Song Kyung-Hee, Kim Mi-Hyoung, Kang Seong-Mook, Jung Seung-Youn, Ahn Jiyeon, Woo Hee-Jong, Nam Seon Young, Hwang Sang-Gu, Ryu Sang-Young, Song Jie-Young
a Division of Radiation Cancer Research, Korea Institute of Radiological & Medical Sciences , Seoul , Republic of Korea.
b Laboratory of Immunology, College of Veterinary Medicine, Seoul National University , Seoul , Republic of Korea.
Int J Radiat Biol. 2015;91(10):795-803. doi: 10.3109/09553002.2015.1068461. Epub 2015 Jul 23.
In contrast to high-dose therapeutic irradiation, definitive research detailing the physiological effects of low-dose irradiation is limited. Notably, the immunological response elicited after low-dose irradiation remains controversial.
Female C57BL/6 mice were whole- body-irradiated with a single or three daily fractions up to a total dose of 0.1, 1, or 10 cGy. Blood and spleen were harvested 2, 7 and 14 days after irradiation.
The splenic CD4(+) T cell subpopulations were temporarily increased at 2 days after single or fractionated irradiation, whereas the percentage of dendritic cells (DC) and macrophages was decreased. Whereas CD8(+) T cell populations were decreased in single-dose irradiated mice at day 7, early and sustained reduction of CD8(+) T cell numbers was observed in fractionated- dose-irradiated mice from day 2 until day 14. In addition, single-dose irradiation resulted in a Th1 cytokine expression profile, whereas fractionated-dose irradiation drove a Th2 shift. Additionally, increased expression of immune-related factors was observed at early time-points with single-dose irradiation, in contrast to the dose-independent induction following fractionated-dose irradiation.
Our results demonstrate that low-dose irradiation modulates the immune response in mice, where the sensitivity and kinetics of the induced response vary according to the dosing method.
与高剂量治疗性照射不同，详细阐述低剂量照射生理效应的确定性研究有限。值得注意的是，低剂量照射后引发的免疫反应仍存在争议。
对雌性C57BL/6小鼠进行全身照射，单次或每日分三次照射，总剂量分别为0.1、1或10 cGy。在照射后2、7和14天采集血液和脾脏。
单次或分次照射后2天，脾脏CD4(+) T细胞亚群暂时增加，而树突状细胞（DC）和巨噬细胞的百分比降低。在单次照射的小鼠中，第7天CD8(+) T细胞群体减少，而在分次照射的小鼠中，从第2天到第14天观察到CD8(+) T细胞数量早期且持续减少。此外，单次照射导致Th1细胞因子表达谱，而分次照射则导致Th2偏移。另外，与分次照射后剂量依赖性诱导不同，单次照射在早期时间点观察到免疫相关因子表达增加。
我们的结果表明，低剂量照射可调节小鼠的免疫反应，其中诱导反应的敏感性和动力学根据给药方法而有所不同。
