Effects of ascorbic acid on trabecular meshwork cells in culture

We examined the effects of ascorbic acid on trabecular meshwork cells in culture. Bovine trabecular meshwork cells were plated for 6 days and were exposed to media containing either no ascorbic acid or ascorbic acid in the following concentrations for 24 hr: 50-, 100-, 500-, and 750 micrograms ml-1. Fresh media were then added and incubation was continued for an additional 24 hr. The cell number was subsequently determined for the effects of the various concentrations of ascorbic acid on cell growth. In a parallel experiment, cells were labeled with [35S] sulfate (50 microCi ml-1) and [3H]glucosamine (15 microCi ml-1) for 24 hr with or without ascorbic acid for glycosaminoglycan studies. Results indicated that ascorbic acid stimulated the trabecular cell growth in culture at concentrations of 50-, 100-, and 250 micrograms ml-1. However, at 750 micrograms ml-1, cell growth was inhibited. In addition, cells exposed to 100 micrograms ml-1 of ascorbic acid demonstrated increased incorporation of [3H]glucosamine and [35S]sulfate; enhancement of incorporation of [35S]sulfate was also noted at 250 micrograms ml-1. Incorporation of labels was otherwise either unchanged or retarded at other concentrations. These data suggest that the ascorbic acid level in the aqueous humour may influence trabecular meshwork cell metabolism.