Figure 5. Ependymal Cells Are Activated by Injury.

Uninjured and adjacent injured segments from mice 4 d after a dorsal funiculus incision. Recombined cells leave the ependymal layer in the injured segments (arrowheads). (A and B) Ki67 immunoreactivity indicates ependymal proliferation in the injured, but not in the uninjured segment. Migrating recombined cells lose Sox3 expression (D), but most are Sox9 immunoreactive, and a smaller population is GFAP immunoreactive (F–I). Some ependymal cells within the ependymal layer (outlined by hatched line in [I]) become GFAP immunoreactive (arrows). (J and K) Electron micrographs of an extended ependymal cell with a dense filamentous matrix (f) in the cytoplasm 4 wk after injury in a FoxJ1-CreER mouse. n, nucleus.

Scale bars indicate 25 μm in (A–H), 10 μm in (I), 1.5 μm in (J), and 0.2 μm in (K).