Fig. 4

Small-diameter regenerating muscle fibers (eMHC+) in Col6a1KO mice were matured by COL6 supplementation. a Sectional images of TA muscles 1 week after medium injection (Col6a1KO) or cell transplantation. Yellow arrows indicate multi nuclei eMHC+ fibers. b Number of eMHC-positive fibers 1 week after the transplantation. c CSA per single eMHC+ TA muscle fiber 1 week after the transplantation. d Number of nuclei in eMHC+ TA muscle fibers 1 week after the transplantation. e % of eMHC+ TA muscle fibers with more than three nuclei 1 week after the transplantation. f Sectional images of whole TA muscle 1 week after medium injection (Col6a1KO) or cell transplantation. Two serial sections were stained. g Western blots for COL6A1 protein expression in pMSC-, iMSC-, and KO-iMSC-transplanted TA muscle tissue samples of Col6a1KO mice and TA muscle tissue samples of WT mice. GAPDH was used as the control. Data are the mean ± SD. n = 20 (medium; Col6a1KO), n = 10 (iMSCs), and 6 (pMSCs and KO-iMSCs each). *P < 0.05. **P < 0.01