Sodium and bicarbonate fluxes in regenerating rabbit corneal endothelium

Rabbit corneal endothelia were subjected to a cryoinjury (-70 degrees C for 15 sec) and sodium and bicarbonate fluxes were determined at various times after induction of the endothelial destruction. A complete monolayer of cells was present by 4 days that consisted of large cells that underwent division over the next 16 days. Unidirectional sodium fluxes were unaltered by the transformation from large to normal sized hexagonal cells. Unidirectional bicarbonate fluxes showed an increase in Jendostr coupled with a decrease in the net Jstrendo flux. As the cells became smaller these bicarbonate fluxes returned to normal values. The data indicate that the cell margin/cell size ratio is not related to the flux rates, thus the paracellular pathway increase with healing is not related to the passage of either sodium or bicarbonate. Secondly, the data indicate separate effects on both sodium and bicarbonate, suggesting that transendothelial movement of the ions can be separated and that they are not necessarily linked in passage across the endothelium.