RRC ID 69435
Author Kawauchi S, Sato S, Morimoto Y, Kikuchi M.
Title Intracellular kinetics of ATX-S10.Na(II) and its correlation with photochemical reaction dynamics during a pulsed photosensitization process: effect of pulse repetition rate.
Journal J Biomed Opt
Abstract Although photodynamic therapy with pulsed light excitation has interesting characteristics, its photosensitization mechanism has not been fully elucidated. In this study, we showed that the intracellular kinetics of ATX-S10.Na(II), a lysosomal sensitizer, was closely related to photochemical reaction dynamics during photodynamic treatment of A549 cells with nanosecond pulsed light. Fluorescence microscopy revealed that at high frequencies of 10 and 30 Hz the sensitizer initially localized mainly in lysosomes but that it started to be redistributed to the cytosol in certain ranges of radiant exposures. These ranges were found to coincide with a regime of fluorescence degradation with limited oxygen consumption. On the other hand, at 5 Hz, there was no such a discontinuous behavior in the sensitizer redistribution characteristics throughout the period of irradiation; this was consistent with the fact that no reaction switching was observed. Two possible reasons for the appearance of the regime with limited oxygen consumption are discussed: participation of an oxygen-independent reaction and change in the microenvironment for the sensitizer caused by lysosomal photodamage. The pulse frequency-dependent intracellular kinetics of the sensitizer also explains our previous results showing higher cytotoxicity at 5 Hz than at 10 and 30 Hz.
Volume 11(1)
Pages 014005
Published 2006-1-1
DOI 10.1117/1.2160387
PMID 16526882
MeSH Adenocarcinoma / drug therapy Adenocarcinoma / metabolism* Cell Line, Tumor Dose-Response Relationship, Radiation Humans Kinetics Lasers Light Metabolic Clearance Rate / radiation effects Photochemistry / methods Photochemotherapy / methods Photosensitizing Agents / administration & dosage Photosensitizing Agents / pharmacokinetics* Porphyrins / administration & dosage Porphyrins / pharmacokinetics* Subcellular Fractions / metabolism* Subcellular Fractions / radiation effects*
IF 2.785
Human and Animal Cells A549(RCB0098)