Effect of chondroitin sulfate on the endothelium in corneal storage

The scope of this study includes investigations on uptake of dextran and chondroitin sulfate in human donor corneas, and effects of chondroitin sulfate on adhesion and growth of rabbit and cat corneal endothelial cells. Fibronectin and dextran sulfate served as controls. Nuclear magnetic resonance spectroscopy revealed no detectable osmotic agents in the corneas stored in either Dexsol or Optisol at 4 degrees C for 6 days. The study showed that chondroitin sulfate enhanced cell adhesion marginally at 2.5%, but >40% at 0.5%, comparable to that of 10 mu g/ml fibronectin, whereas 2% dextran sulfate abolished approximately 70% of cell adhesion capability. In cultures with fibronectin present, the duration for cells to reach confluence was extended from 1.75 to 3 days. Chondroitin sulfate (2%) elicited no apparent cytotoxic effect, with cells becoming polygonal and reaching confluence in approximately 9 days. Cell growth was retarded by 2% dextran sulfate, with signs of senescence on day 3 and clear evidence of cell degeneration on day 9. The cells did not survive without serum in cultures, especially at 36 degrees C. These findings suggest that corneal deterioration probably is linked primarily to serum-free storage conditions, not uptake of osmotic agents in the cornea. The highly negatively charged sulfate group, however, may have rendered chondroitin sulfate less effective as an additive.