Topical thyroid hormone accelerates wound healing in mice

Although the physiologic role of thyroid hormone in skin is not well understood, mounting evidence suggests that T-3 plays an important role in epidermal proliferation. The goal of this project was to evaluate whether the topical application of supraphysiologic doses of T-3 could accelerate wound healing. We evaluated mice treated with topical T-3 vs. the same mice receiving vehicle alone (Novasome A). Ten-millimeter diameter (79 mm(2)) dorsal skin wounds were established in all animals, and wounds were remeasured 4 d after injury. All animals were evaluated twice: once with the T-3 treatment and once with the vehicle alone. Daily topical application of 150 ng T-3 resulted in 58% greater wound closure relative to wounds on the same animals receiving vehicle alone (P < 0.001). Furthermore, we determined that wound healing- associated keratin 6 protein expression in hair follicle keratinocytes increased in a dose-dependent manner in vivo during topical T-3 treatment. The data support our previous hypothesis that T-3 is necessary for optimal wound healing. Now, we further suggest that topical thyroid hormone may be an inexpensive agent to hasten healing of certain wounds.