FIGURE 5. Functional capillary density (FCD) over the 10-day observation period within the proximal (A), middle (B), and distal part (C) of control flaps (white circles), heat shock-preconditioned flaps (gray circles), and heat shock-preconditioned flaps treated with SnPP-IX (black circles). Note the preservation of FCD in heat shock-preconditioned flaps. In contrast, control and in particular SnPP-IX-treated flaps show a significant decrease of FCD in the proximal and the middle area, and a complete abrogation of capillary perfusion in the distal part of the flaps. Data are mean ± SEM. *P < 0.05, **P < 0.001 versus control. ^#P < 0.05, ^##P < 0.001 versus heat shock.