The Influence of Stromal Contraction in a Wound Model System on Corneal Epithelial Stratification

PURPOSE. The healing process of some corneal wounds involves closure by stromal contraction and the renewal of the stratified epithelium. In wound gape injury such stromal contraction occurs with epithelial stratification. In previous in vitro studies of noncontracted and contracted corneal fibroblast-seeded collagen gels (FSCGs) it was shown that initiation of wound contraction by the myofibroblast phenotype (present within the wounded stroma) was dependent on vitronectin and/or fibronectin. This study considers one aspect of the epithelial‐ stromal interaction that occurs during wounding. The stratification of corneal epithelial cells on noncontracted and contracted corneal FSCGs was compared. METHODS. Dissociated bovine corneal epithelial cells were seeded on noncontracted and contracted corneal FSCGs, and these assemblies were cultured for 7 days. The epithelium that formed was evaluated using laser confocal microscopy and immunohistochemical markers directed against cytokeratin 3, desmoplakin I and II, integrin a-6 subunit, laminin, and collagen VII. The characteristics of the epithelium were compared with stromal carriers comprised of dissociated bovine corneal epithelial cells seeded on intact stroma and basement membrane (stromal carrier biopsies). RESULTS. The stratified epithelium that developed on contracted corneal fibroblast-seeded collagen gels was similar to that formed on stromal carriers, whereas nonstratified epithelium formed on noncontracted FSCGs. CONCLUSIONS. These studies showed that the contracted state of fibroblast-seeded gels enhanced the development of well-organized, stratified corneal epithelium. (Invest Ophthalmol Vis Sci. 2001;42:81‐ 89) M any cellular events occur during corneal wound healing to ensure that the tissue can resume its normal function in light refraction. When both the epithelium and the underlying stroma are wounded, epithelial cells and corneal fibroblasts (CFs) are directly involved in the repair process. In the wounded stromal tissue, CFs are activated and transform into the myofibroblast (MF) phenotype. 1,2 Previous studies suggest that the presence of CFs/MFs influence epithelial stratification. 3