Shu Hui, Dong Ya, Zhang Xue-Wen, Shen Xing, Xing Shuang, Yu Zu-Yin
School of Life Sciences, Anhui Medical University, Hefei 230032, Anhui Province, China.
Academy of Military Medical Sciences, Academy of Military Sciences, Beijing 100850, China.
Zhongguo Shi Yan Xue Ye Xue Za Zhi. 2025 Aug;33(4):1181-1189. doi: 10.19746/j.cnki.issn.1009-2137.2025.04.038.
To investigate the effect of irradiation dose rate of Co γ-ray on hematopoietic and immune cells in total body irradiation (TBI) mice.
After TBI with 8 Gy Co γ-ray at three irradiation dose rates of 0.027, 0.256 and 0.597 Gy/min, the survival and change of body weight of C57BL/6J mice were observed within 30 days. The peripheral blood parameters were examined at each time point within 30 days post-irradiation. The hematopoietic stem/progenitor cell counts of mice were examined on the 10 and 30 day post-irradiation by flow cytometry, as well as the proportions of immune cells in peripheral blood, bone marrow and spleen of mice on the 30 day post-irradiation.
After TBI with 8 Gy Co γ-ray, the 30-day survival rate of high dose-rate group was 0, which was significantly lower than 90% of medium dose-rate group and 100% of low dose-rate group (both < 0.001). The peripheral blood parameters of all three groups showed a sharp decline → low value → gradually recovering trend. The count of white blood cell, neutrophil, lymphocyte, red blood cell, platelet and hemoglobin level in the high dose-rate and medium dose-rate groups were significantly lower than those in the low dose-rate group on day 7-18 post-irradiation (all < 0.05), but there were no significant differences between the high dose-rate and medium dose-rate groups ( >0.05). On the 10 day after irradiation, the proportion and number of bone marrow hematopoietic stem/progenitor cells (including LK, LSK, LT-HSC, ST-HSC, and MPP cells) in the low dose-rate and medium dose-rate groups were significantly decreased compared to those in the normal group (all < 0.05), but there were no significant differences between the two groups ( >0.05). On the 30 day after irradiation, LSK, LT-HSC, ST-HSC and MPP cells in the low dose-rate group recovered to normal levels, while those in the medium dose-rate group were still significantly lower than those in the low dose-rate group (all < 0.001). The results of bone marrow and peripheral immune cell tests on the 30 day after irradiation showed that the ratios of T and B lymphocytes in the low dose-rate and medium dose-rate groups were reduced compared to that in the normal group (both < 0.05), while the ratio of neutrophils was increased ( < 0.01). The trend of changes in the spleen and peripheral blood was consistent.
The degree of hematopoietic and immune cell damage in mice after TBI with 8 Gy Co γ-ray is related to the dose rate, and low dose-rate irradiation can reduce the damage in the animal model. Therefore, choosing the appropriate dose rate of irradiation is a key factor in establishing an objective and reliable experimental animal model of irradiation.
探讨钴γ射线照射剂量率对全身照射（TBI）小鼠造血及免疫细胞的影响。
以0.027、0.256和0.597 Gy/min三种照射剂量率对C57BL/6J小鼠进行8 Gy钴γ射线全身照射后，观察30天内小鼠的存活情况及体重变化。照射后30天内各时间点检测外周血参数。照射后第10天和第30天通过流式细胞术检测小鼠造血干/祖细胞数量，以及照射后第30天小鼠外周血、骨髓和脾脏中免疫细胞的比例。
8 Gy钴γ射线全身照射后，高剂量率组30天生存率为0，显著低于中剂量率组的90%和低剂量率组的100%（均P<0.001）。三组外周血参数均呈急剧下降→低值→逐渐恢复的趋势。照射后第7 - 18天，高剂量率组和中剂量率组的白细胞、中性粒细胞、淋巴细胞、红细胞、血小板计数及血红蛋白水平均显著低于低剂量率组（均P<0.05），但高剂量率组与中剂量率组之间无显著差异（P>0.05）。照射后第10天，低剂量率组和中剂量率组骨髓造血干/祖细胞（包括LK、LSK、LT - HSC、ST - HSC和MPP细胞）的比例和数量与正常组相比均显著降低（均P<0.05），但两组之间无显著差异（P>0.05）。照射后第30天，低剂量率组的LSK、LT - HSC、ST - HSC和MPP细胞恢复至正常水平，而中剂量率组仍显著低于低剂量率组（均P<0.001）。照射后第30天骨髓和外周免疫细胞检测结果显示，低剂量率组和中剂量率组的T和B淋巴细胞比例较正常组降低（均P<0.05），而中性粒细胞比例升高（P<0.01）。脾脏和外周血的变化趋势一致。
8 Gy钴γ射线全身照射后小鼠造血及免疫细胞损伤程度与剂量率有关，低剂量率照射可减轻动物模型中的损伤。因此，选择合适的照射剂量率是建立客观可靠的照射实验动物模型的关键因素。
