Fig. 4. Cyclopamine inhibits SVZ cell proliferation in vivo. (A,B,E) Cross section through the forebrain SVZ of an adult mouse showing normal BrdU incorporation (arrows in A,B) or the expression of GFAP and Nestin (E) following one week's injection of HBC carrier (cyclodextrin) alone. Animals were perfused 12-24 hours after the last injection. (C,D,F) Decrease of BrdU⁺ cells in adult mice treated with cyclopamine for one week (C,D) does not lead to the loss of Nestin⁺ or GFAP⁺ cells (F). (G) Quantification of the number of BrdU⁺ cells in the SVZ of control and cyclopamine-treated adult mice. Counts are averaged and shown per section. Error bars=s.e.m., n=13 for control HBC-injected mice and n=18 for cyclopamine-injected mice in four independent experiments pooled together. Out of 18 cyclopamine-injected mice, three animals did not respond, five animals decreased the number of BrdU⁺ cells by 50%, and ten animals reduced incorporation by 100%. No reduction was observed in the HBC-injected mice. (H) RT-PCR of fresh SVZ tissue from adult control or cyclopamine-treated mice, dissected 4 hours after the last injection. Hprt levels are used as loading controls.