Correlation of corneal endothelial pump site density, barrier function, and morphology in wound repair

After transcorneal freezing, physiologic function (pump and barrier) of the regenerating rabbit corneal endothelium was evaluated and compared with the morphologic differentiation that occurs during wound healing. Endothelial pump function was investigated utilizing the specific binding of tritiated ouabain to endothelial Na+/K+ ATPase (pump sites); the permeabilities of isolated de-epithelialized corneas to labeled inulin and dextran were measured to determine endothelial barrier function. Endothelial recovery after transcorneal freezing can be described as a three-stage process. Stage one is characterized by the establishment of an initial coverage of the wound by pleomorphic spindle-shaped cells which form a functional but incomplete barrier and minimal pump site density. In stage two, the cells assume a flattened configuration consisting of irregular polygons and establish nearly normal pump capacity. In stage three, a significant remodeling of the monolayer continues despite the layer's early physiologic recovery.