Differential effects of x-irradiation on immature and mature hippocampal neurons in vitro
Differential effects of x-irradiation on immature and mature hippocampal neurons in vitro
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DOI：
10.1016/j.neulet.2006.01.048
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发表时间：
2006-05-15
影响因子：
2.5
通讯作者：
Shirao, Tomoaki
中科院分区：
文献类型：
--
作者：
Shirai, Katsuyuki;Mizui, Toshiyuki;Shirao, Tomoaki
对神经元祖细胞的X射线照射会导致大脑功能障碍，例如成年后的智力迟钝。然而，很少有人知道的神经元的辐射敏感性的程度，在发育阶段，他们是最脆弱的。在这项研究中，我们比较了辐射对成熟神经元和未成熟神经元的影响。从胚胎第18天的胎鼠海马制备原代分离的神经元培养物。在体外培养7或21天（DIV）时对培养的细胞进行X射线照射，并在照射后12或24小时固定细胞。然后用4 '，6-二脒基-2-苯基吲哚（DAPI）或末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（TUNEL）对细胞进行染色。细胞核固缩和DNA断裂是细胞凋亡的特征性形态学改变，可定量测定细胞凋亡的变化。光学显微镜与微分干涉对比显示，30戈伊的辐射增加7-DIV神经元，但不是在21 -DIV神经元的细胞收缩。DAPI成像定量分析显示，30戈伊照射24 h后7-DIV神经元的固缩变化显著增强。与此相反，这种辐射没有增强任何固缩的变化，在21 -DIV神经元后24小时。进一步的TUNEL染色也显示照射24 h后21-DIV神经元细胞核中没有任何DNA断裂。因此，我们发现，21 -DIV有丝分裂后神经元的辐射敏感性显着低于7-DIV神经元，表明这种神经元的敏感性取决于其发育阶段。(c)2006爱思唯尔爱尔兰有限公司保留所有权利。
X-irradiation to neuronal progenitor cells causes brain dysfunctions, such as a mental retardation, in adulthood. However, little has been known about the degree of radiosensitivity of neurons in the developmental stages at which they are most vulnerable. In this study we compared the effect of irradiation on mature neurons with that on immature neurons. Primary dissociated neuronal cultures were prepared from fetal rat hippocampi of embryonic day 18. X-irradiations were performed on the cultured cells at 7 or 21 days in vitro (DIV), and the cells were fixed at 12 or 24 h after irradiation. Then the cells were stained with 4',6-diamidino-2-phenylindole (DAPI) or terminal deoxynucleotidyl transferase- mediated dUTP nick end labeling (TUNEL). The apoptotic changes were measured quantitatively by nuclear pyknosis and DNA fragmentation-both characteristic morphological changes of apoptosis. Light microscopy with differential interference contrast showed that 30 Gy of irradiation increased cellular shrinkage in 7-DIV neurons but not in 21 -DIV neurons. Quantitative analysis using DAPI imaging showed that 30 Gy of irradiation significantly enhanced pyknotic changes in 7-DIV neurons after 24 h. In contrast, this irradiation did not enhance any pyknotic changes in 21 -DIV neurons after 24 h. Further TUNEL staining also showed that the irradiation did not enhance any DNA fragmentation in nuclei of 21-DIV neurons after 24 h. Hence, we showed that the radiosensitivity of 21 -DIV postmitotic neurons was significantly lower than that of 7-DIV neurons, indicating that the susceptibility of such neurons depends on their developmental stage. (c) 2006 Elsevier Ireland Ltd. All rights reserved.