Mailhes J B, Marchetti F, Aardema M J
Department of Obstetrics and Gynecology, Louisiana State University Medical Center, Shreveport 71130.
Mutat Res. 1993 Aug;300(3-4):155-63. doi: 10.1016/0165-1218(93)90047-h.
The in vivo mouse oocyte assay provides a useful system for studying both structural and numerical cytogenetic abnormalities induced by chemicals in mammalian germ cells. As part of the development of this assay for investigating chemically-induced numerical chromosome changes, the experimental and biological variables that can influence the outcome of the assay are being determined. In this study, we investigated the effect of griseofulvin (GF) administered by oral gavage on the induction of meiotic delay as measured by ovulated metaphase I (MI) oocytes and the induction of aneuploidy in metaphase II (MII) oocytes. The results indicate that GE significantly increased the frequencies of oocytes blocked in MI and of hyperploid MII oocytes compared to controls. The biological fate of delayed MI oocytes was investigated by harvesting oocytes at different times post treatment. With increasing harvest times, the frequency of MI oocytes decreased and, unexpectedly, the frequency of hyperploid MII oocytes also decreased. This suggests that some MI oocytes can overcome the GF-induced meiotic block, form a normal meiotic spindle, and progress to metaphase II as normal MII oocytes. The significance of these findings for the design and interpretation of in vivo mouse oocyte studies is discussed.
体内小鼠卵母细胞试验为研究化学物质在哺乳动物生殖细胞中诱导的结构和数量细胞遗传学异常提供了一个有用的系统。作为该试验开发的一部分，用于研究化学诱导的染色体数量变化，正在确定可能影响试验结果的实验和生物学变量。在本研究中，我们研究了通过口服灌胃给予灰黄霉素（GF）对减数分裂延迟诱导的影响，减数分裂延迟通过排卵的中期I（MI）卵母细胞来衡量，以及对中期II（MII）卵母细胞非整倍体诱导的影响。结果表明，与对照组相比，GF显著增加了MI期阻滞的卵母细胞频率和超倍体MII期卵母细胞频率。通过在处理后不同时间收获卵母细胞来研究延迟的MI期卵母细胞的生物学命运。随着收获时间的增加，MI期卵母细胞的频率降低，出乎意料的是，超倍体MII期卵母细胞的频率也降低。这表明一些MI期卵母细胞可以克服GF诱导的减数分裂阻滞，形成正常的减数分裂纺锤体，并作为正常的MII期卵母细胞进入中期II。讨论了这些发现对体内小鼠卵母细胞研究的设计和解释的意义。
