Fig. 3
Autografted and allografted muscles: morphology and osteopontin expression. Cryosections of EDL muscle grafts at 5 (a, b) or 3 (c, d) days post-surgery. a H&E-stained sections. Arrows indicate regenerating fibres (small fibres with centrally located nuclei). b Sections stained with anti-MyHCemb (green), anti-laminin (red) and DAPI, as used for quantitation of regenerating fibres. c Sections stained with anti-osteopontin (red), anti-desmin (myoblasts; green) and DAPI. In wild-type (WT) EDL muscle grafted into a wild-type host, anti-osteopontin stained both myoblasts (yellow) and non-myoblast mononuclear cells (red). In osteopontin-null (KO) muscle grafted into an osteopontin-null host, no osteopontin was detected. In allografted osteopontin-null muscle in a wild-type host, osteopontin was only detected in non-myoblast mononuclear cells. In allografted wild-type muscle in an osteopontin-null host, osteopontin was only detected in myoblasts. Arrows and arrowheads indicate myoblasts and non-myoblast mononuclear cells, respectively. d Sections stained with anti-osteopontin (red), anti-F4/80 (macrophages; green) and DAPI. In autografted wild-type muscle, anti-osteopontin stained macrophages (*; yellow) and some additional structures (arrows; red). In autografted osteopontin-null muscle, no osteopontin was detected. In allografted osteopontin-null muscle in a wild-type host, osteopontin was only observed in macrophages (*; yellow). In allografted wild-type muscle in an osteopontin-null host, weak osteopontin staining was observed in some non-macrophage structures (arrows), but not in macrophages (†; green). Bars = 50 μm