Altered matrilin-2 and tenascin-C expression in corneal diseases with reduced transparency

Purpose: The purpose of this study is to examine the expression of tenascin-C and matrilin-2 in three different disorders, which frequently require corneal transplantation. These pathological conditions include bullous keratopathy (BK), Fuchs' endothelial corneal dystrophy (FECD) and corneal scaring in herpetic keratitis. Materials and methods: Histological sections of corneal buttons removed during keratoplasty were analyzed in BK (n = 20), FECD (n = 9), herpetic keratitis (n = 12), and cadaveric control (n = 10) groups by light microscopy following chromogenic immunohistochemistry. The sections were evaluated by three investigators and semiquantitative scoring (0 to 3+) was applied according to standardized methods at 400× magnification. Each layer of the cornea was investigated, moreover, the stroma was subdivided into subepithelial, middle, and the pre-Descemet areas for more detailed analysis. Results: Excessive epithelial and stromal expression of tenascin-C was identified in all investigated conditions, the results being most pronounced in the pre- Descemet layer. Regarding matrilin- 2, when examined in BK, there was increased labelling intensity in the epithelium (p < 0.001) and stromal layers (p < 0.05), and a decrease in the endothelium (p < 0.001). In the other investigated conditions only a low degree of stromal localization (p < 0.05) of matrilin-2 was detected. Conclusion: The expression of tenascin- C and matrilin-2 differs when examined in various corneal pathologies resulting in opacification. Both molecules seem to be involved in the regeneration and wound healing of the corneal matrix in these diseases.