Acta Med. 2004, 47: 327-329

Assessment of Cellular Damage by Comet Assay After Photodynamic Therapy in vitro

Jaroslav Macečeka, Hana Kolářováa, Jitka Psotováb, Robert Bajgara, Martin Hufa, Pavla Nevřelováa, Marek Tomečkaa, Jiří Mosingerc

aPalacky University in Olomouc, Faculty of Medicine, Department of Medical Biophysics, Olomouc, Czech Republic
bPalacky University in Olomouc, Faculty of Medicine, Department of Medical Chemistry, Olomouc, Czech Republic
cCharles University in Prague, Faculty of Science, Department of Inorganic Chemistry, Prague, Czech Republic

The aim of this study was analysis of DNA damage in the cell line of the human melanoma G361 after photodynamic therapy (PDT) by comet assay. Photodynamic therapy is based on cytotoxic action of sensitizers (10 µM ZnTPPS4 fixed into 1 mM cyclodextrin hpβCD) and light with a suitable wavelength. Single-cell gel electrophoresis (SCGE, comet assay) is a rapid and sensitive method for detecting DNA strand breaks at the level of single cells. Great amount of DNA damage was detected with the dose of irradiation of 0.1; 0.5 J and 2.5 Only radiation dose of visible light in the presence of sensitizers can induce DNA breaks of tumour cells. Cells with DNA damage appear as fluorescent comets with tails of DNA fragmentation. In contrast, cells with undamage DNA appear as round spots, because their intact DNA does not migrate out of the cell.


This work was supported by the grant project of the Grant agency of Czech Republic No. 203/02/1483 and Ministry of Education MSM No. 153100008.


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