A skin explant model for studying <scp>UV</scp> ‐induced <scp>DNA</scp> damage and repair

There is a growing need for a skin model that combines the natural physiology of skin while reducing reliance on mice. Natural physiology is achieved by using fresh, intact skin explants sourced from living organisms such as humans or mice. This study focused on the standardization and characterization of an in vitro mouse skin explant model for investigating solar ultraviolet (sUV)-induced skin damage. We developed a protocol to use skin explants derived from the discarded tissue of mice after euthanasia. These explants consist of intact dermal and epidermal layers suspended in cell culture medium and maintained in vitro. To assess the viability of the skin explants, we evaluated tissue morphology (via hematoxylin and eosin [H&E] staining), viability markers, and DNA damage markers. Our ex vivo model preserves the key characteristics and physiological responses of in vivo skin for short incubation periods, while minimizing the use of mice. This model enables the study of DNA damage and repair, and it has broad applications, including studies on skin photoprotection, topical treatments, drug development, and cosmetics.