Figure 6. Level of phenotypic rescue is inversely correlated with the extent of neuromuscular synapse pathology.

(A) Immunohistochemistry of cervical spinal cord sections from mice administered TM at various time points during the course of the disease revealed gems (arrows) and normal cytoplasmic staining only in P4-treated mutants. Scale bars: 125 μm and 5 μm (insets). The timing of SMN restoration correlates closely with (B) AChR cluster development as well as (C) the ability to clear presynaptic NF aggregates by P17. Early treatment resulted in greater sophistication of the postsynapse and reduced NF in nerve terminals. *P < 0.05; **P < 0.01; ***P < 0.001; 1-way ANOVA. Note: more than 500 AChR clusters (for postsynaptic specialization) and more than 50 endplates (for NF accumulation) were examined in at least 3 mice per time point. Data are represented as mean ± SEM.