制癌剤感受性試験としての腎被膜下移植法(subrenal capsule assay)における各種免疫抑制剤投与の効果

Abstract

各種免疫抑制剤を投与して腎被膜下移植腫瘍片への影響を比較し, 適切な免疫抑制剤の種類と投与方法について検討した.1)同系マウスモデルでは11日目までMBT-2腫瘍は順調に成長したが, 異系マウスモデルでは6日目で著明な細胞浸潤を認めた.2)同系マウスモデルの実験では, Azathioprine (AZT), mizoribine (MZR)投与群は11日目になると薬剤による腫瘍の成長抑制作用が出現するため, 6日目判定がより適切である.3)異系マウスモデルでも11日目判定では同様の成長抑制作用を認めた.6日目判定では腫瘍の成長は対照群≧CPM≧MZR>CPM+AZT>AZT投与群の順であった.4) 6日目判定における組織像では, CPM投与群は円形細胞浸潤を認めたが, MZR投与群は腫瘍細胞の構築はよく保たれていた.従って, 同系モデルに近い形でSRC assay法を行うには, MZR 200 mg/kg投与による6日目判定が最も有用である

We evaluated the effect of various immunosuppressive drugs in the SRC assay. We chose the most appropriate day to obtain the results of the SRC assay using the MBT-2 tumor. MBT-2 tumor-bearing mice of homogenic and heterogenic strains were separately given one of the three: cyclophosphamide, azathioprine or mizoribine. These drugs were evaluated on the 6th and the 11th day for the immunosuppressive effects expected from a host versus graft reaction. Concerning the homogenic mice that were injected with drugs, on the 11th day, the growth of the tumor was favorably suppressed in comparison with the growth of the control group (A-1) due to the anti-tumor effect of immunosuppressive drugs. We concluded that the 6th day was the most, appropriate day to obtain the results of this assay. Concerning the heterogenic mice, similar results were observed. In the mizoribine-group, we subcutaneously injected 200 mg/kg on alternate days. Yet the implanted tumor grew almost at the same rate as that of the A-1 group. In this group, a histological study showed reduction of the tumor cells and few inflammatory cells. We concluded that this drug was more useful than the others in the SRC assay and the suitable day for judgement was the 6th day.