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CHANGES IN TUMOR INTERSTITIAL PRESSURE INDUCED BY PHOTODYNAMIC THERAPY
Author(s) -
Fingar Victor H.,
Wieman T. Jeffery ,
Doak Karola Weber
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.tb09890.x
Subject(s) - ketanserin , chemistry , antagonist , photodynamic therapy , endocrinology , medicine , serotonin , 5 ht receptor , receptor , biochemistry , organic chemistry
— —This study has examined the changes in tumor interstitial pressure exhibited during and after photodynamic therapy (PDT). The kinetics of these changes are marked by an initial decrease, followed by a rapid rise in tumor interstitial pressure. We have also employed two inhibitory agents to evaluate the different components of the pressure curve. Specially designed pressure chambers were seeded with chondrosarcoma and implanted subcutaneously in rats. Animals were injected with 0–50 mg/kg Photofrin II (i.v.) 7 days post‐implantation and tumors were exposed to 0–540 J/cm 2 630 nm 24 h later. Interstitial pressure was monitored via a transducer connected to the implanted chamber. Additional groups of animals were injected with either indomethacin (an inhibitor of thromboxane synthesis) or Ketanserin (a serotonin antagonist) before light treatment. Porphyrin doses of 10 mg/kg and above (135 J/cm 2 ), or light doses of 135 J/cm 2 and above (25 mg/kg Photofrin II) were effective in modifying interstitial pressure. Porphyrin doses greater than 25 mg/kg, or light doses greater than 270 J/cm 2 produced no further increases in interstitial pressure. Animals given indomethacin (10 mg/kg i.p.) exhibited the initial decrease in pressure during light treatment, but showed no increase past baseline levels. Animals given Ketanserin (10 mg/kg i.p.) demonstrated no decrease in pressure during PDT, but showed the same elevations in pressure as controls. This suggests that two independent mechanisms account for the different components of the pressure curve, and that serotonin release may occur during PDT.