Porcine ear skin:: an in vitro model for human skin

Background/purpose: Porcine ear skin is used in studies of percutaneous penetration as a substitute for human skin. The structure of this tissue, including hair follicles, was studied qualitatively and quantitatively in comparison with human skin. Methods: Sections of shock-frozen biopsies, biopsies embedded in paraffin and cyanoacrylate skin surface biopsies were investigated using microscopy. The thickness of the different skin layers and the follicular characteristics were determined. Results: The thickness of the stratum corneum was 17-28 mu m, whereas the viable epidermis was 60-85 mu m thick. On 1 cm(2), 11-25 hairs were detected, showing a diameter of 58-97 mu m and a maximal extension depth of 0.96-1.38 mm into the skin. The orifices of the porcine infundibula showed a diameter of approximately 200 mu m. Conclusions: The results obtained are similar to those of human skin, indicating the suitability of this porcine tissue as a model for human skin.