Interleukin-6 modifies mRNA expression in mouse skeletal muscle.

Area of Science:

• Exercise physiology
• Molecular biology
• Muscle metabolism

Background:

• Interleukin-6 (IL-6) is a cytokine with known roles in inflammation and immune responses.
• Its specific role in skeletal muscle adaptations to exercise, particularly concerning key metabolic and signaling pathways, requires further elucidation.

Purpose of the Study:

• To investigate the role of IL-6 in exercise-induced changes in peroxisome proliferator-activated receptor gamma coactivator (PGC)-1α and tumor necrosis factor (TNF)-α mRNA expression in skeletal muscle.
• To examine the potential regulation of AMP-activated protein kinase (AMPK) signaling by IL-6 during exercise.

Main Methods:

• Comparison of exercise responses between IL-6 knockout (KO) mice and wildtype (WT) mice.
• Treadmill exercise protocol (1 hour) followed by immediate or 4-hour post-exercise muscle tissue collection (white gastrocnemius and quadriceps).
• Analysis of muscle glycogen concentration, AMPK and Acetyl CoA carboxylase (ACC) phosphorylation, and PGC-1α and TNF-α mRNA levels.

Main Results:

• Exercise reduced muscle glycogen significantly in WT mice, but not in IL-6 KO mice.
• AMPK and ACC phosphorylation increased post-exercise in WT mice, with no change observed in IL-6 KO mice.
• IL-6 influenced PGC-1α mRNA expression and TNF-α mRNA responses to exercise, with distinct patterns observed between WT and IL-6 KO mice.

Conclusions:

• IL-6 plays a significant role in modulating exercise-induced changes in skeletal muscle.
• The findings highlight IL-6's involvement in regulating glycogen utilization, AMPK signaling pathways, and TNF-α mRNA expression in response to physical activity.