Damage and repair of molecular targets of human skin fibroblasts irradiated with fluorescent light (380-420 nm).

Human fibroblast cultures irradiated in phosphate-buffered saline are severely damaged by high doses of fluorescent light (380-420 nm), which have a direct effect on such cells. At a dose of 400 kJ/m2, the colony-forming capacity is decreased by up to 50%. SH groups in the membrane and cytosol are destroyed by irradiation, as determined with 6-6'-dithiodinicotinic acid (DTNA) and 5,5-dithiobis-2-nitrobenzoic acid (DTNB). Another molecular target that is severely damaged is tryptophan (up to 25%). However, peroxidation products of unsaturated fatty acids were not observed in our experiments. Survival improved and molecular damage was repaired to some extent by exposing the cells to optimal growth conditions immediately after irradiation.