Somfai T, Kikuchi K, Kaneda M, Akagi S, Watanabe S, Mizutani E, Haraguchi S, Dang-Nguyen T Q, Inaba Y, Geshi M, Nagai T
National Institute of Livestock and Grassland Science, Ikenodai, Tsukuba, Ibaraki, Japan.
Anat Histol Embryol. 2011 Oct;40(5):335-44. doi: 10.1111/j.1439-0264.2011.01079.x. Epub 2011 May 4.
We investigated the frequencies of cytoskeletal anomalies in metaphase-II (M-II) and incompetent [arrested at an immature metaphase (IM) stage] porcine and bovine oocytes during in vitro maturation (IVM) in relation with ageing by immunostaining and confocal microscopy. In porcine oocytes, meiotic arrest at the IM stage was associated with abnormalities of cortical actin but not with abnormal spindles. Prolongation of IVM culture to 52 h did not affect microfilament and spindle abnormalities, but reduced the microfilament-rich area overlaying the spindle. Meiotic arrest of bovine oocytes at the IM stage was associated with degenerations of microfilaments, and the frequencies of abnormal spindles were also higher than those of M-II oocytes. Ageing of bovine oocytes (IVM for 30 h) did not affect cortical microfilaments but increased the frequency of spindle alterations in both M-II and IM bovine oocytes. These results suggest that, in both species, altered ability of oocytes to polymerize F-actin might be a possible reason for the failure of polar body extrusion during IVM. Also, there seem to be differences between the two species in the sensitivity of oocytes to suffer ageing-related spindle damages.
我们通过免疫染色和共聚焦显微镜研究了体外成熟（IVM）过程中，处于中期II（M-II）以及无能（停滞于未成熟中期（IM）阶段）的猪和牛卵母细胞中细胞骨架异常的频率与衰老的关系。在猪卵母细胞中，停滞于IM阶段的减数分裂与皮质肌动蛋白异常有关，但与纺锤体异常无关。将IVM培养延长至52小时不影响微丝和纺锤体异常，但减少了纺锤体上方富含微丝的区域。牛卵母细胞在IM阶段的减数分裂停滞与微丝退化有关，并且异常纺锤体的频率也高于M-II期卵母细胞。牛卵母细胞老化（IVM 30小时）不影响皮质微丝，但增加了M-II期和IM期牛卵母细胞中纺锤体改变的频率。这些结果表明，在这两个物种中，卵母细胞聚合F-肌动蛋白能力的改变可能是IVM过程中极体排出失败的一个可能原因。此外，这两个物种的卵母细胞对与衰老相关的纺锤体损伤的敏感性似乎存在差异。
