【摘要】 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。更多还原

【Abstract】 Objective To investigated the 48-hour kinetic repair of G2-phase normal human liver cells (cell line L02) exposed to γ-rays. Methods The chromosomal breaks were detected by premature chromosome condensation technique. Results The chromatid-type and isochromatid-type breaks increased with increase of the dose at 0 hour measured by PCC, the number of chromatid-type breaks was several times more than that of isochromatid-type breaks.Through further 24-hour incubation after exposure to radiation,both of these types of breaks were repaired to different extents,i.e., by 50% for chromatid-type breaks,15% for isochromatid-type ones at most.At 48th hour,there was a slight change of chromosome breaks compared with that of 24th hour (P>0.05). Conclusion The main type of chromosomal break is chromatid-type after exposure to γ-rays,and these bveaks are easy to be repaired. Though the isochromatid-type break is obviously less than that of the chromatid-type but is difficult to be repaired, indicating that the isochromatid type break is the important factor causing cell death and canceration when cells bave been exposed to γ-radiation.;更多还原