Fig. 1

NEDD4-1 expression during skeletal muscle regeneration. A Nedd4-1 expression during skeletal muscle regeneration at different days post injury (dpi) with BaCl₂ (1.2% w/v). Upper panels show H&E staining of TA cryo-sections. Degenerating myofibers together with abundant mononuclear cells were observed at 1–3 dpi, while muscle cytoarchitecture was progressively recovered by 30 dpi. Scale bar = 100 μm. Lower panels show representative immunofluorescence of TA cryo-sections, marked with anti-NEDD4-1 (green), LAMININ (red), and DAPI for nuclear staining (blue). Regenerating myofibers exhibit centrally located nuclei. NEDD4-1 expression peaked at 3–7 dpi and decreased by 30 dpi at levels comparable to uninjured muscle. Arrowheads indicate interstitial cells; arrows indicate Nedd4(+) cells closely associated with myofiber’s basal lamina. Scale bar = 20 μm. B Double immunofluorescence for NEDD4-1 and MYOD (left panel) and NEDD4-1 and MYOGENIN (right panel) at 3 and 5 dpi. Arrowheads indicate non-myogenic NEDD4-1(+) cells; arrows indicate myogenic cells co-expressing MYOD or MYOGENIN and NEDD4-1. DAPI was used for nuclear staining (blue). Scale bar = 20 μm