Interleukin-6 mediates exercise-induced increase in insulin sensitivity in mice

Area of Science:

• Exercise Physiology
• Immunometabolism
• Skeletal Muscle Biology

Background:

• Interleukin-6 (IL-6) is released by skeletal muscle during exercise.
• IL-6's role in exercise-induced glucose uptake and insulin sensitivity is not fully understood.
• Understanding IL-6's function is crucial for metabolic health research.

Purpose of the Study:

• To investigate the acute and long-term effects of IL-6 on exercise-induced glucose uptake in skeletal muscle.
• To examine the impact of IL-6 on insulin sensitivity in mice on a high-fat diet.
• To determine the contribution of endogenous IL-6 to exercise-mediated metabolic improvements.

Main Methods:

• Utilized IL-6-deficient (IL-6(-/-)) and wild-type mice.
• Measured acute glucose uptake using a tracer technique after exercise.
• Assessed long-term insulin sensitivity, RBP-4 levels, and body composition in mice on a high-fat diet with/without running wheels.

Main Results:

• No difference in serum glucose disappearance post-exercise between genotypes, but IL-6(-/-) mice showed lower muscle glucose uptake.
• High-fat diet reduced insulin sensitivity and increased RBP-4 in sedentary mice of both genotypes.
• Exercise protected wild-type mice against high-fat diet effects, while IL-6(-/-) mice exhibited diminished benefits, with impaired insulin sensitivity and elevated RBP-4.

Conclusions:

• Endogenous IL-6 plays a significant role in mediating exercise-induced improvements in insulin sensitivity.
• IL-6 has a minor role in acute exercise-induced glucose uptake in skeletal muscle.
• IL-6 is essential for maximizing the metabolic benefits of exercise, particularly concerning insulin sensitivity.