Joksic Gordana, Petrović Sandra
Vinca Institute of Nuclear Sciences, Belgrade, Serbia and Montenegro.
J Environ Pathol Toxicol Oncol. 2004;23(3):195-206. doi: 10.1615/jenvpathtoxoncol.v23.i3.30.
The aim of this study was to evaluate whether or not low radiation doses can induce an adaptive response in human lymphocytes exposed in vivo. We examined chromosome aberrations, micronuclei, radiosensitivity, and apoptosis in the peripheral blood of young radiation workers (mean age 35.8 +/- 9) with 14.9 +/- 5.2 years of occupational exposure to ionizing radiation. Adaptive response was estimated using two parameters of radiosensitivity: micronuclei and apoptosis. Baseline and radiation-induced micronuclei (2 Gy, 60Co gamma-rays) were assessed with the cytochalasin block micronucleus (CBMN) test. Cytotoxicity was analyzed by flow cytometry for human white blood cells identifying cells that displayed apoptosis-associated DNA condensation. In the exposed group, eight out of 34 cases were dicentric-positive. A statistically significant difference (t = 3.1, p less 0.01) was found between the dicentric-positive and dicentric-negative group in the yield of baseline micronuclei. However, the yield of radiation-induced micronuclei between these groups did not differ significantly (t = -1.57, p less 0.15). An inverse correlation between baseline micronuclei and apoptosis group was noted in the dicentric-positive group (r = -0.53, p less 0.45). Our study showed that occupational exposure to low doses of ionizing radiation failed to induce adaptation of blood lymphocytes to the challenge dose. An inverse relationship between baseline micronuclei and apoptosis in the dicentric-positive group indicates that chronic exposure to low doses of ionizing radiation depresses the ability of leukocytes to undergo apoptosis. Our study also showed that the effects of radiation-induced cytotoxicity in occupationally exposed persons could be determined by flow cytometry.
本研究的目的是评估低辐射剂量是否能在体内暴露的人类淋巴细胞中诱导适应性反应。我们检测了年轻辐射工作者（平均年龄35.8±9岁，职业性接触电离辐射14.9±5.2年）外周血中的染色体畸变、微核、放射敏感性和细胞凋亡情况。使用放射敏感性的两个参数（微核和细胞凋亡）来评估适应性反应。通过细胞松弛素阻断微核（CBMN）试验评估基线微核和辐射诱导的微核（2 Gy，60Coγ射线）。通过流式细胞术分析人白细胞的细胞毒性，以识别显示凋亡相关DNA浓缩的细胞。在暴露组中，34例中有8例双着丝粒阳性。双着丝粒阳性组和双着丝粒阴性组在基线微核产量上存在统计学显著差异（t = 3.1，p < 0.01）。然而，这些组之间辐射诱导的微核产量没有显著差异（t = -1.57，p < 0.15）。在双着丝粒阳性组中，基线微核与细胞凋亡组之间存在负相关（r = -0.53，p < 0.45）。我们的研究表明，职业性接触低剂量电离辐射未能诱导血液淋巴细胞对激发剂量产生适应性。双着丝粒阳性组中基线微核与细胞凋亡之间的负相关表明，长期接触低剂量电离辐射会抑制白细胞发生细胞凋亡的能力。我们的研究还表明，流式细胞术可确定职业暴露人群中辐射诱导的细胞毒性作用。
