Effects of varying 5-fluorouracil exposure duration on Tenon's capsule fibroblasts

Purpose: 5-Fluorouracil (5-FU) is used intraoperatively to improve the success of trabeculectomy. Common practice is a 5-min application of 5-FU delivered via a Weck Cel sponge. The aim of this study was to determine if shorter exposure times were as effective in inhibiting Tenon's capsule fibroblast proliferation. Methods: Samples of Tenon's capsules, obtained from young patients undergoing strabismus surgery, were immersed in vitro in 5-FU (50 mg/mL) for periods ranging from 1 to 10 min. Control samples were exposed either to growth medium (M199) or 5-FU vehicle alone. Explants were cultured for up to 7 days and analysed for cell density, cell viability using fluoroprobe detection, and cell proliferation determined by proliferating cell nuclear antigen (PCNA)-staining. Results: Exposure to 5-FU for 1 and 5 min resulted in a similar and significant inhibition of the culture-induced increase in stromal cell density (P < 0.01), a significant reduction in the percentage of viable cells (P < 0.02), and reduced PCNA indices, compared with controls. Exposure times of 3 and 10 min produced similar results. Conclusions: In vitro, under conditions of organ culture, a 1-min exposure to 5-FU had a significant antiproliferative effect on fibroblasts of Tenon's capsule, and was similar to 5 min of exposure. Optimal intraoperative 5-FU exposure time may be as little as 1 minute.