Delayed oxidative photodamage induced by photodynamic therapy.
Apoptotic DNA fragmentation was observed 60 min after photodynamic therapy of murine leukemia cells in culture, using either of two photosensitizers with predominantly lysosomal targets. When the radical scavengers trolox or alpha-tocopherol succinate were present during irradiation, the subsequent appearance of apoptotic cells was prevented, as was phototoxicity. Addition of either scavenger during the 60 min after irradiation provided only partial protection from apoptosis and phototoxicity; this protection was abolished if the addition was delayed for 10 min. These results are consistent with a model whereby long-persisting photoproducts continue the initiation of apoptosis for approximately 10 min after irradiation has ceased.
Kessel
D
D
Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA. DHKESSEL@med.wayne.edu
Luo
Y
Y
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053938:DNA Fragmentation; D007939:Leukemia L1210 / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D051379:Mice; D010084:Oxidation-Reduction; D010777:Photochemistry; D010778:Photochemotherapy; D014407:Tumor Cells, Cultured