低剂量γ射线照射诱导小鼠骨髓细胞染色体畸变的适应性反应

A study on adaptive response of chromosome aberrations in bone marrow cells induced by low dose radiation in mice

目的 探讨低剂量照射后不同攻击剂量对小鼠骨髓细胞染色体畸变的适应性反应。方法 小鼠预先用13 7 Csγ射线 0 0 5Gy(D1,预照射剂量 )低剂量全身照射 (低剂量照射组 )、剂量率 0 0 5 4Gy/min ,3h后再接受 0 7Gy或 1 0Gy(D2 ,攻击剂量 )全身照射、剂量率 0 87Gy/min ,同时设单纯较大剂量组为对照组 ,观察骨髓细胞染色体畸变率。结果 0 0 5Gy低剂量全身照射后 3h再接受 0 7Gy或 1 0Gy全身照射组 ,小鼠骨髓细胞染色体畸变率和单体断裂 (ctb)均明显低于其相应对照组 ,而与对照组相比 ,低剂量照射组断片 (ace)减少不明确。结论 预先的低剂量辐射能够诱导小鼠骨髓细胞染色体畸变的适应性反应 ,从而使随后较大剂量辐射所致的染色体损伤减轻。

Objective To investigate adaptive response of chromosome aberrations in bone marrow cells induced by low dose γ-radiation i n mice. Methods C57BL/6 mice were subjected to whole body irrad iation with 0.05 Gy (D 1,0.054 Gy/min as preliminary exposure) γ-ray 3h bef ore exposed to whole body irradiation with 0.7 Gy or 1.0 Gy (D 2,0.87 Gy/mi n as attacking exposure). The controls were exposed to whole body irradiation wi th 0.7 Gy or 1.0 Gy only. Then the frequencies of chromosome aberrations in bo ne marrow cells were observed. Results The frequencies of chrom osome aberrations and chromatid break(ctb) in bone marrow cells in mice irradiat ion with D 1 and D 2 exposure were all significantly lower than that of irradi ation with D 2 only. There was not significant decrease in the rat e of acentric fragment(ace) irradiation with D 1 and D 2 exposure compare d with th at of the controls. Conclusion Low dose γ-radiat ion could induce adaptive response of chromosome aberrations in bone marrow cell s in mice, which could lessen the chromosome damages caused by subsequent large dose radiation exposure.