31P-Magnetic Resonance Spectroscopyによる尿路性器癌の放射線療法および化学療法の効果に関する実験的研究

Abstract

1)31P-MRSのスペクトルは, 増殖初期では高いレベルのPCr, ATP, PMEを認め, 増殖に伴いPCrは低下し, Piは増加した。2)増殖抑制効果は放射線照射群が最もすぐれ, ついでCDDP投与群であった。VP-16投与群では認められなかった。3)放射線照射群ではPCrが高く, Piが低い増殖初期のパターンが照射後24時間から約2週間維持された。組織学的変化は, 正常分裂像の減少, 核の腫大, 細胞質内空胞の出現などがおもなものであった。4)明らかな増殖抑制効果や組織学的変化を認めなかったCDDP, VP-16群ではスペクトルの変化は放射線照射群に比べて軽微であったが, Piの上昇, PCr/Pi比の減少は対照群に比較して軽度であった

The effects of local irradiation and intraperitoneal injection of cisplatinum (CDDP) and VP-16 were examined in the sequential 31P magnetic resonance spectroscopy (MRS) in testicular cancer (TC-1) and bladder tumor (BT-8) of human origin, serially transplanted in nude mice. In the early phase of tumor growth, high-energy phosphate metabolites such as phosphocreatinine (PCr), adenosine triphosphate (ATP) and phosphomonoester (PME) were detected in both grafted tumors. However, the relative value of inorganic phosphate (Pi) to PCr increased with the growth of the tumor. Irradiation had the most pronounced effect to inhibit growth, followed by CDDP in both strains. However, growth inhibition was not observed in the VP-16 group. The effect of irradiation on the tumor histology was severely expressed in the nucleus and cytoplasm on the 4th to 7th day. The high PCr/Pi ratio during 2 to 14 days after irradiation suggested reoxygenation in the tumors with a high hypoxic cell fraction. In the CDDP and VP-16 groups, without histological change, the changes of PCr and Pi were milder than that in the irradiation group. Thus the spectroscopic analysis is presumably expected to give us an earlier and more accurate information on the tumor than the conventional parameters.