Endothelial and Stromal Cells

Confluent monolayer cultures of rabbit corneal endothelial and stromal cells were incubated independently with [35S]sulphate and [3H]glucosamine for 3 days. After incubation, labelled glycosaminoglycans were isolated from the growth medium and from a cellular fraction. These glycosaminoglycans were further characterized by DEAEcellulose column chromatography and by sequential treatment with various glycosaminoglycan-degrading enzymes. Both endothelial and stromal cultures synthesized hyaluronic acid as the principal product. The cell fraction from the stromal cultures, however, had significantly less hyaluronic acid than that from the endothelial cultures. In addition, both types of cells synthesized a variety ofsulphated glycosaminoglycans. The relative amounts of each sulphated glycosaminoglycan in the two cell lines were similar, with chondroitin 4-sulphate, chondroitin 6-sulphate and dermatan sulphate as the major components. Heparan sulphate was present in smaller amounts. Keratan sulphate was also identified, but only in very small amounts (1-3 %). The presence of dermatan sulphate and the high content of hyaluronic acid are similar to the pattern of glycosaminoglycans seen in regenerating or developing tissues, including cornea.