Pheophorbide-Aによる胃癌培養細胞に対するNd-YAG Laser-PDTの基礎的検討

抄録

The capacity of pheophorbide-a (PpA) as a photosensitizing agent for photodynamic therapy of cancer was evaluated in vitro by human gastric cancer cells.
When the concentration of PpA in culture medium was 10, 100, 250μg/ml, intracellular concentration of PpA was 36.5, 153.5, 157.5μg/ml respectively.
Under the exposure of lamp (20 Watt, distance 40cm) for two hours, the optical density of MTT assay for cancer cells with a PpA concentration of 250μg/ml decreased to 8.1% against PpA free cells. In the dark room, it remained within 86.8% suggesting that PpA was very sensitive to light. Photodynamic therapy by administration of dye (100-250μg/ml) and Nd-YAG laser light irradiation with Q switch (1064nm, 200pps, mean power 1.5 Watt, duration 1, 3, 5min) after 2 hours incubation brought about a significant cell death. Lipid peroxide levels were elevated as increasing of laser irradiation time or the concentration of PpA.