Figure 5: Testing satellite cell role in maintaining EOM and diaphragm myofibres.
From: Muscle stem cells contribute to myofibres in sedentary adult mice
(a,c) Representative cross-sections showing outlined laminin+ myofibres in diaphragm and EOM at 12 and 20 months in Pax7CreERT2/+;RosaDTA/+ mice (see Fig. 3 for representative cross-sections of Pax7+/+;RosaDTA/+ mice). Histograms generated using MuscleQNT show relative frequency of myofibres sizes in muscles at 12 months (dark blue, control Pax7+/+, n=7; red, satellite cell-ablated Pax7creERT2/+, n=8) and 20 months (light blue, control Pax7+/+, n=5, pink, satellite cell-ablated Pax7creERT2/+, n=6) Scale bar, 100 μm in both panels. (b) Additional histograms for the diaphragm show frequency of fast MyHCI− and slow MyHCI+ myofibres. Permutation tests (see Methods) were conducted to determine whether counts of myofibres were significantly different in a particular bin between control and satellite cell-ablated muscles. Black asterisks indicate an empirical P-value of <0.05 and grey asterisks a value of <0.10 (see Methods). (d) Myonuclei are significantly longer at 20 months (two-tailed student t-test, *P<0.05), but number of myonuclei do not change between 12 and 20 months in the diaphragm (two-tailed student t-test).
