Keulers R A, de Roon A R, de Roode S, Tates A D
MGC-Department of Radiation Genetics and Chemical Mutagenesis, Leiden University Medical Centre, The Netherlands.
Photochem Photobiol. 1998 Apr;67(4):426-32.
The DNA-damaging potential of ultraviolet-B (UVB) radiation was investigated by analyzing the frequency and origin of micronuclei (MN) in cytokinesis-blocked, binucleated (BN) peripheral blood lymphocytes (PBL) and cloning efficiencies (CE) of PBL after exposure to different fluences of UVB. In total, PBL obtained from five normal donors were investigated. The PBL from all donors showed a dose-related, linear-quadratic increase in the frequency of MN per 1000 BN cells and in the frequency of micronucleated BN cells. In two experiments the origin of UVB-induced MN was studied by analyzing MN for the presence or absence of centromeres by applying the MN assay in combination with a centromeric probe and fluorescence in situ hybridization. This revealed, for the first time, that UVB-induced MN were centromere negative, indicating that UVB acted exclusively as a clastogenic agent in the tested dose range. The PBL from all donors showed a clear dose-dependent decrease in CE, after UVB exposure. The UVB-exposed PBL from all donors showed an inverse relationship between the induction of MN and the decrease in CE, but regression analysis revealed no correlation between the induction of MN and the decrease in cell survival. It is concluded that UVB has a clastogenic and cytotoxic effect on PBL.
通过分析细胞分裂阻滞的双核（BN）外周血淋巴细胞（PBL）中微核（MN）的频率和来源以及暴露于不同剂量的紫外线B（UVB）后PBL的克隆效率（CE），研究了UVB辐射的DNA损伤潜力。总共研究了从五名正常供体获得的PBL。所有供体的PBL每1000个BN细胞中的MN频率和微核化BN细胞的频率均呈剂量相关的线性二次增加。在两项实验中，通过将MN检测与着丝粒探针和荧光原位杂交相结合，分析MN中着丝粒的有无，研究了UVB诱导的MN的来源。这首次表明，UVB诱导的MN着丝粒阴性，表明在测试剂量范围内UVB仅作为一种断裂剂起作用。所有供体的PBL在UVB暴露后CE均呈现明显的剂量依赖性下降。所有供体暴露于UVB的PBL在MN诱导和CE下降之间呈现反比关系，但回归分析显示MN诱导与细胞存活下降之间无相关性。得出的结论是，UVB对PBL具有断裂和细胞毒性作用。
