材料期刊网

以0,0.05,0.1,0.25,0.5 Gy~(12)C~(6+)离子全身预辐照昆明小鼠,间隔4 h后再对小鼠进行4Gy全身辐射.辐照后12 h用流式细胞仪检测小鼠胸腺脾脏细胞在各细胞周期时相的百分率,同时用单细胞电泳检测受辐射小鼠胸腺脾脏细胞DNA损伤程度.结果显示,相对于大剂量预照射组,各低剂量预照射组胸腺细胞S期细胞百分率显著减少;脾脏细胞G_0/G_1期细胞百分率明显减少;同时胸腺脾脏细胞的拖尾率及拖尾长度明显减少,以0.1 Gy预辐照效果最为明显.这些结果表明,低剂量预辐射处理可以减弱胸腺细胞的S期阻滞及脾脏细胞的G_1期阻滞,并明显减轻胸腺脾脏细胞的DNA损伤程度.

To investigate the effect of low dose ~(12)C~(6+) pre-irradiation on the cell cycle progression and DNA damage in mouse thymus and spleen, Kun-Ming strain mice were whole-body irradiated with 0, 0.05, 0.1, 0.25 or 0.5 Gy of ~(12)C~(6+) ions as the pre-exposure dose, and were then irradiated with 4 Gy of ~(12)C~(6+) ions as a challenging dose at 4 h after per-exposure. At 12 h after irradiation, cell cycles of thymus and spleen were analyzed by FACS, and the frequencies of cells with tail moment and the tail lengths were determined by the single cell gel electrophoresis. The results showed that compared with high-dose exposure group, the percentages of S phase cells on thymus and the percentages of G_0/G_1 phase cells on spleen significantly decreased via pre-exposure to low-dose ~(12)C~(6+) ions. Moreover, the low-dose pre-exposure significantly reduced length of the tails and the number of cells with tail, especially at the 0.1 Gy pre-exposure. The data suggested that pre-exposure to low-dose heavy ion can alleviate S phase arrest in thymus cells and the G_1 phase arrest in spleen cell, and the degree of DNA damage.