中文摘要：

目的探讨在α粒子、γ射线以及联合照射下淋巴母细胞微核率的剂量效应。方法以HMy2．CIR淋巴母细胞为对象，分别以不同剂量的α粒子和γ射线进行照射，以及先以0．025～0．500Gy的理粒子照射后即刻以不同剂量的γ射线进行照射，用胞质分裂阻断法检测淋巴细胞微核，建立不同照射条件下淋巴母细胞微核率的剂量-效应曲线。结果对于γ射线照射，微核率剂量-效应符合线性平方模型Y=c＋ctD＋βD2对于Ot粒子照射，当照射剂量〈0．250Gy时，细胞微核率随剂量的增加呈线性增加，当其剂量进一步增加时，微核率剂量-效应曲线呈现下弓型。可以采用反映辐射旁效应的BaD模型Y=c＋αD＋σ[1-exp（-8D）]exp（-130）进行很好地拟合。对于联合照射，当d粒子剂量较低时，微核率的剂量效应与γ射线照射时的相似；但当d粒子剂量较大时，微核率的剂量一效应更接近于α粒子照射。同时，0．2、0．5Gyd粒子联合γ射线照射引起的微核率显著高于它们单独照射时的微核率之和（t=5．22—11．86，P〈0．05）。结论α粒子照射具有与γ射线不同的辐射损伤规律，辐射旁效应可能在其中发挥了重要作用，而联合照射则可以引起细胞损伤的协同增强。

英文摘要：

Objective To investigate the dose-response of micronuclei （MN） frequency in the lymphocytes irradiated with or without combination of α-particles and γ-rays. Methods Human lymphoblast cells HMy2. CIR were irradiated with 0 - 1 Gy of α-particles, 0 - 5 Gy of γ-rays, and 0. 025 - 0. 5 Gy of a-particles followed by different doses of γ-rays, respectively. The micronuclei （MN） in the irradiated cells were measured with the cytokinesis block technique, and the dose-responses of MN were established under different irradiation conditions. Results For γ-ray irradiation, the dose-response of MN was well-fit by the linear-quadratic model with an equation Y = c ＋ αD ＋ βD2. For α-particle irradiation, the MN induction increased linearly with the dose less than 0. 250 Gy. But when the dose of α-particles increased continually, the dose-response curve bended and could be well fit with the BaD model Y = c ＋ aD ＋ cr[ 1 - exp（ - 8D） ] exp（ - 13D） where radiation-induced bystander effect （RIBE） was indicated. For the combined exposure, the dose-response of MN was similar to that of γ-irradiation when the dose of α- particles was lower than 0. 1 Gy, but it was similar to that of α-irradiation when the dose of α-particles was higher. When the dose of α-particles was 0.2 and O. 5 Gy, MN induced by the mixed radiation were significantly higher than the sum of corresponding irradiation alone （ t = 5.22 - 11.86, P 〈 0.05 ）. Conclusions The radiation damage of α-particles differs from that of γ-rays, where RIBE may be involved. The combination irradiation of α-particles and γ-rays has a synergistic effect on radiation damage of lymphoblast cells.