Research Paper Volume 10, Issue 4 pp 747—763

Oxidative stress-mediated senescence in mesenchymal progenitor cells causes the loss of their fibro/adipogenic potential and abrogates myoblast fusion

Figure 5. SASP of PMS-2G11 cells abrogated myotube formation. (A) Immunocytochemical analysis of MHC in skeletal muscle primary cells cultured alone or cocultured with 2G11 or PMS-2G11 cells. Arrowhead: MHC+ myotube. Scale bar: 100 μm. (B) Distribution of multinucleated myotubes of differentiated skeletal muscle primary cells cultured alone or cocultured with 2G11 or PMS-2G11 cells. Upper panel: relative numbers of myotubes containing specified numbers of nuclei. White and red arrowheads: median values of the number of nuclei per myotube, cultured alone and cocultured with 2G11 cells, respectively. Lower panel: plot showing relative cumulative percentages of myotubes, based on the data shown in the upper panel. Black and red lines: myotubes cultured alone and cocultured with 2G11 cells, respectively. (C) Fusion index of differentiated skeletal muscle primary cells, quantified as the percentage of the number of nuclei in myotubes (>2 myonuclei) relative to the total number of nuclei in a field. Data are expressed as means±SE (n=4); **P<0.01. (DF) Quantification of Pax7+ cells (D), MyoD+ cells (E), and myogenin+ cells (F) of skeletal muscle primary cells cultured alone or cocultured with 2G11 or PMS-2G11 cells. Data are expressed as means±SE (n=4).