Fig. 6.

IFB-088 treatment improves C3-PMP22 mice quadriceps femoral nerve morphology. Toluidine blue–stained semithin sections of quadriceps femoral nerve from a female and b male WT mice treated with vehicle b.i.d. and C3-PMP22 (C3) mice treated with vehicle b.i.d. or IFB-088 at 0.5 or 1 mg/kg b.i.d. for 12 weeks. Scale bar, 10 µm; g-ratio measurement has been performed on toluidine blue–stained semi-thin sections. c Scatter plot of quadriceps femoral nerve g-ratios from WT mice treated with vehicle b.i.d. and C3-PMP22 (C3) mice treated with vehicle b.i.d. or IFB-088 at 0.5 or 1 mg/kg b.i.d. Note the “cloud” of axons with diameter lower than 1 µm present only in C3-PMP22 nerves (untreated and treated) and the considerable increase in the number of myelinated axons larger than 5–6 µm in IFB-088-treated C3-PMP22 nerves. n = 5–8 nerves per condition. d Percentage of myelinated axons per axons size; n = 5–8 nerves per condition. e, f TEM analysis of quadriceps femoral nerve from C3-PMP22 (C3) mice treated with vehicle b.i.d. or IFB-088 at 1 mg/kg b.i.d. e In C3-PMP22 vehicle–treated nerves, small-calibre axons are abnormally hypermyelinated (black dotted arrows). Treatment with IFB-088 results in normal-looking myelin in axons larger than 1 µm (red arrows) or in almost no myelin in smaller axons (blue larges arrows). f In C3-PMP22 vehicle–treated nerves, large-calibre axons are basically amyelinated or with only a very thin layer of myelin (left panel). After treatment with IFB-088 (right panel), a subgroup of large-calibre axons showed a properly compacted (albeit still rather thin) myelin sheath. A side-by-side comparison of myelination in two axons with similar calibre is shown in the lower panel