Superficial wounding model for epidermal barrier repair studies: Comparison of erbium:YAG laser and the suction blister method

Background and Objectives Wound-healing studies use mainly mechanical methods for wound induction, which are laborious and difficult to standardize. Objective of this study was to evaluate the Erbium:Yttrium-Aluminium-Garnet (Er:YAG) laser method as a model of epidermis ablation on human skin in vivo and to compare the quality and healing rates of Er:YAG laser and suction blister (SB) wounds. Materials and Methods Er:YAG laser and SB wounds were made on the forearms of 10 healthy volunteers. Post-wounding measurements including wound surface area (WSA) from photographs, wound depth from 3D volume analysis, trans-epidermal water loss (TEWL), laser doppler blood flow (LDBF), and optical coherence tomography (OCT) imaging were made daily over 7 days. Biopsies were taken on Days 4 and 7. Results 3D analysis showed laser wounds to be shallower and more uniform in depth than SB: 54±14μm versus 140±102μm, respectively, with histology demonstrating complete epidermal removal using SB. SB wounds were more variable in size with a WSA of 0.47±0.24cm ² compared to 1.17±0.14cm² for laser wounds. Healing rates were similar in both groups, as measured by TEWL, LDBF, and WSA. OCT imaging on Days 3-4 revealed new epidermis below the fibrin clot, similar to histology, and a visible stratum corneum on Day 7, but no apparent epidermal hyperplasia in contrast to histology. Conclusion Compared to the SB model, Er:YAG laser achieved rapid standardized epidermal ablation, which despite morphological differences, was similar in terms of epidermal regeneration/barrier formation. Lasers Surg. Med. 44: 525-532, 2012. © Wiley Periodicals, Inc.