Physical forces make rete ridges in oral mucosa.

Rete ridge has important functions in the epidermis, but the current tissue engineered oral mucosa or skin equivalents are generally lack of this structure. To regenerate a rete ridge structure in the oral mucosa equivalents, we firstly attempted to make clear how rete ridge is formed in the oral mucosa and the preliminary study disclosed the mechanical stress evoked the morphogenesis of rete ridge. In this paper, we make a hypothesis that the morphogenesis of rete ridge is elicited by the physical forces and proceed with the internal pushing forces derived from the keratinocyte division, among these process, the activated ERK and PC cascades, accompanied with the MMPs liberated growth factors are working together to induce the keratinocyte proliferation, these cell divisions produced internal forces, which not only push the keratinocyte stem cells and progenitor cells to migrate in the contrary directions but also in turn to activate the ERK and PC cascades, meanwhile, the activated MMPs degrade the ECM of lamina propria, under these internal pushing forces and the remodeling of lamina propria, rete ridge is gradually formed. This hypothesis gives us the possibility to regenerate the rete ridge structure in the tissue engineered oral mucosa or skin equivalents through simulating the morphogenesis of rete ridge. Crown