Fig. 4

C/EBPβ is required for restoring the muscle stem cell pool after acute injury. a Experimental design. C/EBPβ^fl/fl Pax7^+/+ (wild-type) and conditional null C/EBPβ^−/−Pax7^CreER−/+ (C/EBPβ^−/−) mice were injected daily with tamoxifen for 5 days. One week after the last injection, the left tibialis anterior (TA) muscle was injured by intramuscular injection of 50 μl of 1.2% BaCl₂. The muscle was analyzed at 0, 4, 7, and 42 days post injury (dpi). b Cross-sections of uninjured TA were immunostained for Pax7 (red), C/EBPβ (green), and laminin (white). Nuclei were counterstained with DAPI (blue). Representative pictures are shown. Scale bar, 20 μm. c Excision efficiency in Cre⁺ satellite cells represented by the percentage of C/EBPβ⁺ nuclei among total Pax7⁺ cells in uninjured muscle (n = 3). d Cross-sections of injured TA 0, 4, 7, and 42 dpi were immunostained for Pax7 (red) and counterstained with DAPI (blue). Representative pictures are shown. Scale bar, 20 μm. e Pax7⁺ cells per area (mm²) at 0, 4, and 7 dpi (n ≥ 3 mouse pairs). f Pax7⁺ cells per area (mm²) at 42 dpi (n = 4 mouse pairs). For all panels, data is represented as mean ± SEM, *p <0.05, **p < 0.01, n.s. not significant