Abstract: Objective To investigate the time course of changes in the expression of fibroblast activation protein (FAP) during
healing of skin scald burns in rats. Methods Adult Wistar rats were randomized into two equal groups (n=42) and subject to
superficial second degree and deep second degree scald burns on the dorsal skin groups, with 6 normal rats serving as the
control group. At 6 h, 12 h, and 1, 3, 7, 14, and 21days after burns, 6 rats from each group were sacrificed to detect FAP
expression by immunohistochemistry and Western blotting. Results FAP was expressed on the cell membrane and in the
cytoplasm of the fibroblasts, especially those around the neovessels. In both burn groups, FAP expression increased
significantly at 6 h after burns. In superficial burn group, FAP expression was comparable between 6 and 12 h and between 1
and 3 days (P>0.05), but showed significant differences between the other time points (P<0.05). In deep burn group, FAP
expression was comparable between 12 h, 1 day and 3 days (P>0.05) but differed significantly between the other time points (P<
0.05). In both burn groups, FAP expression reached the peak level at 7 days followed by a gradual declination. At 21 days after
the burns, FAP maintained a significantly higher expression level than the control level (P<0.05). Conclusion The time course
of the changes of FAP expression following scald burns suggests an important role of FAP in the healing process of scald burns.