(A and B) Representative images of H&E and immunofluorescence staining of muscle sections from Inhba^fl/fl mice (n = 8) and Inhba^fl/fl LysM-Cre mice (n = 8) at 4 dpi. In immunofluorescence staining, sections were stained for anti-mouse eMyHC (red) to indicate regenerating fibers and Hoechst (blue) to indicate nuclei. The boxed areas are magnified (×4) in the panels to the right. H&E staining and corresponding immunofluorescence images represent the same field of view. Scale bars: 100 μm. (C–E) Quantification of regeneration showing the distribution of the CSA of eMyHC⁺ fiber (C), the mean CSA of eMyHC⁺ fibers in an individual mouse (D), and the percentage of regeneration area (calculated as total eMyHC⁺ area/injured area) (E). (F and G) Representative images of H&E and immunofluorescence staining of muscle sections from Inhba^fl/fl mice (n = 8) and Inhba^fl/fl LysM-Cre mice (n = 8) at 4 dpi. In immunofluorescence staining, sections were stained for mIgG (white) to indicate necrotic fibers. H&E staining and corresponding immunofluorescence images represent the same field of view. Scale bars: 50 μm. (H) The density of mIgG⁺ fibers (calculated as the number mIgG⁺ fibers/injured area). (I) Grip strength of the forelimb in Inhba^fl/fl and LysM-Cre Inhba^fl/fl mice at 7 dpi. gf, gram force. (J and K) Photographs of gastrocnemius of the Inhba^fl/fl (J) and LysM-Cre Inhba^fl/fl (K) mice at 14 dpi. Scale bars: 5 mm. (L) Mass of gastrocnemius of Inhba^fl/fl and LysM-Cre Inhba^fl/fl mice at 14 dpi. The P values were calculated using unpaired 2-tailed t test. A P value < 0.05 was considered significant. Data are shown as the mean ± SEM, and symbols represent individual fibers (C) or individual mice (D, E, H, I, and L).