Selenium-enriched exopolysaccharides improve skeletal muscle glucose uptake of diabetic KKAy mice via AMPK pathway

Selenium-enriched exopolysaccharides (EPS) produced by Enterobacter cloacae Z0206 have been proven to possess effect on reducing blood glucose level in diabetic mice. To investigate the specific mechanism, we studied the effects of oral supply with EPS on skeletal muscle glucose transportation and consumption in high-fat-diet-induced diabetic KKAy mice. We found that EPS supplementation increased expressions of glucose transporter 4 (Glut4), hexokinase 2 (hk2), phosphorylation of AMP-activated kinase subunit alpha 2 (pAMPK alpha 2), and peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1 alpha), and increased expression of characteristic protein of oxidative fibers such as troponin I and cytochrome c (Cytc). Furthermore, we found that EPS increased glucose uptake and expressions of pAMPK alpha 2 and PGC-1 alpha in palmitic acid (PA)-induced C2C12 cells. However, while EPS inhibited AMPK alpha 2 with interference RNA (iRNA), effects of EPS on the improvement of glucose uptake diminished. These results indicated that EPS may improve skeletal muscle glucose uptake of diabetic KKAy mice through AMPK alpha 2-PGC-1 alpha pathway.