水溶性pheophorbide-aの実験脳腫瘍モデルにおける分布動態の検討

-特に腫瘍部と脳浮腫部の比較について-

抄録

This is the first report of perifocal brain edema levels of water-soluble pheophorbide-a (Ph-a-Na) comparing with experimental brain tumor levels.For this study,C-6 glioma was implanted into cerebrum of rats,and after about 2 weeks Tumors that grew into 5-7 mm in size and had perifocal brain edema were selected using Magnetic Resonance Imaging. Ph-a-Na levels of tumor region,edema region and normal brain region were analyzed by high-performance liquid chromatography (HPLC) at 4 and 12 hours following intravenous injection of Ph-a-Na.Tumor region level (P<0.05) and brain edema level (P<0.01) of Ph-a-Na at 4 hours were significantly different from normal brain levels of Ph-a-Na at 4 hours (Scheffe's method). At 4 hours after intravenous injection of Ph-a-Na, the tumor: normal brain ratio was 3.84, while the edema: normal brain ratio was 4.43. At 12 hours after intravenous injection of Ph-a-Na, each tissue levels of Ph-a-Na remarkably decreased from at 4 hours.This result indicates a rapid disappearance of Ph-a-Na from body.
These results indicate that at 4 hours after intravenous injection of Ph-a-Na, Ph-a-Na levels of tumor region and edema region are estimated as same on the whole, and much higher than that of normal brain region. This suggests that if photodynamic therapy ( PDT) using Ph-a-Na is applied to brain tumor which has perifocal edema,photochemical reaction which occured at edema region may be equal generally to tumor region.Some reports had been made about that perifacal edema may grow serious after PDT for brain tumor. The cause of this phenomenon may be led by similarity of concentration of photosensitizer between at edema region and at tumor region.