Fig. 1.

Myostatin deletion increases the number of nerve fibres. (A) Representative images showing transverse sections through the ischiatic nerve of 6-month-old mstn^+/+ and mstn^−/− mice. Myostatin deletion-induced hyperplasia results in an increased cross-sectional area. Scale bar: 20 μm. (B,C) Quantification of the average nerve fibre number in the radial (B) and ischiatic (C) nerves of 6- and 12-month-old mstn^+/+ (red) and mstn^−/− (green) mice (n = 3 mice per group). Higher values were observed in mstn^−/− nerves at both ages compared to age-matched mstn^+/+ counterparts. Two-way anova shows a significant genotype-dependent increase in nerve fibre number (P < 0.001). mstn^+/+ animals 12 months old showed decreases in the number of nerve fibres for both radial (B) and ischiatic (C) nerves when compared to 6-month-old animals of equivalent genotype (n = 3 mice per group), but not mstn^−/− animals. Two-way anova shows significant age-dependent decreases in nerve fibre number (P = 0.001 for both nerves). (D) Average nerve fibre number in the radial and ischiatic nerves of 6-, 12- and 24-month-old mstn^−/− mice. One-way anova was performed to measure the effect of age on nerve fibre number of the mstn^−/− mice (6- vs. 12- vs. 24-month-old mice). Significant reductions in the number of axons from 6 to 24 m were observed (n = 3 animals at each time point; *P < 0.001). Error bars are mean ± SEM.