Fig. 6

C6 antisense-mediated MAC inhibition protects from synaptic alterations. Quantification of synaptophysin (SYP) positive punctae showed a significant decrease of synaptic densities (*p < 0.05) in the no drug (n = 4) compared to the C6 antisense-treated mice (n = 6), post-relapse phase. Differences between groups were analyzed by using the One-Way Analysis of Variance test. Data are expressed as the average (mean) ± SEM. Statistical differences are indicated (*p < 0.05, ***p < 0.001). Controls are healthy mice injected with adjuvant only (n = 6) (a). Pearson’s correlation coefficient showed a significant negative correlation between SYP and the C9 marker of MAC (coefficient, r = – 0.74, ***p < 0.0001), in the mouse spinal cord (n = 29 corresponding fields plotted) (b). Histological analysis of paraffin spinal cord sections from no drug mice showed low densities of SYP+ punctae (arrow pointing to a synapse), sign of synaptic alterations or loss (c), abundant C9 reactivity (arrows) (d), and ionized calcium-binding adapter molecule 1 (IBA-1) positive microglia/macrophages with a morphology consistent with an activated status (e). In contrast, histological analysis of spinal cords from C6 antisense-treated mice showed abundant SYP+ punctae (arrows) (f), sparse C9 reactivity (arrows) (g), and IBA-1+ microglia with a morphology consistent with a resting status (h). Scale bars: (c-h) 10 μm. Hematoxylin was used as counterstain in (c-h)