METHODOLOGY FOR DEMONSTRATING AND MEASURING THE PHOTOCYTOTOXICITY OF FLUORANTHENE TO FISH CELLS IN CULTURE

Methodology was developed for quantifying the photocytotoxicity of flu oranthene to a gill cell line from rainbow trout for future use in scr eening polycyclic aromatic hydrocarbons for their relative photocytoto xicity to fish. Solubilization in a modified culture medium was achiev ed with and without foetal bovine serum (FBS) and with and without dim ethyl sulfoxide (DMSO). FBS caused most of the fluoranthene to remain in solution and blocked photocytotoxicity if present during UV irradia tion. DMSO had little effect on fluoranthene distribution in cell cult ures but caused cells to be slightly more sensitive to the phototoxici ty of fluoranthene. The indicator dyes alamar BlueTM and 5-carboxyfluo rescein diacetate acetoxymethyl ester were used to quantify cytotoxici ty in two different ways-singly in two separate assays, and mixed toge ther in a novel single assay, which saved time and material. With UV i rradiation for 2 hr at a photon fluence rate of either 1.4 mu mol UV-B /m(2)/sec (UV-A:UV-B, 1.5) or 1.1 mu mol UV-B/m(2)/sec (UV-A:UV-B, 9.7 ), both dyes indicated increasing loss of viability with increasing do ses of fluoranthene. EC, values ranged from 18 to 44 ng/ml (89-217 nM) , with the alamar Blue assay being slightly more sensitive. (C) 1997 E lsevier Science Ltd.