1987 Volume 78 Issue 4 Pages 572-578
The distribution of hematoporphyrin derivative (HPD) and photodynamic tumor destruction in which HPD is activated by an argon-dye laser light (630nm) have been investigated in rats beaming N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) induced bladder tumors.
HPD fluorescense was microscopically observed in the tumor cells and submucosal layer for a 7-day observation period after HPD I.V. injection. HPD fluorescence in the liver, spleen and kidney showed a tendency to reduce 2 to 4 days after HPD administration. A fluorescence emission spectrum with 2 bands at 627 and 693nm, compatible to that of HPD, was observed in the tumorous tissue 48 hours after HPD administration. No fluorescense spectrum was obtained in the normal bladder 48 hours after HPD administration. These findings suggested preferential uptake or accumulation of HPD in the tumor tissue.
Laser irradiation 48 hours after HPD injection produced definitive tumor destruction when the light intensities were increased from 100 to 500mW/cm2. No tumoricidal effect was seen in the tumors treated with either HPD or light alone as controls. An additional study of temperature rise during the laser irradiation using a bladder model containing 2ml saline solution showed no hyperthermia. The tumor destruction was proved to be resulted from photodynamic effects of HPD activated by the laser light without hyperthermia.
