Inhibition of MMP-9 promotes M2 macrophage phenotype in skeletal muscle of mdx mice.

<p>GA muscle of 8-week old mdx;Mmp9^+/+ and mdx;Mmp9^+/− mice were isolated and processed for FACS analysis for M1 and M2 macrophages in the F4/80⁺ population after gating out CD45 and Sca1 cells. (<b>A</b>) FACS dot plots displaying the percentage of CD11c⁺ M1-macrophages (upper left quadrant). (<b>B</b>) Representative dot plots for the percentage of CD206⁺ M2 macrophages (lower right quadrant). (<b>C</b>) Quantification of relative proportion of M1 and M2 macrophages by FACS technique in GA muscle of mdx;Mmp9^+/+ and mdx;Mmp9^+/− mice. (<b>D</b>) Fold change in relative mRNA levels of CD163, TNF-α, IL-1β, IL-6, IFN-γ, Il-10, and IL-4 measured by QRT-PCR assay in GA muscle of 8-week old mdx;Mmp9^+/+ and mdx;Mmp9^+/− mice. N = 3 or 4 in each group. Error bars represent SD. *p<0.05, values significantly different from mdx;Mmp9^+/+ mice.