Fig. 1: Structural characterization of SGN myelin in the cochleae of 10-month-old APOE3 and APOE4 mice.

A TEM images of the SGN ultrastructure in the cochleae of WT, APOE3 and APOE4 mice. Scale bar: 1 μm. Solid frames denote the enlarged region showing axonal demyelination (APOE4) and compact myelin (APOE3). Scale bar: 0.5 μm. B Percentage of demyelinated SGNs in the cochleae of WT, APOE3 and APOE4 mice (20 SGNs in every view, each dot represents all SGNs in a microscope field, n = 5; ns not significant, *P < 0.05 by one-way ANOVA). C Myelin g-ratios in the SGNs of WT, APOE3 and APOE4 mice (20 SGNs in every view, each dot represents all SGNs in a microscope field, n = 13; ns not significant, ***P < 0.001 by one-way ANOVA). G-ratio in the APOE4 SGNs was lower than that in WT and APOE3 controls. D MBP protein expression in the cochleae of WT, APOE3 and APOE4 mice. The expression of MBP was significantly downregulated in the cochleae of APOE4 mice compared with WT and APOE3 controls. E Relative protein expression of MBP in the cochleae of WT, APOE3 and APOE4 mice (n = 6; ns not significant, *P < 0.05 by one-way ANOVA). F Relative mRNA expression of MBP in the cochleae of WT, APOE3 and APOE4 mice (n = 6; ns not significant, *P < 0.05 by one-way ANOVA).