Fig. 5.

Neurogenesis in cultures initiated from adult optic nerve. Low-buoyancy cells were isolated from adult optic nerve and placed in culture. At 1 DIV, a mixture of immature and differentiated cell morphologies was present (A).Arrows in A show typical glial profiles present at 1 DIV. On days 3 (B) and 7 (C), small proliferating clusters became apparent. After 3 weeks in the presence of FGF-2, a small but significant proportion of cells (0.8%) were able to differentiate into β-tubulin-positive neurons. In D–K, cells were treated with BrdU for 72 hr (days 12–14) and then switched to differentiation medium on day 14. Cells were fixed on day 28 and evaluated for BrdU and lineage-specific markers. Total nuclei are shown in blue (D, G). BrdU-positive nuclei (white) in the same fields are shown along with β-tubulin (red, E) or 200 kDa neurofilament (green, H).F and I, respectively, show multiple labeling for β-tubulin (red), GFAP (green), and O4 (magenta) or 200 kDa neurofilament (green), tau (red), and GFAP (magenta). Enlargements of the areas boxed in E andH clearly show that the neuronal nuclei are BrdU-positive (white in J andK). Scale bars: A–C, 60 μm;D–I, 35 μm; J, K, 15 μm.