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

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.

Comparison of Survival of Human Dermis, AlloDerm and Terudermis Graft in Nude Mous

Numerous materials, both autologous and nonautologous, have been used for augmentation of sunken areas and each has its own limitations. The ideal material for augmentation should not be absorbed in any manner. This study is designed to assess the survival of human dermis, AlloDerm and Terudermis graft according to the volume and histologic change. Twenty four nude mice, weighing about 50 grams and of 5 weeks of age were used. Human dermis was obtained from patients' buttock for dermofat graft. AlloDerm is an acellular dermal matrix obtained from human cadaveric skin. Terudermis is a bilayer membrane composed of bovine collagen matrix and a silastic membrane which functions as the epidermis. Eight graft pieces standardized to 1x1x 0.1 cm size were used in each group. The prepared graft was implanted at the back of the nude mouse. Biopsy specimens from each implanted area were taken 1, 4, 12 and 24 weeks later. The initial volume of the graft was measured by immersing it in a 2 cc of normal saline and the volume of fluid displaced was recorded. The changes of graft volume during the graft period were measured by the same method. The initial shape of the graft was maintained up to 24th week in The AlloDerm graft group. The volume of each graft decreased from initial 0.16 ml to 0.06 ml(34% of initial volume) on the 24 th week in Human dermis, from 0.15 ml to 0.12 ml (74%) in AlloDerm , and from 0.15 ml to 0 ml (0%) in Terudermis . In the human dermis graft group, some epidermoid cysts derived in hair follicles, appeared on the 24th week in dermis. The original structure of human dermis and Terudermis disappeared but the structure of AlloDerm remained until the 24th week after implantation. Our experimental study suggests that AlloDerm could be a safe material as an implant for permanent augmentation. In addition, use of AlloDerm could eliminate the concern about defect of a donor site and avoid complications such as epidermoid cysts. However the choice of graft for augmentation should be remained to the clinical situations.