Abstract
Purpose: :
Intravitreal injection of triamcinolone acetonide (TA), a corticosteroid, has recently been shown to be effective for treating exudative age–related macular degeneration (AMD) and macular edema. Our previous work indicated that intravitreal TA is safe for managing diabetic patients with macular edema. But we have also shown toxic effects of TA againg RPE19 and SVG cells in culture. The present study aims to show the cytotoxic effect of TA on human cultured trabecular meshwork (TM) cells.
Methods: :
TA (0.1 mg/ml, 1 mg/ml) or the vehicle (benzyl alcohol, 0.0025%, 0.025%) was added to the TM–23 cell cultures on day 0 and then subsequently for 1, 3, 5 days. The amount of cell proliferations with or without TA treatment was performed using 3–(4,5–dimethylthiazol–2–yl)–2,5–diphenylterazolium bromide (MTT) assay. All samples were read in triplicate (n = 4 in all cases). By quantitative real–time PCR, the expression levels of c–fos, c–jun, caspase–3, c–myc, and p53 were determined after TA treatments at 0min, 10min, 20min, 30min, 50min, 80min, 2hr, 12hr, 24hr and 48hr. Data were analyzed with paired t–tests.
Results: :
Both concentrations of TA caused significant reduction in the number of TM cells as early as day 1 and across 5 days of the treatment period. c–jun expression was significantly elevated after 12hrs on 0.1 mg/ml TA whereas a significantly increased c–fos expression was detected at 24hrs for 1 mg/ml TA. As for p53, c–myc and caspase3, significant increases were observed after 12hr at both TA concentrations.
Conclusions: :
Our results showed that TA was cytotoxic to TM cells in culture and the presence of TA caused apoptotic cell death. The effects were associated with TA concentrations and duration of TA treatments.
Keywords: trabecular meshwork • stress response • apoptosis/cell death