Secondary aqueous humor stimulates the proliferation of cultured bovine corneal endothelial cells.

Secondary aqueous humor (2 degrees AH) is known to contain elevated levels of serum macromolecules and has been shown to stimulate the proliferation of lens epithelial cells both in vivo and in vitro as well as corneal endothelial cells in vitro. The purpose of this study was to characterize the response of bovine corneal endothelial cells to 2 degrees AH from rabbits and to compare the effect when the cells were grown on plastic dishes covered with an extracellular matrix or on plastic alone. The addition of varying amounts of 2 degrees AH protein (0.1 to 10 mg/ml) to bovine corneal endothelial cells (cultured in MEM plus 1% serum) resulted in a dose dependent proliferative response as measured by the incorporation of 3H-thymidine into DNA. Except for a 2-hr lag phase, the proliferative response increased with increasing time of exposure (6-18 hrs) of the cells to 2 degrees AH containing a constant amount (2.0 mg/ml) of protein. The generation time and final density of the cells, but not the plating efficiency, was significantly greater when the cells were grown in the presence of 2 degrees AH protein on an extracellular matrix rather than plastic alone. Selective adsorption of prostaglandins and aromatic compounds from 2 degrees AH reduced its ability to produce a proliferative response to control levels. These results indicate that 2 degrees AH can alter or regulate events in the cell cycle of corneal endothelial cells. The responsible factor(s) could be involved in control of cellular regeneration in the eye following injury.