Figure 2.

Localization of Vitamin D Receptor (VDR) in regenerating mouse and human skeletal muscle. (A,B) Muscle regeneration was induced in the mouse tibialis anterior muscle by injecting BaCl₂ (1.2%), and the tibialis anterior muscle was harvested 7 days following injury. Immunohistochemical analysis revealed regenerating fibers with centrally-located myonuclei (A, DAPI) show strong positive VDR expression (B, red puncta) in myonuclei. (C,D) A vastus lateralis biopsy was obtained from a human research participant 7 days after severe thermal injury, which we have shown to induce significant skeletal muscle regeneration (Fry et al. 2016). Myonuclear localization of VDR (D, red puncta) is observed, with the strongest VDR intensity present within myonuclei (C, DAPI) of small, regenerating fibers. In all images, laminin (green) denotes the fiber border. In images A and C, DAPI (blue) denotes nuclei. In images B and D, DAPI is omitted to allow visualization of VDR staining within nuclei. Scale bar = 100 μm.