Production of glycosaminoglycans by cell cultures of the trabecular meshwork of the primate eye

Abstract

Monolayer cultures derived from the isolated trabecular meshwork tissue of the eyes of three monkeys have been established as primary cultures (designated as TS and TI) and as regularly subcultivated cultures (designated as TI5) for time-periods ranging from 6 months to 3 years. These cells produce glycosaminoglycans which are secreted into the media. Sodium [ 35S]-sulfate or [ 14C]glucosamine were used as radioactive precursors for the study of glycosaminoglycan synthesis. As revealed by electrophoretic separation of the labeled glycosaminoglycans on cellulose acetate strips and by enzymatic characterization, TS- and TI-cultures incorporated the labeled glucosamine mainly (between 60 and 85%) in hyaluronic acid and chondroitin-4-sulfate (between 11 and 34%), while TI5-cultures incorporated glucosamine predominantly into hyaluronic acid (63%) and dermatan sulfate (31%). [ 35S]sulfate was mainly incorporated by TS- and TI-cells into chondroitin-4-sulfate and by TI5-cells into dermatan sulfate. Under the assumption that these glycosaminoglycans are also synthesized by the trabecular meshwork in situ, it is suggested that the gel-like properties of hyaluronic acid and the ion-binding capacity of the sulfated glycosaminoglycans might have a function in the filtering mechanism of the aqueous humor outflow.