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目的研究人类正常肝细胞经γ射线诱导染色体损伤的动态修复。方法应用早熟染色体凝集技术对人类正常肝脏细胞经γ射线照射导致的染色体损伤后48h内的动态修复过程进行研究。结果照射后原初染色单体断裂和等点染色单体断裂数随着照射剂量的增加而增多,染色单体断裂显著多于等点染色单体断裂;经过24h的继续培养,这两种类型的损伤都有不同程度的修复,约50%染色单体断裂得到修复,而等点染色单体断裂的修复率最多为15%;经过48h的照射后培养,染色体损伤的水平与24h相比没有显著差异。结论肝细胞经γ射线照射后染色体损伤的主要形式是染色单体断裂,易于修复;虽然等点染色单体断裂数量较少,但修复困难。提示等点染色体断裂是细胞经γ射线照射后死亡和癌变的一个重要因素。
Objective To study the dynamic repair of chromosome damage induced by γ-rays in human normal liver cells. Methods The precocious chromosome agglutination technique was used to study the dynamic repair process of human normal liver cells within 48 hours after chromosomal damage caused by γ-ray irradiation. Results The numbers of rupture of primary chromatid and the number of rupture of isodose dyed monomer increased with the increase of irradiation dose, and the number of chromatid cleavage was significantly more than that of chromatid dying at irradiation. After 24 hours of continuous culture, The injury was repaired in varying degrees, and about 50% of the chromatid breaks were repaired, while the repair rate of the isochromatic chondriosomes was up to 15%. After 48 hours of irradiation, the level of chromosome damage was not significant compared with that of 24h difference. Conclusions The main form of chromosome damage after irradiated by γ-rays in hepatocytes is the chromatid fragmentation, which is easy to repair. Although the number of iso-chromatid fragmentation is small, the repair is difficult. Tip chromosome cleavage is the cell by γ-ray irradiation after death and cancer is an important factor.