Premium
ENHANCED TUMOUR SELECTIVITY OF PHOTODYNAMIC THERAPY IN THE RAT COLON USING A RADIOPROTECTIVE AGENT
Author(s) -
Bedwell J.,
Chatlani P. T.,
MacRobert A. J.,
Roberts J. E.,
Barr H.,
Dillon J.,
Bown S. G.
Publication year - 1991
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1991.tb09888.x
Subject(s) - photodynamic therapy , photobleaching , phototoxicity , chemistry , necrosis , photosensitizer , pharmacology , selectivity , in vivo , fluorescence , cancer research , pathology , medicine , in vitro , photochemistry , biochemistry , biology , organic chemistry , quantum mechanics , catalysis , physics , microbiology and biotechnology
— —Radioprotective agents have been found to protect normal tissues during photodynamic therapy (PDT). We have investigated a phosphorylated thiol protectant WR‐77913 (W7) with the photosensitizer aluminium sulphonated phthalocyanine (AlSPc). We compared the effects of PDT on normal and tumour tissue in the rat colon, with and without this protectant. In normal colon no necrosis was seen in sites treated after administration of the W7. Necrosis of mean diameter 4.2 mm was seen in those given the protectant after light exposure. At tumour sites the area of necrosis was similar after light exposure before and after the administration of the protective agent. These results suggest a possible role for W7 in enhancement of selectivity of PDT action. Several mechanisms of protection against porphyrin phototoxicity by these drugs have been proposed, including acceleration of photobleaching. We used fluorescence to detect AlSPc in strips of rat colon before and after laser treatment, with and without W7. However, a primary role for the photobleaching of AlSPc as the mechanism for the protection shown is not supported by these observations.