Figure 1.

Overview of tissue histology during mouse skeletal muscle regeneration. (A) A time course of histological changes in regenerating skeletal muscle. H&E staining of uninjured TA muscles and regenerating TA muscles at 5, 10 and 30 days after intramuscular cardiotoxin injection. Regenerating muscles are reduced to mostly mononuclear cells at day 5, but are able to re-establish multinucleated myofibres by day 10. Notably, the nuclei of uninjured myofibres are located at the periphery, whereas those of regenerating muscle fibres are centrally located. Scale bar, 50 μm. (B) Longitudinal view of whole tissue preparations of uninjured (left) and regenerating (right) skeletal muscle. Immunostaining for the extracellular matrix protein laminin (green) labels the basal lamina surrounding myofibres and capillaries. In regenerating conditions, the proliferation of satellite cells can be observed by the increase in the number of Pax7 (red) expressing cells (arrows). DAPI staining of nuclei (blue) reveals accessory cells in the satellite cell niche. Scale bar, 50 μm. H&E, haematoxylin and eosin; TA, tibialis anterior.