The Construction of Photoaged Skin Animal Model

Objective: To treat and prevent photoaging in humans, hairless mice were exposed to ultraviolet B(UVB290-320nm) to study skin changes in stigmata, epidermis, dermis, dermal structural elements, these changes are similar to humans induced by chronic ultraviolet. Methods: Twenty hairless mice were exposed in ultraviolet B (UVB) for 20 weeks, total dose 5.9J/cm2. After irradiation, the dorsal skin of animals were analysed by computer imaging analysis system, histological and specific strains. Result: Hairless skin in ultraviolet irradiated, the stigmata are coarse, deepening wrinkles, the epidermis became hyperplastic and skin thickened. Dermal-epidermal basement membrane was thick and un-regular. PAS positive substances were increased. Fibroblasts were increased. Mononuclear cells infiltrated into the dermis. The content of collagen was decreased. Elastic fibers were thickened, proliferated and coalesced into extensive denaturalization. Conclusion: Chronic exposure of hairless mice to ultraviolet B is associated with inflammation. The changes of dermis and dermal structural elements are pathologic bases of photoaged skin. So this model is a perfect photoaged animal model.