Human oral buccal mucosa reconstructed on dermal substrates: a model for oral epithelial differentiation

To develop a model for the study of oral epithelial differentiation, we reconstructed artificial buccal mucosa equivalents using keratinocytes and fibroblasts or de-epidermized dermis derived from noncornifying buccal mucosa. The buccal mucosa equivalents reconstructed in this way showed a morphology closely mimicking that of their in vivo counterparts. There was no formation of horny layers and granular layers. The expression of various differentiation markers such as K13, involucrin and loricrin was consistent with that of the in vivo state, and indicative of the hyperproliferative state. We also demonstrated that the differentiation of oral epithelial cells was influenced by the de-epidermized dermis and subepithelial fibroblasts. The epidermis of buccal mucosa equivalents seemed to be less sensitive to retinoic acid than that of the skin. The effects of calcipotriol on the buccal mucosa equivalent and the skin epidermis were different. These results suggest that the pharmacological effects of retinoic acid and calcipotriol on the buccal mucosa are different from those on the skin. A useful model system for studies of oral keratinocyte differentiation and pharmacological research could be based on these artificial buccal mucosa equivalents.