Characterization of extracellular matrix remodelling enzymes in the sclera after collagen cross linking (SXL)

Purpose High myopia is characterised by excessive eye growth and mechanically weakened, thinned and stretched scleral tissue. Enhanced chemical cross linking of collagen fibrils in the sclera (SXL) is a promising therapeutic approach to stiffen the sclera and to prevent eye globe elongation. Therefore, it is important to understand the role of collagen fibril producing fibroblasts and the extracellular matrix remodelling enzymes in normal and myopic eyes and after SXL treatment. Methods We examined scleral tissue of normal rabbit eyes and after SXL treatment by means of histology and electron microscopy. We characterised expression profiles of cellular markers (e.g. Vimentin) and of relevant enzymes (e.g. MMPs) by means of RT-PCR analysis and immunohistochemistry in cell cultures from human and rabbit scleral tissue. Results We observed altered scleral collagen fibril profiles and activated scleral fibroblasts - signs of remodelling processes after SXL treatment. Fibroblasts are capable to produce and secrete collagen and different matrix-degrading and regulatory enzymes (e.g. MMP1-3 and 9; TIMP1-4; LOX). Conclusion Significant remodelling processes were induced after SXL treatment and the role of each specific contributor/enzyme has to be determined for an efficient SXL treatment. increases scleral stiffness. We want to investigate the influence of relevant enzymes on remodelling processes after SXL to optimize the new and promising therapeutic approach.