Abstract
The phototoxic effects of acridine orange (AO) or hematoporphyrin derivative (HpD) with dye laser irradi-ation on Walker carcinosarcoma 256 tumors and human gastric cancer cells were studied. Observations were made by phase-contrast microscopy and electron microscopy.
Tumor-bearing rats were injected i. p. with 40mg/Kg of AO 2hr before irradiation. Then the tumors were exposed to the argon laser at 488nm at an intensity of 15mW/cm2 for 20min. Irradiation caused complete or partial tumor necrosis with sparing of surrounding mucosa. No marked temperature rise was detected during irradiation.
Human gastric cancer cells were obtained by biopsy. They were incubated in serum containing 36uM of AO or 0.9mM of HpD, and were exposed to dye laser (488nm for AO or 630nm for HpD) at the same intensity as above. Cancer cells were immediately damaged by irradiation.
The difference of phototoxic degeneration process of tumor cells between AO and HpD was discussed and the formation of singlet oxygen was suggested in these systems.
