Pincheira J, López I, Sanhueza S, Ferruz P, Navarrete M H, Santos M J, López-Sáez J F
Human Genetics Program, ICBM, Faculty of Medicine, Universidad de Chile.
Biol Res. 1999;32(4):297-306. doi: 10.4067/s0716-97601999000400009.
The effect of the G2 repair of chromosomal damage in lymphocytes from workers exposed to low levels of X- or gamma-rays was evaluated. Samples of peripheral blood were collected from 15 radiation workers, 20 subjects working in radiodiagnostics, and 30 healthy control donors. Chromosomal aberrations (CA) were evaluated by scoring the presence of chromatid and isochromatid breaks, dicentric and ring chromosomes in lymphocytes with/without 5 mM caffeine plus 3 mM-aminobenzamide (3-AB) treatment during G2. Our results showed that the mean value of basal aberrations in lymphocytes from exposed workers was higher than in control cells (p < 0.001). The chromosomal damage in G2, detected with caffeine plus 3-AB treatment was higher than the basal damage (untreated conditions), both in control and exposed populations (p < 0.05). In the exposed workers group, the mean value of chromosomal abnormalities in G2 was higher than in the control (p < 0.0001). No correlation was found between the frequency of chromosome type of aberrations (basal or in G2), and the absorbed dose. Nevertheless, significant correlation coefficients (p < 0.05) between absorbed dose and basal aberrations yield (r = 0.430) or in G2 (r = 0.448) were detected when chromatid breaks were included in the total aberrations yield. Under this latter condition no significant effect of age, years of employment or smoking habit on the chromosomal aberrations yield was detected. However, analysis of the relationship between basal aberrations yield and the efficiency of G2 repair mechanisms, defined as the percentage of chromosomal lesions repaired in G2, showed a significant correlation coefficient (r = -0.802; p < 0.001). These results suggest that in addition to the absorbed dose, the individual G2 repair efficiency may be another important factor affecting the chromosomal aberrations yield detected in workers exposed to low-level ionizing radiation.
评估了低水平X射线或γ射线照射工人淋巴细胞中染色体损伤的G2修复效应。采集了15名放射工作人员、20名从事放射诊断工作的受试者以及30名健康对照者的外周血样本。通过对淋巴细胞中染色单体和等染色单体断裂、双着丝粒和环状染色体的存在情况进行评分来评估染色体畸变（CA），这些淋巴细胞在G2期接受/未接受5 mM咖啡因加3 mM 3 -氨基苯甲酰胺（3 - AB）处理。我们的结果显示，受照射工人淋巴细胞的基础畸变平均值高于对照细胞（p < 0.001）。在对照人群和受照射人群中，用咖啡因加3 - AB处理检测到的G2期染色体损伤均高于基础损伤（未处理情况）（p < 0.05）。在受照射工人组中，G2期染色体异常的平均值高于对照组（p < 0.0001）。未发现染色体畸变类型的频率（基础或G2期）与吸收剂量之间存在相关性。然而，当将染色单体断裂纳入总畸变产额时，检测到吸收剂量与基础畸变产额（r = 0.430）或G2期（r = 0.448）之间存在显著相关系数（p < 0.05）。在这种情况下，未检测到年龄、工作年限或吸烟习惯对染色体畸变产额有显著影响。然而，对基础畸变产额与G2修复机制效率（定义为G2期修复的染色体损伤百分比）之间关系的分析显示，存在显著相关系数（r = -0.802；p < 0.001）。这些结果表明，除吸收剂量外，个体G2修复效率可能是影响低水平电离辐射照射工人中检测到的染色体畸变产额的另一个重要因素。
