Figure 4.

Representative transverse sections from 12 mice (1-12), whose right TA muscles were grafted with ~ 400 satellite cells derived from old mdx × Myf5^nlacZ/+ mice (donor cells pooled from 2 × 15 month old males) (A, A′, B, B′). Of the same 12 mice, 7 left TA muscles (1-7) were engrafted with ~ 400 old Myf5^nlacZ/+ (15 month old male, n = 1) (D, D′, E, E′) and the remaining 5 left TA (8-12) muscles were engrafted with ~ 400 young mdx × Myf5^nlacZ/+ (3 month old male, n = 1) (G, G′, H, H′) mice. Sections were either stained with X-gal (A A′, D, D′,G, G′) or immunostained for neonatal MyHC (nMyHC, green) and dystrophin (dys, red) (B, B′, E, E′, H, H′). Boxed area in A,B, D, E, G and H shown at higher magnification in A', B', D', E', G', H'. Scale bar = 100 μm. (C, F, I) depict numbers of myofibers with at least one X-gal + ve nucleus (blue, of donor origin) and neonatal MyHC (green) (i.e. myofibers of donor origin and newly regenerated). (F, I) Where Myf5nlacZ/+ were transplanted, dystrophin was also quantified. Nuclei in B, E, H and B′, E′, H′ were counterstained with DAPI.