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Suppression of Delayed‐type Hypersensitivity and Hemolysis Induced by Previously Photooxidized Psoralen: Effect of Fluence Rate and Psoralen Concentration
Author(s) -
Kyagova Alia A.,
Zhuravel Natalia N.,
Malakhov Mikhail V.,
Lysenko Eugene P.,
Adam Waldemar,
SahaMoller Chantu R.,
Potapenko Alexander Ya.
Publication year - 1997
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.1751-1097.1997.tb01912.x
Subject(s) - psoralen , chemistry , hemolysis , biophysics , medicine , biochemistry , biology , dna
— The kinetics of the formation of biologically active psoralen photooxidation (POP) products were analyzed by the biological effects produced. Effects of the UV light fluence rate and psoralen concentration during the preir‐radiation were investigated to assess the yield of POP products, which were active in vivo (inducing suppression of delayed‐type hypersensitivity [DTH] reaction to sheep red blood cells) and in vitro (altering the human erythrocyte membrane permeability). It was shown that the reciprocity law of the irradiation fluence rate and time was not valid in the case of POP‐induced hemolysis and DTH suppression. Immunosuppressive POP products were more efficiently formed at low fluence rate (20.8 W/m 2 ), whereas POP hemolysins were more efficiently produced at a high fluence rate (180 W/m 2 ) of UV light. The yield of immunosuppressive POP products was enhanced in dilute psoralen solutions, while the POP hemolysins yield increased with increasing psoralen concentration. A kinetic scheme for psoralen photoproduct formation was proposed. Kinetic analysis showed that a labile intermediate was produced as the result of excitation of psoralen. This intermediate was either converted to a stable immunosuppressive POP product, or two intermediates combined to form a POP hemolysin. It is proposed that PUVA therapy conditions are more favorable for the formation of immunosuppressive rather than membrane‐damaging psoralen photooxidation products.