The aim of this study was to assess the presence and distribution of apoptosis in porcine cumulus-oocyte complexes (COCs) and its relations with COC morphology and developmental competence. The COCs were obtained from slaughterhouse ovaries, classified into A1 (top category), A2, B1, B2, C, and D based on their morphology. A1, A2, and B1 were matured and fertilized in vitro, and blastocyst rate was compared among them. Before and after in vitro maturation (IVM), annexin-V staining, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays were performed to assess early and late apoptosis, respectively. There was a significant increase in both annexin-V (+) oocytes and TUNEL (+) cumulus cells as morphology further deteriorated. There were no statistical differences regarding annexin-V (+) oocytes within immature and post-IVM COCs, but TUNEL (+) oocytes were only observed in post-IVM COCs. Early and late apoptosis was detected in cumulus cells of all categories of immature and post-IVM COCs. However, the difference was only significant for annexin-V (+). There were no significant differences in embryo development. Therefore, apoptosis increases as the morphological features of the immature COCs decrease. In conclusion, the selection of COCs from Categories A1, A2, and B1 may be used as a selection criterion for in vitro development.

中文翻译：

---

猪卵-卵母细胞复合物中的细胞凋亡：与它们的形态和发育能力的关系。

这项研究的目的是评估猪卵丘卵母细胞复合物（COC）中细胞凋亡的存在和分布及其与COC形态和发育能力的关系。COC从屠宰场卵巢中获得，根据其形态分为A1（顶级），A2，B1，B2，C和D。A1，A2和B1在体外成熟并受精，并比较它们的囊胚发生率。进行体外成熟（IVM）之前和之后，膜联蛋白-V染色和末端脱氧核苷酸转移酶dUTP缺口末端标记（TUNEL）分析分别评估了早期和晚期凋亡。随着形态进一步恶化，膜联蛋白-V（+）卵母细胞和TUNEL（+）卵丘细胞均显着增加。在未成熟和IVM后的COC中，膜联蛋白-V（+）卵母细胞没有统计学差异，但仅在IVM后的COC中观察到TUNEL（+）卵母细胞。在所有未成熟IVM和后IVM COC的卵丘细胞中均检测到早期和晚期凋亡。但是，差异仅对膜联蛋白-V（+）有意义。胚胎发育没有显着差异。因此，随着未成熟COCs的形态特征降低，凋亡增加。总之，从类别A1，A2和B1中选择COC可以用作体外发育的选择标准。胚胎发育没有显着差异。因此，随着未成熟COCs的形态特征降低，凋亡增加。总之，从类别A1，A2和B1中选择COC可以用作体外发育的选择标准。胚胎发育没有显着差异。因此，随着未成熟COCs的形态特征降低，凋亡增加。总之，从类别A1，A2和B1中选择COC可以用作体外发育的选择标准。