Background: Ecdysteroids are polyhydroxylated steroids present in invertebrates and plants. 20-Hydroxyecdysone (20E) is the most common and the main biologically active compound of ecdysteroids. Previous studies have demonstrated anabolic and metabolic effects of 20E in mammals. However, it is unknown whether 20E has a positive effect on all aspects of cardiometabolic syndrome. The aims of this study were to investigate the favorable effect and possible underlying mechanisms of 20E in a rat model of cardiometabolic syndrome (CMS) induced by a high-calorie diet combined with female sex hormone deprivation.
Methods: 20E (5 mg/kg, 10 mg/kg, or 20 mg/kg) or pioglitazone (PIO) (10 mg/kg) was intragastrically administered to sham-operated Sprague-Dawley female rats and ovariectomized rats fed a high-fat-high-fructose diet (OHFFD) for 8 weeks. The phenotypic characteristics of CMS, including central adiposity, blood pressure, serum lipid profile, glucose tolerance, insulin action on skeletal muscle glucose transport activity and hepatic protein expression, were determined.
Results: Some CMS characteristics were improved by 20E treatment. Rats treated with 20E had lower body weight, abdominal fat accumulation than rats treated with vehicle control without changes in total caloric intake and fat-free mass. OHFFD rats exhibited high blood pressure, but 20E-treated rats maintained normal blood pressure with a lower level of low-density lipoprotein (LDL)-cholesterol. Although 20E showed no positive effect on inducing insulin-mediated glucose transport in the skeletal muscle of OHFFD rats, 20E improved whole body glucose homeostasis. Analysis of protein expression in livers from 20E-treated rats revealed significantly increased expression of pAkt Ser473, pFOXO1 Ser256, pAMPKα Thr172, and FGF21.
Conclusion: 20E treatment can alleviate cardiometabolic disorder caused by a high-fat-high-fructose diet and female sex hormone deprivation. In particular, 20E helps improve whole body insulin sensitivity in OHFFD rats, and the mechanisms that underlie this favorable effect are potentially mediated by the activation of AMPK and FGF21. The present study indicates that 20E could be an alternative therapeutic option for the prevention and alleviation of cardiometabolic syndrome.
Keywords: 20-hydroxyecdysone; Cardiometabolic syndrome; Glucose metabolism; High-fat high-fructose diet; Ovariectomy.