晚期混合裂变产物内照射诱发大鼠外周血淋巴细胞HPRT基因位点突变与微核的比较研究

Mutations at HPRT loci and micronuclei induced by late fission products in peripheral blood lymphocytes of rats\

目的 探索ＨＰＲＴ 基因位点突变检测作为辐射生物剂量计的可行性。方法 运用多核细胞法及胞质分裂阻断微核（ＣＢＭＮ） 法研究大鼠外周血淋巴细胞的ＨＰＲＴ基因位点突变及微核与累积剂量、剂量率之间关系。结果 静注晚期混合裂变产物后第１ 天（ 累积剂量１－７３ ｃＳｖ） ，与对照组相比，ＨＰＲＴ 位点变异频率（Ｖｆ）、微核细胞（ ＭＮＣ） 率、微核（ ＭＮ） 率均已显著增加（Ｐ＜ ０－０１）。ＨＰＲＴＶｆ、ＭＮＣ率、ＭＮ 率与累积剂量间均可拟合成对数回归方程：Ｙ＝ ａ＋ ｂｌｎＸ。在总累积剂量近似相等条件下，ＨＰＲＴ Ｖｆ、ＭＮ率与剂量率之间的关系均可用函数Ｙ＝ ａ ＋ ｂｌｎＸ 表示。ＨＰＲＴ Ｖｆ 与ＭＮ 率间存在线性相关。结论 ＨＰＲＴ基因位点对晚期混合裂变产物内照射非常敏感，有明显的剂量效应关系。ＨＰＲＴ 基因突变检测可望成为评估电离辐射损伤的生物剂量计。

Objective\ The probability of mutations at HPRT loci used as a biological dosimeter was studied. Methods With the technique of multinuclear cell and cytokinesis\|block micronucleus (CBMN) method,the relationships between mutations at HPRT loci,micronucleus and accmulative doses and dose\|rates were studied. Results On the first day after intravenous injection of late fission products(accumulative dose 1.73cSv),by comparison with the control group,the HPRT variant frequencies,micronucleate cell frequencies and micronucleus frequencies increased significantly( P <0 01).There existed relationships between variant frequencies at HPRT locus,micronuclear cell frequencies,micronucleus frequencies and accumulative doses,which could be described by the following regression equation:Y=a+blnX,respectively.At the same accumulative dose,both the relationships between HPRT variant frequencies,micronucleus frequencies and dose\|rates could be expressed by the logarithmic regression equation:Y=a+blnX.A good linear relationship between HPRT variant frequencies and micronucleus frequencies was observed. Conclusion HPRT gene locus is an endpoint very sensitive to injurious effects resulting from late fission products and has a good dose\|response relationship.\;