Cellular photoablation to control postoperative fibrosis in filtration surgery: in vitro studies

The purpose of this study was to evaluate the feasibility of cellular photo ablation using fluorescence-generated photoreaction products as a method to control postoperative fibrosis in filtration surgery. The fluorescent prob e. 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl es ter (BCECF-AM) is a cell membrane permeable compound rendered membrane-impe rmeable and fluorescent upon cleavage by intracellular esterases. Human scl eral and Tenon's capsule fibroblasts were cultured and used as the target c ells. Uptake and retention of the probe were determined with a fluorescence multi-well plate reader. Fibroblasts with or without intracellular probe w ere irradiated under conditions of fluorescence microscopy with diffuse blu e light (450-490 nm, 1.68 x 10(2) mW m(2-1)). The viability of cells was ex amined by trypan blue exclusion and crystal violet test. To better mimic a wound healing process the effect of cellular photoablation was verified in artificial lesions produced in cultured monolayers loaded with different co ncentrations of the probe. Uptake and retention of BCECF-AM is dependent on ambient concentration. When incorporated the probe is lethal to those cell s exposed to the appropriate photoirradiation. Cells exposed to BCECF-AM (f or 45 min) at a concentration of approximately 10 mu M and irradiated for 1 min resulted in 100% cell death. Cellular photoablation in contrast to che motherapeutic agents acts only on the targeted cells. This method shall be pursued as an alternative therapy to control postoperative fibrosis in filt ration surgery. (C) 2000 Academic Press.