Fig. 4

Satellite cell content and muscle regeneration. a Pax7 and Ki67 double staining of the quadriceps muscle sections. Arrowheads represent Pax7-positive and Ki67-negative quiescent satellite cells, and arrows represent double-positive (Pax7+/Ki67+) proliferated satellite cells. b The numbers of Pax7+/Ki67+ cells/field and Pax7+/Ki67− cells/field (×400 magnification) in wild-type and dKO mice treated with rat IgG or MR16-1 were compared. The greater number of both activated and quiescent satellite cells was found in dKO mice compared with wild-type mice. While the number of Pax7+/Ki67+ satellite cells was not different, Pax7+/Ki67− satellite cells were significantly increased in MR16-1-treated dKO mice (P < 0.05). c A representative image of eMyHC-positive regenerating muscle fibers in dKO mice treated with rat IgG or MR16-1. d The percentage of eMyHC-positive area per total area. e The number of eMyHC-positive regenerating muscle fibers per field (× 200 magnification). f The percentage of average eMyHC-positive muscle fiber size. g Gene expression levels of myh3, normalized by Lbr, was expressed as fold increase of wild-type mice (n = 3–4 per group). h The percentage of number of myonuclei per fiber. *P < 0.05, **P < 0.01