Effects of Roux-en-Y gastric bypass on hepatic lipid metabolism in obese diabetic rats

Abstract

Objective To explore the effects of Roux-en-Y gastric bypass (RYGB) on hepatic autophagy in obese diabetic rats. Methods Sprague-Dawley diabetes rats were randomly divided into three groups: diabetic group(n=8), diabetic sham RYGB group (n=8) and diabetic RYGB group (n=8). Hyperinsulinemic-euglycemic clamps with tracer infusion were completed to assess insulin sensitivity (IS). Triglyceride (TG) levels in liver tissue were tested. The protein expression levels of P62 (sequestosome 1)and the conversion of LC3(microtubule-associatedprotein 1 light chain 3) in liver were detected by Western blot. The concentration of glucagon-like peptide-1 (GLP-1) in plasma was detected by ELISA and the correlation between GLP-1 and autophagy was analyzed in 2 weeks after operation. Results In comparison with diabetic and diabetic sham RYGB groups, IS increased by 63% (F=10.87, P<0.01) and TG content decreased by 91% (F=146.3, P<0.01) in the liver in RYGB group .In RYGB group, the conversion of LC3-Ⅰ to LC3-Ⅱ raised(F=17.01, P<0.01), the protein expression of P62 decreased(F=19.77, P<0.01) and the concentration of GLP-1 in plasma increased by 90%(F=112.8, P<0.01). The marked increase of autophagy in liver after RYGB correlated with the plasma GLP-1 level (r2=0.66, P=0.014 3). Conclusions RYGB reduces hepatic lipid toxicity and improves lipid metabolism disorder by increasing autophagy, increased GLP-1 secretion after RYGB may be one of the reasons for activating autophagy. Key words: Diabetes mellitus, type 2; Anastomosis, Roux-en-Y; Lipid metabolism disorders