不同射线诱发人外周血淋巴细胞微核的剂量-效应关系
An in vitro Study on Dose Effect Relationship of Micronuclei in Human Peripheral Lymphocytes Induced by Different Radiation Rays
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摘要:
目的 比较60Co γ 射线、X射线和137Cs γ 射线对人外周血淋巴细胞微核率的影响,并探讨其在低剂量受照者剂量估算中的应用意义。 方法 在0~1.00 Gy的剂量范围内,用60Co γ射线、X射线和137Cs γ射线(剂量率分别为0.440、0.073、0.810 Gy/min)照射离体人血,采用胞质分裂阻断微核法(cytokinesis-block micronucleus method,CB 微核法)培养和制片,计数分析双核CB 细胞中微核率和微核细胞率,拟合剂量-效应曲线,并计算不同射线的相对生物效能(relative biological effectiveness,RBE)。 结果 正常人群中微核自发率很低。采用0.05~1.00 Gy 的60Co γ 射线、X射线和137Cs γ 射线照射离体人血后,诱发的淋巴细胞微核率和微核细胞率均随照射剂量增加,二者呈正相关(P<0.01)。采用二次多项式拟合的微核剂量-效应曲线回归方程分别为& #374;1 =4.847 3 + 59.342 2 D + 37.364 9 D2(60Co γ 射线)、& #374;2 = 1.620 9 + 55.130 8 D +12.650 4 D2(X射线)和& #374;3 = 5.085 9 + 7.526 9 D + 37.233 0 D2(137Cs γ 射线),曲线的拟合指数(R2)分别为0.982 7、0.994 8 和0.998 6,回归系数有统计学意义(P<0.001)。不同类型、不同能量的辐射诱发CB微核的RBE不是单一值,尤其在低剂量辐射照射时RBE值较大。 结论 辐射诱发的淋巴细胞微核与辐射剂量有良好的回归关系,建立的剂量-效应曲线可为低剂量照射的医疗救治和预后评估提供生物剂量估算依据,但需充分考虑辐射类型和辐射能量。 Abstract:Objective Comparing the differential influence of radiation rays on the micronucleus induction rate in peripheral lymphocyte and estimating the occupational exposure dose. Methods The in vitro healthy human blood was irradiated at 0-1.00 Gy level with 60Co γ rays, X rays and 137Cs γ rays respectively(dose rates were 0.440, 0.073 and 0.810 Gy/min respectively). After the blood cells were cultured and harvested, the lymphocytes micronuclei were counted through CB micronuclei method, lymphocyte micronuclei dose-effect curve was constructed, and relative biological effective(RBE)values of micronucleus were derived. Results The spontaneous rate of human lymphocyte micronucleus was very low, but after irradiation with 0.05-1.00 Gy, micronucleus frequency and micronucleus cells frequency increased in a manner correlated to the dose(P<0.01).The regression equations of dose-effect curve of micronuclear were& #374;1 = 4.847 3 + 59.342 2 D + 37.364 9 D2(60Co γ rays), & #374;2 = 1.620 9 + 55.130 8 D + 12.650 4 D2(X rays)and & #374;3 = 5.085 9 + 7.526 9 D + 37.233 0 D2(137Cs γ rays)respectively. By F test, the regression coefficient of the rate of micronuclei cells and the dose were statistically significantly(P<0.001). The curve fitting exponents were 0.982 7, 0.994 8 and 0.998 6 respectively. Statistical analysis showed that relative biological effective(RBE)values of micronucleus rate, which induced by different kinds of radiation and different energy radiation, were not the same value. Conclusion A regression equation of doseeffect curve of peripheral lymphocyte micronucleus induced by irradiation was constructed in this laboratory and showed good degree of fitness. It could provide evidence for setting medical remedy plan and evaluating prognosis of the patient with low dose exposure. The kind and energy of radiation should be considered in combined manner.
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