Objective      To investigate the effects of Roux-en-Y gastric bypass (RYGB) on aquaporin-9 (AQP9) expression in the liver of rats with type 2 diabetes mellitus (T2DM)

and to explore the mechanism for RYGB ameliorating T2DM.       Methods        Forty SD rats randomly chosen from 50 were divided into three groups: diabetes group (group B

n=10)

diabetes

sham operation group (group C

n=10)

and diabetes operation group (group D

n=10). The left 10 rats were used as normal control group (group A). The levels of fasting blood glucose (FBG)

insulin and glucagon-like peptide 1 (GLP-1) were measured before operation and at 5

10

15 and 20 d after operation. All the rats were sacrificed at 20 d after operation and the expression of AQP9 in rat livers was determined by immunofluorescence assay and Western blotting.       Results        As for the group D

the level of FBG decreased from (23.4±1.6) mmol/L (before operation) to (8.7±0.8) mmol/L and (7.8±0.8) mmol/L at 5 d and 20 d after operation

respectively. The level of fasting insulin did not change significantly. The level of fasting GLP-1 increased from (7.7±0.3) pmol/L (before operation) to (16.8±0.9) pmol/L and (20.3±0.7) pmol/L at 5 d and 20 d after operation

respectively. The relative expression level of AQP9 was significantly lower in the group D (0.21±0.02) than in the group B (0.54±0.11) and group C (0.58±0.09) after operation (

P

0.05).        Conclusion        RYGB can significantly reduce the levels of FBG and AQP9 expression in the liver of rats with T2DM.