[Dexamethasone effects of protein synthesis on organ-cultured human trabecular meshwork--autoradiographical,...

The effect of dexamethasone (DEX) on organ-cultured human trabecular meshwork (HTM) was evaluated autoradiographically, biochemically, and immunohistochemically. The tissues were obtained from 11 normal postmortem individual eyes, aged 15-84 years. In 2 individuals, 2-week treatment of cultured HTM with DEX (1 x 10(-4) M, 1 x 10(-5) M, 1 x 10(-6) M) induced the expression of 35S-methionine-labelled cell proteins of 40, 55, and 66 kD which were not present in HTM cultures with out DEX treatment. In electron microscopic autoradiography of the same cases, trabecular cells containing numerous intracytoplasmic vacuoles were seen and silver grains were found on microfibrils in the intracytoplasmic vacuoles. In addition, in immunoblot analysis of anti-alpha elastin of the same cases, a 72 kD band representing elastin was seen and DEX treatment showed stronger reactivity than the control. In immuno-electron microscopy of the same cases, elastin was localized on the surface of trabecular cells containing numerous intracytoplasmic vacuoles. In the remaining 9 individuals, there were no significant differences between control and DEX treatment. The alterations in the proteins/glycoproteins and elastin produced by DEX observed in organ-cultured HTM may play a role in the reduction in aqueous outflow facility observed clinically in steroid glaucoma.