Figure 7

Cellular birth dating in the regenerating radial nerve cord. (A) Quantification of the percent of BrdU-labeled nuclei for each group of regenerating animals that were injected with BrdU at different time points and sacrificed at 62 dpi. (B) BrdU-labeled nuclei (green, arrows) among Hoechst-labeled nuclei (red) in the radial nerve cord at the injury site of an animal injected during the second week of regeneration. (C) Triple labeling showing Nurr1-expressing cell (red, arrow) with BrdU-labeled nuclei (green) in the hyponeural compartment at the injury site. Blue labeling is Hoechst dye. (D) Quantification of the percent of Nurr1 labeled neurons that were BrdU-labeled for each group at 62 dpi. The only neurons labeled with BrdU at 62 dpi were from the animals injected during the second and third weeks of regeneration (groups 2 & 3). Each point represents the mean ± S.E. of at least three animals. When compared to distal, significant differences are observed at various stages in the injured area. Similarly, significant cell division occurs in the proximal and distal area at G4. *p < .05, **p < .01. Scale bars = (A) 50 μm, (B) 25 μm.