Developmental potential in bovine oocytes is related to cumulus-oocyte complex grade, calcium current activity, and calcium stores
Developmental potential in bovine oocytes is related to cumulus-oocyte complex grade, calcium current activity, and calcium stores
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DOI：
10.1095/biolreprod66.3.836
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发表时间：
2002-03-01
影响因子：
3.6
通讯作者：
Tosti, E
中科院分区：
文献类型：
--
作者：
Boni, R;Cuomo, A;Tosti, E
未成熟卵丘-卵母细胞复合体（COC）的形态学分类与其卵泡来源的闭锁程度非常相似，本研究采用体外受精或孤雌激活法对牛卵母细胞的发育潜能进行了测定，采用全细胞电压钳技术测定了COC的钙电流活性，采用显微荧光法测定了COC的胞浆内钙储备。COC分类考虑了一些积云和卵质特征，指定如下：A）存在清晰致密的积云和半透明的卵质，B）深色致密的积云和深色卵质，以及C）深色膨胀的积云和深色卵质。我们没有发现体外受精和孤雌激活的卵母细胞在卵裂率和囊胚生产方面的差异。两种方案均表明三种比较的COC类别之间存在显著差异。B-COCs具有最高的胚胎生产效率和最大的Ca 2+电流活性，而A-COCs则表现出相反的模式。C-COCs的形态特征介于A-和B-COCs之间，主要由闭锁和重度闭锁卵泡形成。在未成熟卵母细胞的情况下，A-COCs中的Ca 2+储存量显著大于Band C-COCs，在体外成熟卵母细胞的情况下，B-COCs中的Ca 2+储存量显著大于C-和A-COCs。这些结果表明，在牛1）考虑的卵母细胞分类的形态学标准与发育能力有关，2）未成熟卵母细胞中的质膜Ca 2+电流与发育潜力有关，3）钙储备与未成熟卵母细胞的形态质量和成熟卵母细胞的发育能力有关。
A morphological classification of the immature cumulus-oocyte complex (COC), which grossly resembled the atresia grade of its follicle source, was used in bovine oocytes to determine 1) the developmental potential by either in vitro fertilization or parthenogenetic activation, 2) the calcium current activity by whole-cell voltage clamp technique, and 3) the intracytoplasmic calcium stores by microfluorimetric evaluation. The COC classification took into account some cumulus and ooplasm features, designated as follows: A) presence of a clear and compact cumulus and translucent ooplasm, B) dark and compact cumulus and dark ooplasm, and C) dark and expanded cumulus and dark ooplasm. We found no difference between in vitro fertilization and parthenogenetically activated oocytes in terms of cleavage rate and blastocyst production. Both protocols indicated a significant variability between the three compared COC categories. The B-COCs showed the highest embryo production efficiency as well as the greatest Ca2+ current activity, whereas A-COCs showed an opposite pattern. The C-COCs, mostly attributed to atretic and heavily atretic follicles, showed morphological characteristics between those of A- and B-COCs. Stores of Ca2+ were significantly greater in A-COCs than in Band C-COCs in the case of immature oocytes, and greater in B-COCs than in C-and A-COCs in the case of in vitro-matured oocytes. These results demonstrate that in the bovine 1) the considered morphological criteria for oocyte classification are related to developmental competence, 2) plasma membrane Ca2+ current in the immature oocyte is related to developmental potential, and 3) calcium stores are related to morphological quality in immature oocytes and to developmental competence in mature oocytes.