Radiation and Environmental Science Centre, Focas Research Institute, Dublin Institute of Technology, Dublin.
Int J Radiat Biol. 2013 Mar;89(3):182-90. doi: 10.3109/09553002.2013.734942. Epub 2012 Oct 25.
The aim of this study was to compare levels of apoptosis, necrosis, mitotic cell death and senescence after treatment with both direct radiation and irradiated cell conditioned medium.
Human keratinocytes (HaCaT cell line) were irradiated (0.005, 0.05 and 0.5 Gy) using a cobalt 60 teletherapy unit. For bystander experiments, the medium was harvested from donor HaCaT cells 1 hour after irradiation and transferred to recipient HaCaT cells. Clonogenic assay, apoptosis, necrosis, mitotic cell death, senescence and cell cycle analysis were measured in both directly irradiated cells and bystander cells
A reduction in cell survival was observed for both directly irradiated cells and irradiated cell conditioned medium (ICCM)-treated cells. Early apoptosis and necrosis was observed predominantly after direct irradiation. An increase in the number of cells in G2/M phase was observed at 6 and 12 h which led to mitotic cell death after 72 h following direct irradiation and ICCM treatment. No senescence was observed in the HaCaT cell line following either direct irradiation or treatment with ICCM.
This study has shown that directly irradiated cells undergo apoptosis, necrosis and mitotic cell death whereas ICCM-treated cells predominantly undergo mitotic cell death.
本研究旨在比较直接辐射和辐照细胞条件培养基处理后细胞凋亡、坏死、有丝分裂细胞死亡和衰老的水平。
用人角质形成细胞（HaCaT 细胞系）用钴 60 远距离治疗机照射（0.005、0.05 和 0.5 Gy）。对于旁观者实验，在供体 HaCaT 细胞照射后 1 小时收获培养基并转移至受体 HaCaT 细胞。直接照射细胞和旁观者细胞均进行集落形成实验、细胞凋亡、坏死、有丝分裂细胞死亡、衰老和细胞周期分析。
直接照射细胞和辐照细胞条件培养基（ICCM）处理细胞的细胞存活率均降低。直接照射后主要观察到早期凋亡和坏死。直接照射后 6 和 12 小时观察到 G2/M 期细胞数量增加，导致 72 小时后有丝分裂细胞死亡，ICCM 处理后也观察到同样现象。HaCaT 细胞系在直接照射或 ICCM 处理后均未观察到衰老。
本研究表明，直接照射的细胞经历凋亡、坏死和有丝分裂细胞死亡，而 ICCM 处理的细胞主要经历有丝分裂细胞死亡。
