Modeling the cornea: an architectural approach

Nowadays the mechanism regulating the corneal epithelium renewal still remains unclear. Until now it was thought to be the fact of stem cells distributed in the limbus, generating TA cells migrating towards the central cornea and responsible for its renewal. But Majo and Barrandon (Nature Oct 2008) showed the presence of stem cell within the corneal epithelium and the ability of this epithelium to renew without limbal contribution. They prove that the limbal epithelium was involved only in healing processes. To simulate and test the relevance of the different hypothesis a model able to map cells location precisely and analyse or predict their movements in function of the internal forces and tissue biomechanics must be created. In this project I have created a mouse cornea architectural model. It was based on three dimensional reconstruction of a mouse eye using histological cuts. The model include two main parameters; the curvature of the different eye part and their thickness. The techniques developed and used in this project are easily reproducible for the construction of other cornea or eye model of diverse species for instance. This model can be used in clonal analysis to locate cells or groups of cells three-dimensionally. Besides analysis of the corneal structure at the cellular level was performed by the observation of clones (expressing $\beta$-galactosidase), present in the limbus and cornea epithelium. Their location, form and orientation were investigated. This work provides a useful tool in the study of corneal epithelium renewal. Moreover it establishes the basis for the development of a future biomechanical model that will simulate tissue deformation, internal forces or cell movements. Studies of corneal parameters will be performed on enucleated eyes under normal physiological conditions inside an incubator regulating variables such as temperature, intraocular pressure or humidity level, currently develop in the laboratory