Fig. 3. Promotion of the regeneration observed in the Rrm2b smKO mice.

a H&E staining results of skeletal muscle from the Rrm2b smKO mice. Blue arrows indicate the centronucleated muscle fibers. Asterisk indicates adipose accumulation. Scale bar, 100 μm. b The percentage of centronucleated muscle fibers in the Rrm2b smKO mice. At least 6 photos (200×) from different fields were examined for each mouse. All single fibers were counted to determine whether the myonuclei were centrally located; 8 mice were in each group. c Quantification of the adipose area of the Rrm2b smKO mice. Five-month-old Rrm2b smKO mice showed a significant increase in the adipose area. The adipose area within the muscle fibers of the femoris was quantified with ImageJ software. The ratios were calculated by adipose area versus the whole femoris section, with 5 mice in each group. d Muscle fiber diameter of the femoris in the Rrm2b smKO mice. The diameter of 300 myofibers was measured in the femoris muscle of each mouse; 5 mice were in each group. e Immunostaining results of MuSCs (Pax7-positive) on isolated single myofibers in 3-month-old Rrm2b smKO mice; 15–20 myofibers in each mouse and 3 mice in each group were used. f EBD staining of TA muscle sections at 3, 7, and 14 days after injury. Red fluorescence indicates the damaged myofibers. Green fluorescence indicates immunostaining of laminin. Blue fluorescence indicates staining of DAPI. The mice were 5 months old. The results are presented as the mean ± SD. Statistical analysis of differences between the groups was performed by two-tailed, unpaired t-tests, and the P-values were calculated. Asterisks denote statistically significant changes from the control and are defined as *P < 0.05; **P < 0.01; ***P < 0.001. Scale bar, 100 μm.