Fig. 4. RA increases SVZ cell proliferation in explants. (A,B) Bis-benzimide staining of P2 slices cultured for 2 DIV with vehicle (Veh, A) or 10 µM RA (B) and re-sectioned at 40 µm. The SVZ and RMS stain as a dense band that expands after RA treatment. (C-F) BrdU immunostaining of the sections in A and B; slices were exposed to BrdU for 2 hours prior to fixation. More SVZ cells incorporated BrdU with RA treatment (D,F) compared with control (C,E). (E,F) Show regions of SVZ approximated by the boxed area in C. (G) Quantification of BrdU-positive cell numbers per fixed SVZ area (boxed region in C). ^**Denotes P<0.01. (H,I) TUNEL staining of control (H) and RA-treated (I) explants. No difference in TUNEL-stained cells (arrows) was seen (see text for quantitation). CTX: cortex. OB: olfactory bulb. Asterisk marks lateral ventricle in A. Scale bar: in B, 100 µm for A-D and 25 µm for E,F; in I, 50 µm for H,I.