MBP is toxic to primary hippocampal neurons <i>in vitro</i>.

<p>(A) Morphology of MBP-treated neurons. Primary cultured neurons with or without eGFP overexpression (green) were incubated with 50 µg/mL MBP for 24 h. HBSS was used as control. Degeneration of soma and neurites is indicated with arrows. Scale bar, 50 µm. (B) Neuronal degeneration induced by 24-h MBP incubation at the indicated concentrations. Details are shown in the enlarged images. Scale bar, 100 µm. (C) Time-lapse imaging of neurons incubated with HBSS or 50 µg/mL MBP. Normal morphology is indicated by arrows, and degeneration by arrowheads. Scale bar, 100 µm. (D) Neuronal death induced by 24-h MBP incubation at the indicated concentrations, assessed by DAPI/PI double-staining. Dead cells are PI-positive. Scale bar, 100 µm. (E) Statistical analysis of (D). Incubation with 30 and 50 µg/mL MBP induced cell death (***P<0.001; ns, not significant; one-way ANOVA with Dunnett's post-test; n = 5). (F) Statistical analysis of PI-positive neurons after HBSS or 50 µg/mL MBP incubation for different times (**P<0.01, ***P<0.001; two-way ANOVA with Bonferroni's post-test; 6 h, n = 6; 12 h, n = 10; 24 h, n = 6). (G) Statistical analysis of PI-positive neurons after 24-h incubation with HBSS, mouse IgG (mIgG), BSA or MBP (50 µg/mL each). In contrast to MBP, no cell death was induced by mIgG or BSA (***P<0.001; ns, not significant; one-way ANOVA with Dunnett's post-test; n = 5). Data are mean ± SEM.