[The significance and the expression of homeobox genes during human burn wound healing]

To investigate the expression of several homeobox genes during the wound healing in fetal and adult skin and their roles in fetal scarless wound healing.

The expressions of PRX-2, HOXB13, HOX2.2 and HOX2.3 during wound healing in fetal and adult skin were determined with in situ hybridization.

(1) PRX-2 positive expression could be identified in normal fetal and adult skin, especially in the fetus. But there was difference in location sites of the genes. The positive expression in normal fetal skin was mainly found in the peripheral cells at the hair shafts within dermal papilla layers and was also found in the epithelium. Nevertheless, weak positive expression of PRX-2 was found in the epithelial basal layer cells in normal adult skin but not in dermal tissue. There was strong positive expression of the PRX-2 in the tissue around the wound in fetus but not of that in adults except the epithelial basal layers. (2) Positive expression of HOXB13 could be identified in both normal fetal and adult skins. And the expression was concentrated mainly in hair follicle cells in the dermis and in the basal layer cells in the epithelium. Furthermore, the expression became weak after trauma, especially in fetal skin. (3) The positive expression of HOX2.2 and HOX2.3 in normal fetal skin was observed mainly in the whole layer of the epithelium and especially in the epithelial basal layers. Weak positive expression could be found in the dermis and strong expression found in the tissue near the wound. But there was no positive expression of the HOX genes in normal adult skin and wounds.

The difference in the HOX expression in fetal and adult skin wound healing might be the key factor leading to different wound healing. Homeobox genes might be closely related with the developmental biology.