Abstract:

Objective To investigate the effects of Roux-en-Y gastric bypass surgery (RYGB) on the insulin resistance of type 2 diabetes and the variation of fatty acid oxidation of skeletal muscle. Methods The variations of body weight, fasting blood glucose, fasting insulin, insulin resistance index, free fatty acid, and fatty acid oxidation rate of skeletal muscle of diabetic GK rats (diabetic group), diabetic GK rats underwent RYGB (RYGB intervention group), and normal wistar rats (control group) were observed. Lead citrate electronic staining was adopted to stain the skeletal muscle of the rats. The variations of micro-structure and mitochondria of the skeletal muscle of 3 groups were observed under the transmission electronic microscope. Results Compared with the diabetic group, the level of serum free fatty acid of the RYGB intervention group tended to decrease; fatty acid oxidation rate of the skeletal muscle increased; and body weight, fasting blood glucose, fasting insulin, and insulin resistance index improved significantly (P<0.05). The fatty acid oxidation rate of the skeletal muscle of RYGB intervention group, diabetic group, and control group were (4.75±1.03)%, (1.9±0.27)%, and (2.67±0.53)%, respectively. The differences of the diabetic group and control group, and the RYGB intervention group and diabetic group were statistically significant (P<0.05). Compared with the control group, the myofilament structure of skeletal muscle of the diabetic group was disorder; soluble cavitations appeared; the number of mitochondria decreased; swelling was obvious; and local degeneration of vesicular necrosis was found. Compared with the diabetic group, the sarcomere arrangement of skeletal muscle and the number of mitochondria of the RYGB intervention group were significantly improved. Conclusion RYGB may relieve the insulin resistance of diabetic rats by decreasing the level of serum free fatty acid and protecting the function of fatty acid oxidation of skeletal muscle.

Key words: insulin resistance, Roux-en-Y gastric bypass surgery, skeletal muscle, fatty acid oxidation, type 2 diabetes