Comparative cytotoxic and antiproliferative profile of methotrexate and fluorouracil on different ocular cells

To analyse the cytotoxic and antiproliferative effect of methotrexate (MTX) and fluorouracil (5-FU) in vitro on fibroblasts, retinal pigment epithelial (RPE) and photoreceptor cells as an adjunct for reducing the incidence of proliferative vitreoretinopathy (PVR) after rhegmatogenous retinal detachment surgery.

Methotrexate and 5-FU were dissolved separately in balanced salt solution (BSS) with concentrations ranging from 0-8000 µg/ml and 0-4000 µg/ml, respectively. All solutions were analysed in terms of pH and osmolarity and applied for 1 h to fibroblasts (BJ), RPE (ARPE-19) and photoreceptor (661W) cell lines adherently cultivated in 96-well cell culture plates (10 000 cells/well). 24 h after incubation, the proliferative (BrdU), metabolic (CellTiter-Glo) and apoptotic (Caspase 3/7) activity of the cells were examined in vitro.

5-FU had an antiproliferative effect on BJ and ARPE-19 cells starting from low concentrations (2 µg/ml). However, the viability of 661W cells decreased and apoptosis was induced with increasing 5-FU concentration. In contrast, MTX up to a concentration of 266 µg/ml did neither result in a significant loss of viability nor in increased caspase 3/7 activity of BJ, ARPE-19 and 661W cells and inhibited the proliferation of ARPE-19 already at low concentrations starting from 8 µg/ml.

Methotrexate dissolved in BSS is biocompatible up to a concentration of 266 µg/ml and may act as an intraoperative rinse solution to inhibit RPE proliferation in PVR-diseased eyes. Contrary, the use of 5-FU within the posterior segment of the eye is limited by its cell-damaging effect on photoreceptor cells.