NOCODAZOLE SENSITIVITY, AGE-RELATED ANEUPLOIDY, AND ALTERATIONS IN THE CELL-CYCLE DURING MATURATION OF MOUSE OOCYTES
NOCODAZOLE SENSITIVITY, AGE-RELATED ANEUPLOIDY, AND ALTERATIONS IN THE CELL-CYCLE DURING MATURATION OF MOUSE OOCYTES
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DOI：
10.1159/000132871
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发表时间：
1989-01-01
期刊：
影响因子：
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通讯作者：
BOLL, I
中科院分区：
文献类型：
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作者：
EICHENLAUBRITTER, U;BOLL, I
为了检测年龄相关的纺锤体形成和功能的变化，我们检查了从年轻（2-4个月）和老年（> 9个月）非发情CBA/Ca小鼠获得的体外成熟卵母细胞。对处理后的细胞进行抗微管蛋白免疫荧光的观察显示，老年雌性的卵母细胞比年轻动物的卵母细胞在第一次成熟分裂中进展得更快。它们也更容易发生不分离，如在中期II时C带细胞中非整倍性水平显著较高所示。还研究了卵母细胞从微管抑制剂诺考达唑处理中恢复的能力，以及药物对纺锤体完整性和染色体分离的影响。在两个年龄组中，用10 μ M诺考达唑处理中期I卵母细胞引起快速和完全的微管解聚和染色体分散。恢复后，两个年龄组的卵母细胞都能够重建纺锤体，通过后期进行，并挤出第一极体。然而，诺考达唑处理导致非整倍体的急剧增加。出乎意料的是，超倍体的相对上升是更大的卵母细胞从年轻的小鼠比那些从老年小鼠，因此，超倍体中期II细胞的绝对百分比是相似的，在两个年龄组药物治疗后。同时，诺考达唑暴露消除或至少减少了对照中存在的细胞周期和后期触发因子的内在差异（例如，来自老年女性的卵母细胞中染色体分离的早期开始）。缩短了所有卵母细胞染色体分离前纺锤体形成的时间。因此，我们的研究表明，在卵母细胞的成熟过程中的时间差异，特别是，染色体分离发生在老年女性的卵母细胞中的二价体对齐的时间缩短，是主要负责与年龄相关的非整倍体的上升。没有迹象表明：（1）来自老年哺乳动物的卵母细胞的纺锤体比来自年轻个体的卵母细胞的纺锤体更不稳定或更容易受到干扰，或者（2）单价体数量的增加使来自老年哺乳动物的卵母细胞特别容易不分离。
To detect age-related alterations in the formation and function of the spindle apparatus, we examined in vitro maturing oocytes obtained from young (2-4 mo) and aged (> 9 mo) diestrous CBA/Ca mice. Observation of cells processed for antitubulin immunofluorescence revealed that oocytes from aged females progress faster through first maturation division than those from young animals. They are also more prone to nondisjunction, as shown by a significantly higher level of aneuploidy in C-banded cells arrested at metaphase II. The ability of oocytes to recover from treatment with a microtubule inhibitor, nocodazole, and the effect of the drug on spindle integrity and chromosome segregation were also studied. In both age groups, treatment of metaphase I oocytes with 10 .mu.M nocodazole caused rapid and complete microtubule depolymerization and chromosome scattering. Upon recovery, oocytes from both age groups were able to reestablish a spindle apparatus, proceed through anaphase, and extrude a first polar body. However, nocodazole treatment led to a dramatic increase of aneuploidy. Unexpectedly, the relative rise in hyperploids was greater in oocytes from young mice than in those from aged mice, so that the absolute percentage of hyperploid metaphase II cells was similar in both age groups after drug treatment. Concomitantly, nocodazole exposure abolished or, at least, diminished intrinsic differences in the cell cycle and anaphase trigger present in the controls (e.g., the earlier onset of chromosome separation in oocytes from aged females). It shortened the period available for spindle formation before chromosome segregation in all oocytes. Therefore, our study implies that temporal differences in the progression of oocytes through maturation, in particular, the shortening of the time available for alignment of bivalents before chromosome separation occurs in oocytes of old females, are mainly responsible for age-related rises in aneuploidy. There is no indication that (1) the spindle apparatus of oocytes from aged mammals is more labile or susceptible to disturbances than the spindle apparatus of oocytes from young individuals or that (2) an increase in the number of univalents makes oocytes from aged mammals particularly prone to nondisjunction.