A Histological and Molecular Analysis of Tooth Regeneration in Monodelphis domestica

Abstract

We aimed to gain insight into the differences between dental organs with different replacement capacities in the same animal, the gray short-tailed opossum (Monodelphis domestica), with regards to the fate of the successional dental lamina. The methods used to aid our research included three-dimensional reconstructions of serial histological sections, immunohistochemistry assays for studying expression of epithelial stem cell marker Sox2, proliferation, apoptosis, basement membrane integrity and innervation around the canine (non-replacing) and third premolar (replacing) dental organs and laminae. Our results show that the dental successional lamina developed at multiple tooth positions, with the laminae attached to non-replacing teeth starting to regress, in association with lack of Sox2 expression, reduced proliferation, increased apoptosis, disruption of the basement membrane and loss of innervation. In comparison, the successional lamina on the replacing tooth expressed Sox2, exhibited increased proliferation and reduced apoptosis and constant innervation throughout the studied stages. We believe these differences underlie the survival of the successional dental lamina and its capacity to fuel the formation of a new tooth.