Expression of Fas, Fas Ligand, bcl-2 in Fetal Wound Healing of Rats

ABSTRACT

Cutaneous wound healing in adult humans and higher vertebrate animals results in scar formation. In contrast, both human and animal fetuses at early gestational ages exhibit skin wound healing without scarring. A recent study has suggested that apoptosis occurs and plays an important role in achieving a decrease in cellularity during skin wound healing. The purpose of this study is to reveal the hypothesis the apoptosis may decreases the inflammatory infiltrates in fetal skin wound healing and may affect the fetal scarless wound healing. Open full-thickness incisional skin wounds were created on fetal rats at gestational ages 16 days(term= 21days). Wound were harvested at 24 hour(n=15), 72 hour(n=15), 120 hour(n=15). Adult skin wound was harvested at 24 hour(n=15), 72 hour(n=15), 120 hour(n =15). The wounds were fixed and stained with hematoxylin and eosin, TUNEL stain, immunohistochemical stain for Fas, Fas ligand, bcl-2. Fetal wounds was healed without scar formation and with regeneration of normal dermal and epidermal appendage architecture. Immunohistochemical staining for Fas, Fas ligand shows sparse positive cells in squamous epithelium of the both adult and fetus, there are no difference of expression between two groups. Immunohistochemical stainings for bcl-2 shows no positive cells in both adult and fetus. The apoptotic index of adult is 0.65+/-0.32 and fetus is 0.56 +/-0.37(p=0.464), there is no significant difference stastically between two groups. These data indicate that apoptosis is not likely to be related to decreased infiltration of inflammatory cells that is main factor of scarless fetal wound healing.