Fig. 1

Punch biopsy removes all skeletal muscle tissue components. A A biopsy punch was used to create a local injury (diameter, 2 mm) through the GM (muscle perimeter outlined by broken yellow line). B Microvascular perfusion was disrupted at the site of the injury at 1 dpi. Intravascular injection of fluorescent dextran showed the empty biopsy site in addition to a small unperfused region downstream of the injury. C Representative Sirius red staining of collagen at 1 dpi highlighting deposition of a provisional matrix in the wound; yellow asterisk indicates residual gap. D Stitched tile scan of immunostained whole mount GM at 1 dpi showing masses of inflammatory cells (CD45⁺, red) and fibroblasts (PDGFRα⁺, magenta) invading the provisional matrix; capillaries (CD31⁺, green) retain their orientation parallel to uninjured myofibers. E Higher magnification at wound edge within broken yellow squares in D