低剂量^（147）Pm内照射对精子DNA链修复的刺激效应

Stimulative effect of low dose^(147)Pm irradiation on DNA repair of germ cells in spermiogenic stages

作者设计用碱性淋洗技术探讨了小鼠受低剂量１４７Ｐｍ内污染时对精子ＤＮＡ链修复的刺激效应。动物预先在睾丸内注入３Ｈ－ＴｄＲ，用以标记精子ＤＮＡ，从标记到采集精子的时间固定为３６天，正好为ＢＡＬＢ／ｃ小白鼠雄性生殖细胞的一个发育周期．从摄入１４７Ｐｍ到采集精子的时间则固定在１２天，因这时小白鼠精子ＤＮＡ链断裂的洗脱量最大，待精子被溶胞液溶破后，加入淋洗液，调节蠕动泵流量定时收集标本，用液闪装置测量膜上标本和膜下各收集标本的放射性活度，从而判断各标本中ＤＮＡ的量。研究结果发现，当机体内污染低剂量１４７Ｐｍ在０．１８５ｋＢｑ／ｇ时，此时的膜上ＤＮＡ存留率呈现升高，显著高于相应对照组，表明低剂量裂片１４７Ｐｍ内照射对精子ＤＮＡ链修复的刺激效应。

Stimulative effect of low dose irradiation with 147pm on DNA repair of germ cells in spermiogenic stages was studied by alkaline elution technique.Male BALB/c mice were given intratesticular injection of 3H-TdR in advance to label spermatid DNA. After a period of 36 days of labelling, which was coincident with a developmental cycle for the germ cells, spermatozoa were sampled. The period from intraperitoneal injection of 147Pm to spermatozoa sampling was 12 days.When sperm cells were lysed, 30 ml eluant was added in, then the flowrate was adjusted by the pumping speed. Finally, the DNA in filters and bottles were determined by radioactivity of labelled nuclides with a Beckman liquid scintillation device. Results showed that after small dose of irradiation with 0.185kBq/g of 147Pm,the retention of sperm DNA on the filter was increased, which was considerably higher than that in the control group. This indicates that low level radiation from 147Pm has a tendency to stimulate the capacity of DNA repair in spermiongenic stages.