Figure 4.

Demyelination in ventral roots of double-mutant mice. A–N, Semithin (A) and electromicroscopical (B–N) analyses of transverse (A–L) or longitudinal (M, N) sections through ventral roots from double mutants. A, B, The same macrophage (mφ) inside a myelinated axon (a). C, A foamy macrophage between the axon and myelin sheath (my). D, E, I, J, Macrophages containing myelin debris (arrows). In F (and enlarged inset in G), macrophage processes (arrowheads) strip the basal lamina away (asterisk) from the Schwann cell. H, Uncompaction of myelin lamellae (arrows). I, Macrophage found within the loose basal lamina (asterisks) of the Schwann cell. K, Demyelinated fibers. L, Remyelinating fiber. M (inset enlarged in N), A macrophage penetrating through the paranode (pn). Scale bar: (in M) A, 30 μm; G, N, 1 μm; H, 1.5 μm; B–F, M, I, J, 2 μm; K, L, 3 μm.