The adhesive heterogeneity of different compartments of oral mucosal rete ridges

Rete ridges play a critical role in maintaining epidermal structure and mechanical properties. Notably, rete ridges can be divided into three compartments: the base, slope and tip. The present study aims to explore whether these three compartments have distinct adhesive functions. We collected 28 normal masticatory mucosae to prepare paraffin-embedded sections. Immunohistochemistry and immunofluorescent staining were used to analyse the expression pattern of integrin alpha 6 and beta 4 in different compartments of the rete ridges. To observe whether the different compartments had distinct adhesive forces, dermal-epidermal junction separation experiments were performed by peeling the oral epithelium from the lamina propria after treatment with cold saline for 72 h. The results showed that integrin alpha 6 and beta 4 prefer the basal layer keratinocytes closely adjacent to the base compartment of the rete ridges. The oral mucosal epithelium separated from the underlying lamina propria at the tip of rete ridges when they were peeled after the cold saline treatment. In conclusion, the adhesive force of the basal layer keratinocytes at the base of the rete ridges is stronger than at the tip.