Haveman Jaap, Rodermond Hans, van Bree Chris, Wondergem Jan, Franken Nicolaas A P
Academic Medical Centre, University of Amsterdam Laboratory for Experimental Oncology and Radiobiology (LEXOR), Department of Radiotherapy, The Netherlands.
J Radiat Res. 2007 Mar;48(2):107-12. doi: 10.1269/jrr.0631. Epub 2007 Feb 14.
Irradiation of murine subcutaneous stroma before implantation of tumor cells leads to retarded tumor growth. This effect is called Tumor Bed Effect (TBE) and can be used to assess the sensitivity of stromal tissue to radiation. We tested the ability of stromal tissue to recover from X-ray-induced damage as a function of the time interval between X-irradiation and implantation of tumor cells over a period of 195 days. We also assessed the effects of a second test treatment of X-irradiation before implantation to assess residual damage by the first radiation treatment. The tumor bed effect in C57Bl10xDBA2 mice observed after X-ray treatment and implantation of M8013 cells (from a transplantable mouse mammary carcinoma) declines with the time that elapses between X-rays and implantation. Implantation of tumor cells 195 days after initial irradiation of 10 or 20 Gy resulted in a considerably smaller TBE. The half-time of the decay is estimated as about 50 days. The extent of the recovery was then tested in two-fraction experiments, with radiation fractions separated by intervals of 30 or 180 days. In the experiment with re-irradiation at an interval of 30 days after the first radiation dose of 20 Gy hardly any recovery was observed, whereas at an interval of 180 days a considerable recovery was observed. We presume that the recovery in TBE that was observed a long time after the irradiation results from a proliferative stimulus to endothelial cells which takes place during the post-irradiation period. The proliferative response leads to cell death of the X-ray damaged endothelial cells and thereafter these are replaced by healthy cells.
在植入肿瘤细胞之前对小鼠皮下基质进行照射会导致肿瘤生长迟缓。这种效应被称为肿瘤床效应（TBE），可用于评估基质组织对辐射的敏感性。我们测试了基质组织从X射线诱导的损伤中恢复的能力，该能力是作为X射线照射与肿瘤细胞植入之间的时间间隔的函数，时间跨度为195天。我们还评估了在植入前进行第二次X射线测试治疗的效果，以评估第一次放射治疗后的残留损伤。在用X射线治疗并植入M8013细胞（来自可移植的小鼠乳腺癌）后，在C57Bl10xDBA2小鼠中观察到的肿瘤床效应会随着X射线与植入之间时间的流逝而下降。在最初照射10或20 Gy后195天植入肿瘤细胞，会导致TBE明显变小。衰减的半衰期估计约为50天。然后在两部分实验中测试恢复程度，辐射部分间隔30或180天。在第一次给予20 Gy辐射剂量后间隔30天进行再照射的实验中，几乎未观察到任何恢复，而在间隔180天进行再照射时，则观察到了相当程度的恢复。我们推测，照射后很长时间观察到的TBE恢复是由于在照射后时期对内皮细胞的增殖刺激所致。增殖反应导致X射线损伤的内皮细胞死亡，随后这些细胞被健康细胞取代。
