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Abstract
PURPOSE: Corneal edema is a significant component of the various forms of herpes simplex virus type 1 (HSV-1)-induced stromal disease. Maintenance of corneal thickness, a reflection of corneal hydration, depends on a physical barrier formed by endothelial cell-cell junctions and by the activity of Na+/K(+)-ATPase pumps that regulate ion flux and thus influence water movement through this cell layer. These functions were measured in corneas with increased corneal thickness caused by HSV-1-induced stromal disease to determine their contribution to the pathogenesis of the edema. METHODS: Stromal disease with corneal edema was induced in rabbits by intrastromal injection of the RE strain of HSV-1. At various times after infection, during the development of and recovery from stromal disease, endothelial barrier function and Na+/K(+)-ATPase pump sites were measured in excised rabbit corneas. RESULTS: The endothelial permeability coefficient, Ktrans, for 14C-dextran, 3H-inulin, and 14C-mannitol, were not altered significantly during periods of maximal corneal edema and stromal disease. Endothelial Na+/K(+)-ATPase pump density, as measured by ouabain binding, showed a statistically significant (P < 0.05) decrease in HSV-1-infected corneas during peak edema compared to mock antigen-injected or uninjected control corneas. Pump density returned to baseline values by 24 days after infection, concurrent with the resolution of corneal edema. CONCLUSIONS: These results indicate that corneal endothelial barrier function was not altered in this form of HSV-1-induced stromal edema; however, pump density was reduced significantly.