A standardized model of partial thickness scald burns in mice

Background. Large mammal partial thickness wound models were developed primarily for their anatomical similarity to human wounds, yet lack the economy, ease of handling, and statistical power afforded with rodent models. Previous small mammal models of partial thickness burn injury have failed to demonstrate complete reepithelialization in less than 3 weeks. We present a murine partial thickness scald model with a reepithelialization rate comparable to that of porcine wound models. Methods. Thirty-eight adult male mice were secured in a burn template allowing exposure of a 2 x 3-cm area of the shaved dorsum to 60°C water for 45 s, followed by 4°C water for 45 s. Four wounds were harvested daily on Postburn Days 1-7, 10, and 14 for histologic evaluation. Results. Histologic evidence of partial thickness dermal injury with sparing of dermal appendage epithelial cells was seen in all wounds. Of 134 wound sections evaluated 26 contained some areas of full thickness dermal injury, with only 8 of these 26 sections showing full thickness injury in 50% or more of the cross-sectional area of the wounds. Complete wound reepithelialization was seen between Postburn Days 10 and 14. The viable dermal thickness in all burn cross sections was at least 40-80 μm, and up to 1400 μ in reepithelialized wounds. Conclusions. This murine model of partial thickness scald injury provides a standardized thermal wound with consistent depth of injury, low mortality, and a reepithelialization rate between 10 and 14 days. A simple protocol allows easy production of 30- 50 wounds daily with one technician.