CCR2 and Duchenne muscular dystrophy: By using the DMD mouse model, ColI-GFP/mdx5cv mice, and the impaired acute skeletal muscle injury repair model, ColI-GFP/Ccr2-/- mice, our present study shows that myofibroblasts with co-expression of collagen I and α-SMA are present in the fibrotic skeletal muscles, but their α-SMA expression is not detectable by immunostaining.