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Photodynamic effects on human and chicken erythrocytes studied with microirradiation and confocal laser scanning microscopy
Author(s) -
König Karsten,
Kimel Sol,
Berns Michael W.
Publication year - 1996
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/(sici)1096-9101(1996)19:3<284::aid-lsm4>3.0.co;2-o
Subject(s) - hemolysis , photodynamic therapy , fluorescence , fluorescence microscope , methylene blue , confocal , red blood cell , lysis , biophysics , chemistry , confocal microscopy , confocal laser scanning microscopy , microscopy , protoporphyrin ix , pathology , biology , microbiology and biotechnology , medicine , biochemistry , immunology , optics , physics , organic chemistry , photocatalysis , catalysis
Background and Objective Photodynamic therapy (PDT) of cancers is associated with the destruction of the microvasculature supplying the tumor. The study elucidates the role of red blood cells in PDT‐induced vascular injury. Study Design/Materials and Methods Intracellular accumulation of several photosensitizers in human (non‐nucleated) and chicken (nucleated) erythrocytes, as well as photodynamic induced hemolysis were studied using 488 nm laser microirradiation (15 μW) and confocal laser scanning fluorescence microscopy. Results Cells incubated with anionic hydrophilic compounds TPPS 4 and Pd‐TPPS 4 exhibited no fluorescence before irradiation, but developed strong and sustained fluorescence in the cellular and nuclear membranes following photoinduced membrane damage. In contrast, microirradiation of Photofrin‐incubated erythrocytes showed instantaneous fluorescence which decreased due to photodegradation. For the cationic hydrophilic dye methylene blue, significant fluorescence was detected only in the nucleus. Following ALA incubation, large intercellular differences were observed in fluorescence in the red spectral region. Photofrin induced the most efficient hemolysis. Higher radiant exposures were required for lysis of nucleated rather than of non‐nucleated red blood cells, except in the case of methylene blue. Conclusion Laser microbeams were used, for the first time, to study photodynamic cell damage. Erythrocytes were shown to be primary targets in PDT. Damage to red blood cells could be responsible for hemostasis in the vascular bed of a tumor, which was reported by many groups. © 1996 Wiley‐Liss, Inc.