Fig. 4

NRG1-III improves neonatal SMA motor axon conduction speed but does not prevent degeneration A A schematic of the ex vivo nerve muscle preparations for stimulating L1 VR and recording from the quadratus lumborum (QL) muscle. B Representative traces from the QL muscle in WT, WT NRG1-III + , SMA, and SMA NRG1-III + mice at P2. C Conduction velocity and D CMAP amplitude from the QL muscle of WT (n = 9), WT NRG1-III + (n = 9), SMA (n = 7), and SMA NRG1-III + (n = 5) mice at P2. E Representative confocal images of P2 QL muscle NMJs stained with α-bungarotoxin (α-BTX, red), synaptophysin (Syp, purple), and SMI312 (green) (scale bar: 20 μm). F NMJ innervation in the L1 QL muscle of WT, WT NRG1-III + , SMA, and SMA NRG1-III + (n = 3 each) mice at P2. G Serum NF-L concentration of WT, WT NRG1-III + , SMA, and SMA NRG1-III + (n = 5 each) mice at P2. Data represents means and SEM. Statistical analysis was performed in (C, D) and (G) using one-way ANOVA; and in (F) using unpaired t test. Significance of WT compared to SMA NRG1-III + and WT NRG1-III + compared to SMA not included. Significance: *p \(\le\) 0.05, **p \(<\) 0.01