Skin aging involves both chronological and photoaging processes. The effects of these processes are often overlapping and include changes in both the stratified epithelium and the fibroblast-rich dermis. Wound healing is frequently delayed with aging and can result in
scarring. A skin equivalent model can be used to study the role of cells and the extracellular matrix in the process of wound healing. Current studies using this model employ a full-thickness
wound placed atop a nonwounded dermis to mimic a partial-thickness
wound. However, a true reproducible partial-thickness
wound model has yet to be described. In this study, we investigated whether a
laser-wounded skin equivalent would be a useful partial-thickness wound healing model. Three
lasers were compared for the ability to generate a reproducible
wound: an
erbium-YAG, a high-powered excimer, and a low-powered
excimer laser. Reepithelialization ability was tested using newborn and adult skin keratinocytes, adult esophageal keratinocytes, and cdk4-overexpressing newborn keratinocytes. Keratinocyte compartmentalization and basement membrane formation were assessed by immunofluorescence. The
erbium-YAG and high-powered
excimer laser cut reproducible
wounds but left the remaining surface either discolored due to thermal damage and/or ragged; keratinocytes were unable to migrate into the
wound area. The low-powered
excimer laser cut reproducible
wounds, leaving the cut surface intact and visibly unaltered; keratinocytes reepithelialized the
wound in a
collagenase-dependent manner within 3 days; and return of compartmentalization and basement membrane occurred within 14 days. The
laser-wounded skin equivalent is an adjustable, reproducible partial-thickness
wound model where keratinocyte biology akin to in vivo can be studied, and will be useful to study the effects of aging on wound healing.