Whole body hyperthermia improves obesity-induced insulin resistance in diabetic mice

Aim: In this study, we examined the efficacy of whole body hyperthermia (WBH) on obesity-induced insulin resistance in diabetic mice.Methods: Male db/db mice were treated with WBH 3 times per week for 12 weeks. The rectal temperature of mice reached 38.0°C 5 min after heating, and was kept at 38.0°C for 30 min. At the end of each week, tail snip glucose levels were determined under fasting conditions. The GLUT-4 gene expression of muscle tissue was analyzed by real-time PCR.Results: (1) WBH-treated db/db mice showed a significant decrease in fasting blood glucose level as compared with untreated db/db mice (p < 0.01). (2) Plasma insulin levels in untreated db/db mice at the age of 10 weeks were significantly increased compared with those of db/+ mice (p < 0.0001). On the other hand, the reduction (31%) in insulin levels in WBH-treated mice indicated improved insulin sensitivity. (3) The ability of WBH to increase insulin sensitivity was further established in glucose tolerance tests and insulin tolerance ...