Figure 3. Immunohistochemical evidence of hypoxia during wound healing. In normal rat skin (A), the pimonidazole adducts were detected in the epithelial layer (A1), hair follicles (A2), and sebaceous glands (A3). At day 1 (B), we did not detect any reactivity for the hypoxia marker in the wounded tissue. On day 2 (C), macrophages (C4) and endothelial cells (C5) started to exhibit immunoreactivity at the border of normal and wounded tissue. By day 4 (D, E), maximal hypoxia reactivity was observed. The epithelial layer (D6) and granulation tissue both were highly reactive. Macrophages (D7) and endothelial cells (D8) in small blood vessels could be seen with evidence of pimonidazole adduct formation. By day 8 (F), the immunoreactivity was limited to the epithelial layer, remnant blood vessels (F9), and macrophages in the scar tissue. Orientation of the figures is shown as outer layer (OL) and wounded tissue (WT).