Inoue M, Kurihara T, Yamashita M, Tatsumi K
Medical Research Institute, Kanazawa Medical University, Ishikawa, Japan.
Mutat Res. 1993 Aug;294(2):179-86. doi: 10.1016/0921-8777(93)90026-d.
DNA damage and its related effects were quantitatively measured in germ cells at various meiotic and postmeiotic stages in male mice treated with methyl methanesulfonate (MMS). Unscheduled DNA synthesis (UDS) took place most efficiently in germ cell stages from middle to late spermatocytes at the time of MMS treatment, and essentially no UDS was detected in the stages from late spermatid to maturing spermatozoa, suggesting the absence of DNA repair in late spermatids and maturing spermatozoa. Late spermatids and immature spermatozoa were, on the other hand, most sensitive to MMS in producing DNA single-strand breaks (SSB) as well as chromosome aberrations in eggs fertilized by the treated males. The storage of the spermatozoa in the reproductive tract appeared to enhance the production of SSB. DNA damages induced by MMS should cause various genetic effects during the postmeiotic stages and maturation of spermatozoa through mechanisms not related to excision repair.
在用甲磺酸甲酯（MMS）处理的雄性小鼠中，对处于减数分裂和减数分裂后各个阶段的生殖细胞中的DNA损伤及其相关效应进行了定量测量。在MMS处理时，非预定DNA合成（UDS）在精母细胞从中期到后期的生殖细胞阶段最为有效，而在精子细胞后期到成熟精子阶段基本未检测到UDS，这表明精子细胞后期和成熟精子中不存在DNA修复。另一方面，精子细胞后期和未成熟精子在产生DNA单链断裂（SSB）以及受处理雄性所授精的卵子中的染色体畸变方面对MMS最为敏感。精子在生殖道中的储存似乎会增强SSB的产生。MMS诱导的DNA损伤应通过与切除修复无关的机制在减数分裂后阶段和精子成熟过程中引起各种遗传效应。
