Fig. 2.

Exercise promotes SC contribution to myofibers in a load-dependent manner. aPax7^CreERT2 mice were crossed with Rosa^mTmG mice to genetically trace SC fusion to myofibers. Upon tamoxifen treatment SCs will express mGFP. mGFP⁺ myofibers indicate fusion of SCs. b A cryosection from a vehicle-treated mouse (negative control sample) was used to determine the threshold and to ensure the elimination of autofluorescence. c Representative cross-sections of soleus (SOL), plantaris (PLT), gastrocnemius (GAS), tibialis anterior (TA), and extensor digitorum longus (EDL) muscle showing GFP⁺ myofibers to which SCs contributed. d Quantification of GFP⁺ myofibers. Statistics, one-way ANOVA test with Tukey correction for multiple comparisons (*p < 0.05; **p < 0.01; ***p < 0.001). Each dot represents a single mouse. Bar graphs represent mean ± SEM (error bars). Scale bar, 100 μm