Fig. 4. Keratinocyte proliferation during wound healing. (A-F) At least three mice of every group were injected intraperitoneally with BrdU and sacrificed after a labeling period of 1 hour. Skin sections were stained for detection of BrdU-labeled S-phase nuclei (green, arrows) and for keratin 14 marking the epidermis (red). Transgenic animals (A,C,E) exhibit a higher number of labeled nuclei at the wound edge at 3, 5 and 7 days post wounding compared with wild-type animals (B,D,F). 3 days post wounding (A,B); 5 days post wounding (C,D); and 7 days post wounding (E,F). Bars, 50 µm.