Several studies have demonstrated that mitochondria are critically involved in the pleiotropic manifestation of radiation effects. While conventional whole-cell irradiation compromises the function of mitochondria, the effects of subcellular targeted radiation are not yet fully understood. In this study, normal human diploid cells with cell-cycle indicators were irradiated using a synchrotron X-ray microbeam, and mitochondrial membrane potential was quantified by JC-1 over the 72-h period postirradiation. Cytoplasmic irradiation was observed to temporarily enlarge the mitochondrial area with high membrane potential, while the total mitochondrial area did not change significantly. Unexpectedly, cell-nucleus irradiation promoted a similar increase not only in the mitochondrial areas with high membrane potential, but also in those with low membrane potential, which gave rise to the apparent increase in the total mitochondrial area. Augmentation of the mitochondrial area with low membrane potential was predominantly observed among G₁ cells, suggesting that nucleus irradiation during the G₁ phase regulated the mitochondrial dynamics of the cytoplasm, presumably through DNA damage in the nucleus.

几项研究表明，线粒体在辐射作用的多效性表现中起关键作用。尽管常规的全细胞辐射损害了线粒体的功能，但亚细胞靶向辐射的作用尚未完全了解。在这项研究中，使用同步加速器X射线微束辐照具有细胞周期指示剂的正常人二倍体细胞，并在辐照后72小时内通过JC-1量化线粒体膜电位。观察到细胞质辐射可暂时扩大具有高膜电位的线粒体面积，而总线粒体面积没有明显变化。出乎意料的是，细胞核辐射不仅在膜电位高的线粒体区域促进了类似的增加，但在膜电位低的人群中，线粒体总面积也明显增加。在G中主要观察到膜电位低的线粒体区域增大。_1个细胞，提示G ₁期的核辐射可能通过核中的DNA损伤来调节细胞质的线粒体动力学。