Koarova, H., R. Kubinek, R. Lenobel, M. Bancirova, M. Strnad, D. Jirova, K. Kejlova and J. Lasousky. Alternative In Vitro Approaches to Testing of Photosensitisers. ATLA 27: 300. 1999.

Photochemically induced cell death during photodynamic treatment of local tumours requires three components to be present: a photosensitiser, oxygen and laser irradiation with the wavelength corresponding to the absorption maximum of the photosensitizing chemical. A new promising generation of photosensitisers, a group of specific dyes, CIAIPcS2 and ZnPcS2 phthalocyanines, was used. As a source of radiation, a semiconductor laser (power 50 mW, l = 670 nm) was employed. Within the past decade, alternative approaches to phototoxicity testing have been evaluated for methodological and ethical reasons in order to replace routine testing on animals. A standard testing system using B16 pigmented melanoma, MCF7 (mammary carcinoma), HOS standard testing system using B16 pigmented melanoma, MCF7 (mammary carcinoma), HOS (osteosarcoma), Hs913T (fibrosarcoma) and NIH/3T3 (mouse fibroblasts) cells have been chosen to detect in vitro cytotoxicity and phototoxicity. Morphological changes in cell cultures have been evaluated using an inversion fluorescent microscope Olympus IX 70. The viability of cells was determined by means of molecular probes for fluorescence microscopy (double-staining with calcein AM and ethidium homodimer). The changes in cell viability and morphology in relation to phtalocyanine concentrations and irradiation doses were proved. CIAIPcS2 and ZnPcS2 phtalocyanines showed phototoxicity under the test conditions. According to our results, ZnPcS2 seems to be more phototoxic than CIAIPcS2. MCF7 cells were the most sensitive to photodynamic damage. All the cellular substrates used are suitable for detection of phototoxicity caused by laser-irradiation photosensitisers.