Morphologic Development of Corneal Limbus

Abstract

Abstract: : Purpose: To analyse with histochemical and immunohistochemical techniques the morphology and the development of epithelial corneal limbus cells in human fetus and cadavers. Methods: Corneal limbus junction of epithelium of cornea and conjunctiva were obtained from ocular globes of five cadavers and twenty five fetus (range 8 to 37 weeks) and frozen in liquid nitrogen. The study was performed with cadavers and fetus obtain in legal pregnancy termination with the approval of Ethics Committee of university Paris V and in compliance with the Declaration of Helsinki. Semi–serial frozen sections were realised for classical HE, PAS and Alcian blue histological staining techniques. Then we selected sections and performed immunohistochemical methods to characterize expression of cytokeratin K3/12, K19, and MUC5AC by monoclonal antibodies. Results: In our early fetuses, we observed a very thick and dense corneal limbus epitelium below the stroma compared to the corneal epithelium. Basal layer cells were very dense and numbers of layers were three times higher. This area becomes less dense and thinner in older fetuses and adult. PAS and Alcian blue allowed the identification of goblet cells in the continuing conjunctival epithelium. Cinetik expression of immunohistochemical markers was observed in fetuses. Conclusions: Corneal limbal cells demonstrate a special morphology at the limbus in the area transition between cornea and conjunctiva. Limbal stem cells deficiency is a severe disease that needs to be more studied to define the function of limbal cells. A better characterization of the development of these cells may be interesting in the understanding of the physiopathology of corneal regeneration and its migration properties.

Keywords: cornea: epithelium • conjunctiva • microscopy: light/fluorescence/immunohistochemistry