Abstract
Purpose: :
The aim of this work is to study structural changes in keratoconic corneas by light microscopy and immunohistochemistry analysis.
Methods: :
Five keratoconic corneas obtained from patients who were submitted for keratoplasty were characterized by Hematoxylin-eosin and Periodic acid of Schiff staining and immunohistochemistry techniques to TuJ1, E-Cadherin, Laminin, PCNA, ErBb2, TGFß1, and metalloproteases 9 and 24. The samples were independent analyzed by two pathologist scoring the results in a scale 0 to 4+
Results: :
Epithelial cell layer present a hyperplasia area surrounding the ectasia and atrophy at the top. Light pathology confirm the breakdown on the Bowman membrane with disorientation of underlying stroma and an increase of keratocyte density. Stromal thinning at the site of the ectasia was also observed in all corneas. Immunohistochemistry study showed that TuJ1 shows discrete (1+) staining in the stroma more close to Bowman's membrane. E-Cadherin is poorly expressed at the atrophic area of the epithelium and expressed normally in the rest of the corneal epithelium. There’s no cell growth and differentiation showed by PCNA and TGFß1. There were a positive staining of MMP-9 (2+) in the epithelium and the subepithelial area. MMP-24 marker is present at ectasia areas of the epithelium and near the breakdown figures of the Bowmann membrane and disruption of laminin deposition.
Conclusions: :
Keratoconus cornea with the classic findings of light pathology express MMPs-9 and 24 but not TGFß1. This findings suggest active remodelation of the epithelial tissue with limited proliferation or differenciation of stromal keratocytes.
Keywords: keratoconus • microscopy: light/fluorescence/immunohistochemistry • cornea: stroma and keratocytes