文章基本信息

标题：Characteristics of human CD34 cells exposed to ionizing radiation under cytokine-free conditions
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作者：Junya Ishikawa ; Naoki Hayashi ; Masaru Yamaguchi 等
期刊名称：Journal of Radiation Research
印刷版ISSN：0449-3060
电子版ISSN：1349-9157
出版年度：2015
卷号：56
期号：4
页码：678-690
DOI：10.1093/jrr/rrv024
摘要：To clarify the mechanisms underlying radiation-induced hematopoietic stem cell death, we investigated the effects of excessive ionizing radiation on the clonogenic potential of CD34( ) cells obtained from human umbilical cord blood under cytokine-free conditions. The CD34( ) cells were X-ray-irradiated (up to 2 Gy) and were cultured for 0-48 h under cytokine-free conditions. At various time-points, the CD34( ) cells were investigated for survival, clonogenic potential and the generation of mitochondrial superoxide. At 12 h after X-ray irradiation, the number of viable cells had decreased to ∼70-80% compared with the 0-h non-irradiated control, whereas the clonogenic potential in the X-ray-irradiated cells had decreased to ∼50%-60% compared with the 0-h non-irradiated control. Furthermore, significant generation of mitochondrial superoxide was observed at 6 h, and reached a maximum value between 12 and 24 h after X-ray irradiation. However, no significant differences were observed between non-irradiated and X-ray-irradiated cells in terms of the generation of reactive oxygen species or in the intracellular mitochondrial contents. In addition, a cDNA microarray analysis showed that the majority of the altered genes in the CD34( ) cells at 6 h after X-ray irradiation were apoptosis-related genes. These results suggest the possibility that the elimination of the clonogenic potentials of CD34( ) cells involves the generation of mitochondrial superoxide induced by ionizing radiation. © The Author 2015. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.
关键词：CD34 cells;clonogenic potential;radiation;superoxide