Radiosensitivity test during low dose rate irradiation in normal and repair deficient cells

我们将正常和共济失调的毛细血管扩张细胞暴露在每天0.5Gy伽玛射线中。照射过程中细胞维持在GO状态。照射剂量为1~3Gy2次，分析融合早熟染色体凝聚技术的染色体畸变率。Giemsa染色显示，1Gy射线在正常细胞中诱导约0.36个片段，在AT细胞中约1.35个片段，表明AT细胞重接断裂的效果不如正常细胞。我们还用FISH技术分析了3Gy射线照射后的染色体交换。AT细胞有更多错接的断裂。用Calyculin-A诱导的PCC技术分析经3Gy射线照射的细胞传代后，两种细胞系的未连接断裂减少，错合断裂增加，表明AT细胞在累积一定数量的喙后开始重新连接断裂，G0 AT细胞观察到交换次数增加，这与高剂量率照射后的情况相似

We exposed normal and ataxia telangiectasia cells to 0.5 Gy per day to gamma ray. Cells were maintained under Go during irradiation. The dose was 1 to 3 Gy and chromosomal aberrations using fusion premature chromosomal condensation technique were analyzed. Giemsa staining showed that 1 Gy induces around 0.36 fragments in normal cells and around 1.35 in AT cells, indicating that AT cells rejoin breaks less effectively than normal cells. We also analyzed chromosomal exchange after exposure to 3 Gy using FISH techniques. AT cells have more misrejoined breaks. When cells irradiated with 3 Gy were subcultured and G2 chromosomal aberrations were analyzed using calyculin-A induced PCC technique, unrejoined breaks decreased and misrejoined breaks increased in both cell lines, suggesting that AT cells begin to rejoin breaks when a certain number of beaks are accumulated and an increased number of exchanges were observed in G0 AT cells, which is similar situation after high-dose-rate irradiation