Résumé
The cornea is the transparent tissue on the eye surface, where light enters the ocular machinery. It has two main roles: light refraction, and protection of the inner eye components. Proper light transmittance requires corneal transparency, which can be compromised by injuries and corneal diseases. Understanding the physiology of the cornea in health and disease is thus important for proper treatment of corneal malfunction, and prevention of corneal blindness. Up to date, the majority of research relies on rodent models and cell-based systems. In this thesis, I studied the corneal formation and injury response in the zebrafish, which has many beneficial traits as a model organism, is known for its regenerative capacity, but has been somewhat overlooked in corneal studies.This study focused on the epithelium, the outermost cellular layer of the cornea. First, I delineated the epithelial maturation timeframe, by studying the cell appearance, proliferation, gene expression, and the innervation pattern in young fish. The analysis revealed two main phases: a morphogenetic period of circa three weeks, leading to epithelial stratification, and a maturation period that lasted up to later juvenile stages. These observations have implications for future corneal studies in young fish.In this thesis, I also applied a mechanical surface abrasion method to study the injury response on the zebrafish corneal epithelium. The results showed that a central corneal wound close within three hours in a process that does not necessitate proliferation. The data also revealed consistent downregulation of the gene pax6a on the migrating epithelium, and showed the importance of TGFβ signaling in the healing process.Due to the small amount of previous research on the zebrafish cornea, there is a lack of markers that would enable the identification of epithelial cell populations, and refined experimentation with genetic tools. In this work, I identified a type I keratin, krtt1c19e, as a potential marker for limbal stem/progenitor cells in the mature cornea. Overall, these results demonstrate the utility of the zebrafish in corneal studies, and open up new avenues for corneal research in this species.