X射线诱发雄性小鼠生殖细胞染色体畸变及显性致死突变研究

2.0 Gy X射线照射雄鼠不同发育阶段的生殖细胞与超数排卵处理的正常雌鼠交配,制备受精卵染色体标本。结果表明;雄性原核染色体畸变量以精细胞>成熟精子>精母细胞>精原细胞的顺序发生,其中前二者与自身正常对照比较,差异非常显著(p<0.01),与国外有关报道相一致。照后170d的精原细胞易位,明显高于正常对照,而且与照后140 d观察的显性致死突变明显相关。实验证实用受精卵技术检测减数分裂后染色体损伤是良好的实验手段,而观察精原干细胞易位,用精母细胞实验更理想。

STUDIES ON CHROMOSOMAL ABERRATIONS AND DOMINANT LETHAL MUTATIONS INDUCED BY X IRRADIATION IN GERM CELLS OF MALE MICE

After male mice irradiated by 2Gy X rays mated to normal virg- inal females superovulated with PMSG and HCG, pronuclei chromosome spreading of first-cleavage embryos were prepared and chromosomal aberrations of paternal pronucl- ei were observed, The results showed that the frequency of chromosomal aberrations was highest irradiated at spermatid stage among different stages of spermatogenesis. The sequency of radiosensitivity in spermatogenesis was as follows: spermatid>mature sperm>spermatocyte>spermatogoniu and stem spermatogonium. The frequencies of paternal chromosomal aberrations resulted from irradiation at spermatids and mature sperms were significantly higher than that in control. The reciprocal translocations of stem spermatogonia induced by 2Gy X rays in those male mice were also examined in the preparations of diakinesis-metaphase I. The freqency of reciprocal translocations were 0.0429 per cell and significantly higher than that in control. The proportion of unbalanced gametes, resulting in lethal embry- os after fertilization, was 0.02145 to be predicted. At the same time, the dominant lethality induced by X rays in stem spermatogonia was measured, being 0.0371. The frequency of dead fetuses in irradiation group was about twice as in control. The reg- ression analysis was found that the reciprocal translocations was markedly related to the dominant lethality.