Fig. 1

Reduced number of myonuclei derived from muscle satellite cells in exercised HeyL-KO mice. (A) Number of Pax7⁺ cells per 100 myofibers in sections of soleus or plantaris muscles from male non-exercised WT (HeyL^+/+, n = 5) or KO (HeyL^−/−, n = 5). (B) Experimental design for analyzing the effect of a 2-week wheel running exercise on the number of MuSC-derived myonuclei. Littermate control (WT: HeyL^+/+) or HeyL-KO (KO: HeyL^−/−) mice were randomly separated into two groups; home cage (-Ex: non-exercise group) or wheel running cage (+ Ex: exercise group). EdU was administrated through osmotic pumps during 2-week running. (C) Number of wheel rotations during 2 weeks in WT (n = 8) or KO (n = 7) mice. (D) Immunostaining of dystrophin (green) and EdU (white) in soleus muscle 2 weeks after wheel running. Arrowheads indicate EdU⁺ myonuclei. Scale bar, 25 μm. (E) Number of EdU⁺ myonuclei per 100 myofibers in sections of soleus or plantaris muscle from exercised WT (n = 8) or KO (n = 7) mice. (F) Immunostaining of Pax7 (red), Laminin α2 (LNα2, green), and EdU (white) in soleus muscle 2 weeks after wheel running. Arrows indicate Pax7⁺EdU⁺ cells. Red arrows or arrowheads indicate Pax7⁺EdU⁺ cells or EdU⁺ myonuclei, respectively. White arrow indicates Pax7⁺EdU⁻ cell. Scale bar, 25 μm. (G) Number of Pax7⁺EdU⁺ cells per 100 myofibers in sections of soleus or plantaris muscle from exercised WT (n = 8) or KO (n = 6) mice