Figure 4From: MYOD mediates skeletal myogenic differentiation of human amniotic fluid stem cells and regeneration of muscle injuryRegeneration of TA muscle injury by MYOD transduced hAFS cells. Left TA muscle of immunodeficient BALB/cSlc-nu mice was injured with cardiotoxin (0.4 nM/mouse), and EGFP positive hAFS cells transduced with EV and MYOD viruses. (a) H&E staining of TA muscles at 7 and 21 days after injection of EV- or MYOD-hAFS cells (black dashed line: injured site). (b) The area of muscle tissue was measured using the i-solution image program at 7 and 21 days after injection (n = 9; three per mouse). The muscle area was significantly increased in the MYOD-hAFS cell-injected group compared to the group injected with EV-hAFS cells or the control (*P <0.0002 and **P <0.002). (c) The size of muscle fibers of MYOD-hAFS cell-transplanted TA muscle was larger than that of CTX only or EV-hAFS cell injected TA muscles. Using the i-solution program, the average size of centrally nucleated myofibers and whole myofibers was calculated (n = 48; 16 per mouse) (*P < .004 and **P <0.03). The percentage of centrally nucleated fibers over total fibers was also calculated (n = 48; 16 per mouse) (*P <0.02). (d) Injected hAFS cells were visualized with eGFP signal (green) and DAPI with confocal microscopy (white dashed line: regenerating muscle fiber). (e) TA muscles injected with CTX only (control), EV- or MYOD-hAFS cells were stained with α-BTX at 21 days after injection. The area of α-BTX binding was measured using the i-solution image program (n = 32; 16 per mouse) (*P <0.03 and **P <0.02) (Scale bar; a = 500 μm, 7 days of c = 10 μm and others = 20 μm). α-BTX, α-bungarotoxin; CTX, cardiotoxin; DAPI, 4',6-diamidino-2-phenylindole; EV, empty vector; hAFS, human amniotic fluid stem; TA, tibialis anterior.Back to article page