there were no significant differences in other time. The fasting blood glucose of the group F and the group C had no sig-nificant differences between before and after operation.(P<0.05). Conclusions The fasting blood glucose and the fasting insulin level of the group F improve more than of the group GB at the same time. The plasma insulin and the plasma leptin of the two groups all work in glucose control. The diet control and the modification of the plasma insulin and the plasma leptin all play a major role in the gastric banding mechanism, and the IGF-1 may work in the descending the blood glucose after the operation of Roux-en-Y. In the operation time and die rate, the group of F surpass the group of GB. Key words: Roux-en-Y gastric bypass; Gastric banding; Diabetes mellitus type 2