Fig. 5

NRG1-III overexpression does not provide sustained improvement to SMA motor axon morphology or function A Representative EMG traces from the QL muscle in P12 mice. B Conduction velocity from the QL muscle of WT (n = 5), WT NRG1-III + (n = 5), SMA (n = 5), and SMA NRG1-III + (n = 4) mice at P12. C CMAP amplitude from the QL muscle of WT (n = 5), WT NRG1-III + (n = 5), SMA (n = 6), and SMA NRG1-III + (n = 4) mice at P12. D Cross-sectional area, E myelinated axon number and F Schwann cell number of L1 VRs in WT (n = 5), WT NRG1-III + (n = 5), SMA (n = 3), and SMA NRG1-III + (n = 4) mice at P14. G Representative EM images of L1 VRs in WT, WT NRG1-III + , SMA, and SMA NRG1-III + mice at P14 (scale bar: 2 μm). The orange arrow indicates a large myelin sheath. (H and I) Axon diameters and G-ratios of L1 VRs in WT and WT NRG1-III + H and SMA and SMA NRG1-III + I P14 mice. J Percentage of axons by axon diameter in L1 VR of WT (n = 4), WT NRG1-III + (n = 3), SMA (n = 4), and SMA NRG1-III + (n = 4) mice at P14. Data represents means and SEM. Statistical analysis was performed in (B)–(F) using one-way ANOVA; and in (J) using unpaired t test. Significance of WT compared to SMA NRG1-III + and WT NRG1-III + compared to SMA not included. Significance: *p \(\le\) .05, **p \(<\) 0.01, ***p \(<\) 0.001, ****p \(<\) 0.0001