Figure 2. AMPKα1 in macrophages is required for glucocorticoid‐dependent resolution of inflammation during cardiotoxin induced skeletal muscle damage.

• A–C
  After cardiotoxin injection to damage the muscle, AMPKα1^fl/fl (WT) and LysM‐α1^−/− mice were treated with a single dose of Dexamethasone (Dex) intra‐peritoneal (i.p.) (0.1 mg/kg) at day 3 (D3) and Tibialis Anterior (TA) muscles were harvested at day 8 (D8) and 14 (D14) after injury. (A) Representative embryonic myosin heavy chain (EmbMHC) immunostaining on whole TA muscle section at D8 and D14 after injury. (B) Quantification of (A), results are expressed as percentage of positive myofibers expressing the EmbMHC on the whole muscle section. (C) Muscle mass at D14 after injury.
• D, E
  TA muscle from WT and AMPKα1^−/− (D) or LysM‐α1^−/− (E) mice was damaged with cardiotoxin and Dex (or vehicle) was i.p. injected around 60 h after injury (~ 2.5 days) prior CD45^pos cells were sorted with magnetic beads 15 h later (day 3). (D) CD45^pos CD64^pos Ly6C^pos, Ly6C^int and Ly6C^neg macrophage subsets were cultured with dead fluorescently labeled myoblasts for 6 h. Phagocytosis was evaluated by flow cytometry and expressed as the GeoMean fluorescence Intensity of the phagocyting cells. (E) The proportion of macrophages (CD64^pos) expressing anti‐inflammatory markers was assessed by flow cytometry.
• F
  Macrophage polarization was determined by immunofluorescence in vehicle, DAMPs and DAMPs + Dex treated WT and AMPKα1^−/− BMDMs.

Data information: results are displayed with box and whiskers in which the central band represents the median (B, C, D, E) or means ± SEM (F). N = 7–12 muscles (B, C), 5–6 biological replicates (D), 4–12 muscles (E) and 4–5 biological replicates (F). *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001 using ANOVA (B‐F) tests. Bars = 500 μm (A), 25 μm (F).