Biosynthetic responses of the rabbit cornea to a keratectomy wound.

Following a corneal wound involving removal of the epithelium and basement membrane, the epithelium must migrate across bare stroma. To examine the effect of the removal of the basement membrane on epithelial migration and on protein and glycoprotein synthesis in both the epithelium and stroma, we performed superficial keratectomies on rabbits and allowed the corneas to heal in organ culture. We then analyzed the following parameters: (1) rate of epithelial wound closure; (2) proteins synthesized during epithelial wound closure in both the epithelium and stroma using SDS-PAGE; and (3) presence of fibronectin in the epithelium and stroma using immunodot blots and immunofluorescence. We found that: (1) a 7 mm keratectomy wound heals in 66 hr with a maximal rate of epithelial migration of 0.83 mm2/hr; (2) four proteins, 400+K, 220K, 70K, and 58K, are present in the epithelium migrating to close the wound that are not seen in the control epithelium; (3) a 220K band is seen in the wounded stroma but not in control stroma; and (4) fibronectin represents 2% of the total protein in the stroma 66 hr post-keratectomy but less than 0.02% in wounded epithelium, unwounded epithelium, and unwounded stroma.

Con A- and WGA-binding glycoproteins of stationary and migratory corneal epithelium.

When stratified corneal rat epithelium becomes migratory in response to a wound, an increase in binding by the lectins concanavalin A (Con A) and wheat germ agglutinin (WGA) is seen. These lectins bind the membranes of the cells of the leading edge of the migrating sheet more intensely than normal epithelium and epithelium behind the leading edge, suggesting a change in cell surface properties during migration. In the present study, analysis of cell surface proteins using lactoperoxidase-catalyzed iodination followed by SDS-PAGE indicates the appearance of a 70 K protein in epithelium migrating to cover a wound. Con A-affinity chromatography shows that two bands, 70 K and 155 K, increase 4.0- and 2.9-fold, respectively, in epithelium that is migrating. WGA-binding glycoproteins increased 1.61-fold following wounding with the major band present at 155 K in SDS-PAGE. The data suggest that these glycoproteins are responsible for the increase in Con A and WGA binding to cell membranes in migratory corneal epithelium.