Salidroside ameliorates insulin resistance through activation of a mitochondria-associated AMPK/PI3K/Akt/GSK3[beta] pathway

Background and Purpose Recent reports have suggested that salidroside could protect cardiomyocytes from oxidative injury and stimulate glucose uptake in skeletal muscle cells by activating AMP-activated protein kinase (AMPK). The aim of this study was to evaluate the therapeutic effects of salidroside on diabetic mice and to explore the underlying mechanisms. Experimental Approach The therapeutic effects of salidroside on type 2 diabetes were investigated. Increasing doses of salidroside (25, 50 and 100mg·kg-1·day-1) were administered p.o. to db/db mice for 8 weeks. Biochemical analysis and histopathological examinations were conducted to evaluate the therapeutic effects of salidroside. Primary cultured mouse hepatocytes were used to further explore the underlying mechanisms in vitro. Key Results Salidroside dramatically reduced blood glucose and serum insulin levels and alleviated insulin resistance. Hypolipidaemic effects and amelioration of liver steatosis were observed after salidroside administration. In vitro, salidroside dose-dependently induced an increase in the phosphorylations of AMPK and PI3K/Akt, as well as glycogen synthase kinase 3[beta] (GSK3[beta]) in hepatocytes. Furthermore, salidroside-stimulated AMPK activation was found to suppress the expression of PEPCK and glucose-6-phosphatase. Salidroside-induced AMPK activation also resulted in phosphorylation of acetyl CoA carboxylase, which can reduce lipid accumulation in peripheral tissues. In isolated mitochondria, salidroside inhibited respiratory chain complex I and disturbed oxidation/phosphorylation coupling and moderately depolarized the mitochondrial membrane potential, resulting in a transient increase in the AMP/ATP ratio. Conclusions and Implications Salidroside exerts an antidiabetic effect by improving the cellular metabolic flux through the activation of a mitochondria-related AMPK/PI3K/Akt/GSK3[beta] pathway