Thyme honey reduced hyperglycemia in male rats subjected to chronic unpredictable mild stress: Possible involvement of GLUT4 protein and circulating irisin.

Abstract

Objective: Chronic stress is a common and fundamental problem in human life all over the world which threatens the health. Stress-induced metabolic disorders are attenuated by natural honey feeding. So, we examined protective impact of thyme honey in the regulation of blood glucose via measuring the expression level of muscle GLUT4 protein in chronic unpredictable mild stressed (CUMS) male rats.

Materials and methods: Six groups of adult male Wistar rats were designed in this study; control group that received water; unstressed groups that were treated with honey (0.2 and 2 g/kg/day) for 38 days; stressed group that received CUMS for 4 weeks; treated stressed groups that were gavaged by honey (0.2 and 2 g/kg/day) for 38 days (from 10 days before induction of stress until the end of stress period). A day after the experiment period (39^th day), in non-fasting status, rats were sacrificed to measure glucose, insulin, irisin, lipid profile at serum level and GLUT4 protein content in muscle tissue via western blotting method.

Results: Honey reduced hyperglycemia induced by CUMS, significantly increased serum irisin and non-significantly increased high-density lipoprotein cholesterol (HDL-c) which were decreased by CUMS, but did not affect other serum lipids and insulin. CUMS down-regulated GLUT4 protein level. Honey feeding (2 g/kg) in stressed rats interestingly increased level of GLUT4 protein and maintained it at a normal level.

Conclusion: Together, it may be concluded that honey administration protects glycemic control system from chronic stress-induced dysregulation via an increase in production of irisin and maintaining the GLUT4 protein levels.