A comparative study of extracellular sulfated glycosaminoglycans synthesized by rabbit corneal fibroblasts in organ and confluent cultures

Abstract

The extracellular sulfated glycosaminoglycans synthesized by explants of rabbit cornea and sclera, and by confluent cultures of corneal fibroblasts after incubation in medium containing 35S-sulfate were compared. The glycosaminoglycans isolated from corneal explants differed considerably from those obtained from confluent corneal fibroblast cultures and scleral explants. Only the corneal explants secreted into the nutrient medium a population of enzyme-resistant 35S-sulfate-labeled glycosaminoglycan that eluted from Dowex 1-X2 (Cl-) at a 3 M sodium chloride concentration, and which was resistant to testicular hyaluronidase, chondroitinase ABC, and nitrous acid degradation. With time, corneal explants gradually synthesized less of this fraction with these attributes of keratosulfate. If the corneal epithelium and endothelium remained on the corneal explants the total incorporated 35S-sulfate was approximately double that obtained when the cornea was striped of these cells.