Macrophage polarization is skewed in OPN^−/−mdx muscles. Quantification of macrophage subpopulations from MACS-sorted F4/80⁺ macrophages isolated from OPN^+/+mdx and OPN^−/−mdx muscles. Plots depict mean values of pooled data from 4-wk-old (top) and 8-wk-old (bottom) mice, assessed as described in Fig. 3. Vertical lines represent standard errors. Animal numbers are indicated on each bar of the graph. Statistical significance determined by Student’s t test. P-values are indicated.