Acute Ultraviolet Radiation Perturbs Epithelialization but not the Biomechanical Strength of Full-thickness Cutaneous Wounds.

We hypothesized that priming of the skin with ultraviolet radiation (UVR) before being injured would enhance wound healing. Four groups, each comprising 20 immunocompetent hairless mice, were exposed to simulated solar irradiation in escalating UVR doses; 0 SED (standard erythema dose) = control, 1 SED, 3 SED and 5 SED. Twenty-four h after UV irradiation, inflammation was quantified by skin reflectance (erythema) and myeloperoxidase (MPO) tissue levels, and two 6-mm full-thickness excisional wounds and one 3-cm incisional wound were inflicted. Epidermal hyperplasia was assessed by quantitative histology. Five days after wounding, wound coverage by neoepithelium and wound width of the excisional wounds was quantified in hematoxylin-eosin sections, and breaking strength was measured in strips from incisional wounds. Erythema (P < 0.001), MPO levels (P < 0.0005) and epidermal cell layers (P < 0.001) increased dose-dependently by UV exposure of dorsal skin. In the excisional wounds, epithelial coverage decreased (P = 0.024) by increasing the UVR dose while there was no significant difference (P = 0.765) in wound MPO levels. Neither wound width (P = 0.850) nor breaking strength (P = 0.320) differed among the groups. Solar-simulated UVR 24 h before wounding impaired epithelialization but was not detrimental for surgical wound healing. This article is protected by copyright. All rights reserved.