Watanabe M, Suzuki M, Suzuki K, Nakano K, Watanabe K
Division of Radiation Biology, Faculty of Pharmaceutical Sciences, Nagasaki University, Japan.
Int J Radiat Biol. 1992 Dec;62(6):711-8. doi: 10.1080/09553009214552661.
We have measured expression of transformed phenotypes in human embryo (HE) cells repeatedly irradiated with a dose of 7.5 cGy per week throughout the life span of these cells in vitro. Irradiation was repeated until the cells had accumulated 195 cGy at which time the cells had reached the equivalent of their 26th passage and samples of cells at several passages were assayed for cell survival by colony formation, for mutation at hypoxanthine guanine phosphoribosyl transferase (HGPRT) locus and for transformation by focus formation. The lifespan (mean population doublings) of multiple irradiated cultures with a total dose of 97.5 cGy was slightly, but significantly, prolonged over that of controls. For example, if cells had accumulated 195 cGy, the maximum number of cell division of HE cells in vitro extended to 130-160% of non-irradiated control. Although transformed foci were not observed with cells until cells had accumulated 97.5 cGy, it increased with increasing accumulated dose. No cells, however, showed unlimited life span in vitro and also expressed tumorigenicity.
我们在体外对人胚（HE）细胞进行了测量，这些细胞在其整个生命周期内每周接受7.5 cGy的剂量重复照射。照射一直重复，直到细胞累积剂量达到195 cGy，此时细胞已达到相当于第26代，对几个传代阶段的细胞样本进行了集落形成法检测细胞存活率、次黄嘌呤鸟嘌呤磷酸核糖转移酶（HGPRT）位点突变以及焦点形成法检测细胞转化。总剂量为97.5 cGy的多次照射培养物的寿命（平均群体倍增数）比对照略有延长，但具有显著差异。例如，如果细胞累积剂量达到195 cGy，体外HE细胞的最大细胞分裂数扩展至未照射对照的130% - 160%。虽然直到细胞累积剂量达到97.5 cGy才观察到转化灶，但随着累积剂量的增加而增多。然而，没有细胞在体外表现出无限寿命，也未表现出致瘤性。
