Skeletal muscle macrophage ablation in mice

Area of Science:

• Immunology
• Skeletal Muscle Physiology
• Inflammation Research

Background:

• Macrophages play critical roles in skeletal muscle function and disease.
• Systemic macrophage depletion confounds studies of muscle-specific macrophage effects.
• Targeted depletion methods are needed to isolate muscle macrophage functions.

Purpose of the Study:

• To evaluate two murine intramuscular macrophage depletion methods.
• To assess their efficacy and impact on local inflammation.
• To identify a reliable technique for studying muscle macrophages.

Main Methods:

• Adult C57BL/6 and MaFIA mice were used.
• Intramuscular injections of clodronate liposomes or AP20187 were administered.
• Vehicle controls were injected contralaterally.

Main Results:

• AP20187 treatment in MaFIA mice depleted macrophages but increased neutrophil infiltration.
• Clodronate liposomes effectively depleted macrophages without increasing CD45 intermediate cells.
• Intramuscular clodronate demonstrated selective macrophage depletion.

Conclusions:

• Intramuscular clodronate is a selective and effective method for depleting skeletal muscle macrophages.
• This technique avoids the acute inflammation associated with AP20187 in MaFIA mice.
• It provides a valuable tool for investigating macrophage roles in skeletal muscle.