Effect of Low Dose Irradiation on the Induction of Sister-Chromatid Exchange in V-79 Cells

低劑量加馬射線誘發中國灰鼠纖維母細胞姐妹染色體交換之效應

林松水(Song-Shei Lin) ； 田雨生(Yeu-Sheng Tyan) ； 楊素珍(Su-Jing Yang)

《放射治療與腫瘤學》 8卷1期 (2001/03) Pp. 25-32

https://doi.org/10.6316/TRO/200108(1)25

摘要

目的：以低劑量的銫-137加馬射線照射中國灰鼠纖維母細胞（V-79），並就其姐妹染色分體交換（SCE）、姐妹染色分體交換之百分比分佈情形、有絲分裂指數、複製係數等項目加以分析。
材料與方法：中國灰鼠纖維母細胞以低劑量的銫-137加馬射線照射，劑量率為每分鐘0.1 Gy，實驗組的照射劑量分別為0.01，0.05，0.1，0.25及0.5 Gy五組。以姐妹染色分體對比染色法連續計數一百個第二分裂中期細胞的姐妹染色分體交換比率，進一步以紐門基測試法（Newman-Keuls test）作組間的交互配對比較。另外亦分析照射後有絲分裂指數和複製係數的改變情形。
結果：實驗數據顯示，從控制組與0.01、0.05 Gy兩組比較，其姐妹染色分體交換比率分別增加至36%和40%。劑量升高到0.25、0.5 Gy兩組則較控制組增加到50%和53%的百分比，顯示加馬射線誘增姐妹染色分體交換比率隨劑量增加有趨於飽和之現象。更進一步將每個細胞產生姐妹染色分體交換數區分為四組區域：區域I（≦5）、區域II（6-8）、區域III（9-11）以及區域IV（≧12）。結果顯示照射組劑量處理的細胞姐妹染色分體交換百分比主要分佈於區域II和區域III，且這二區域合起來的百分比為66-71%左右，然而控制組的姐妹染色分體交換百分比主要是分佈於區域I。
結論：本實驗結果明白指出低劑量飽-137加馬射線，能誘增中國灰鼠纖維母細胞的姐妹染色分體交換，且劑量越高則越趨於飽和狀態。低劑量加馬射線的照射不僅提高了姐妹染色分體交換率，同時也改變了其分佈的區間，照射後主要集中於交換數高之區段。

關鍵字

中國灰鼠纖維母細胞 ； 姐妹染色分體交換 ； 放射線照射

並列摘要

Purpose: Chromosomal changes, chromosome aberrations and sister-chromatid exchanges are widely used as indicators of chromosomal DNA damage. The relationship between numbers of SCE and low dose irradiation in V-79 cells was investigated.
Materials and Methods: The Chinese hamaster cells, V-79 cell line, were grown and irradiated by low doses of 137Cs γ-ray at an exposure dose rate of 0.1 Gy/min. The sister-chromatid exchanges were stained by Sorensen's buffer containing Hoechst and Giemsa. Newman-Keuls test was employed to analyze the difference of SCEs between one group and others. The replication index and mitotic index of cells after the treatment of low dose γ-ray were also analyzed.
Results: The frequency of sister-chromatid exchange in the 0.01 Gy and 0.05 Gy groups comparing to control group were 36% and 40%, respectively. While the ratios of SCE in higher treated dose for 0.25 and 0.5 Gy were 50% and 53%, respectively. With dose increasing, ratios of SCE became saturated. In addition, the data were analyzed by dividing into four sections (≦5, 6-8, 9-11, and≧12) based on SCE numbers in each cell. The results demonstrated that SCE numbers in all treated groups were mainly in 6~8 and 9~11 sections, and percentages were about 66~68 %. It was only 46% for control group and 52% fall down in the section of≦5. The section of ≧12 in control group has only 2%.
Conclusions: Low dose irradiation of 137Cs indeed induced SCE in V79 cells as low as 0.01 Gy, but not increase linearly. In this study, SCE numbers increased quickly at first division from 0 to 0.01 Gy, and the increased frequency in second part was slow down. Low dose irradiation not only increase SCE numbers, but also change the distribution of SCE numbers.

並列關鍵字

V-79 cells ； Sister-chromatid exchange ； Irradiation