FIGURE 8.

Ultrastructural abnormalities of peripheral nerves in Δ10 mice. A and B, representative electron micrographs of sciatic nerve longitudinal sections, at the level of NR, from 10-month-old mice WT and Δ10 mice (three mice/genotype). A, cytoplasmic glial loops contacting the axons at paranodes are globally normal in mutant mice, and the transverse bands (arrowheads) are visible in Δ10 mice as well as in WT mice. Black asterisks locate NR. B, Δ10 mice present swollen and shorter NR with an increased number of intra-axonal vesicles (arrows) as compared with WT mice. Lower panels correspond to high magnifications of upper panels at the level of NR. Dashed lines delineate NR. C, representative transversal sections of phrenic nerves at the level of NR showing that the axon of Δ10 mice contained a higher number of vesicles (arrows, arrowheads), some with an electron-dense core (arrows) (three mice/genotype). D and E, transversal sections of phrenic nerve at the level of NR (D) and the internode (E) showing that the axons of Δ10 mice present microtubules gatherings close to and surrounding mitochondria (arrowheads). F, expression of neurofilament subunits NF-H, NF-M, and LF-L, neuronal β-tubulin (β3-tub) and clathrin in sciatic nerves from 8-month-old WT and Δ10 mice evaluated by immunoblotting. Protein lysates were the same as those used to quantify the expression levels of the proteins of the nodes of Ranvier. Immunoblots for β-tubulin and clathrin are consequently identical to those presented in Fig. 7D. Clathrin was similarly used to normalize protein expression. Scale bars, A and B, 0.5 μm; C and D, 200 nm; E, 100 nm.