Department of Physiology, Faculty of Veterinary Science, University of Murcia, Murcia, Spain.
Theriogenology. 2012 Sep 15;78(5):1126-39.e1. doi: 10.1016/j.theriogenology.2012.05.009. Epub 2012 Jul 3.
The cortical reaction induces changes at the egg's Zona pellucida (ZP), perivitelline space and/or oolemma level, blocking polyspermic fertilization. We studied the timing of sperm penetration and cortical reaction in pig oocytes matured under different conditions and inseminated with different boars. Immature (germinal vesicle stage) and in vitro matured (IVM) (metaphase II stage) oocytes were inseminated and results assessed at different hours post insemination. Penetrability and polyspermy rates increased with gamete coincubation time and were higher in IVM oocytes. A strong boar effect was observed in IVF results. Cortical reaction (assessed as area occupied by cortical granules) and galactose-β(1-3)-Nacetylgalactosamine residues on ZP (area labeled by peanut agglutinin lectin, PNA) were assessed in IVM and in vivo matured (IVV) oocytes at different hours post insemination. After maturation, IVM and IVV oocytes displayed similar area occupied by cortical granules and it decreased in fertilized oocytes compared to unfertilized ones. Cortical reaction was influenced by boar and was faster in polyspermic than in monospermic oocytes, and in IVM than in IVV oocytes. The outer ZP of inseminated oocytes appeared stained by PNA and the labeled area increased along with gamete coculture time. This labeling was also observed after insemination of isolated ZP, indicating that this modification in ZP carbohydrates is not induced by cortical reaction. The steady and maintained cortical reaction observed at 4 to 5 h post insemination in IVV monospermic oocytes might reflect the physiological time course of this important event in pigs. Both maturation conditions and boar affect cortical granules release.
皮质反应诱导卵的透明带（ZP）、卵周隙和/或卵母细胞膜水平的变化，从而阻止多精受精。我们研究了在不同条件下成熟的猪卵母细胞在与不同公猪授精时的精子穿透和皮质反应的时间。不成熟（核膜期）和体外成熟（IVM）（中期 II 期）卵母细胞进行授精，并在授精后不同时间评估穿透率和多精率。穿透率和多精率随着配子共培养时间的增加而增加，并且在 IVM 卵母细胞中更高。在 IVF 结果中观察到强烈的公猪效应。在不同时间点评估 IVM 和体内成熟（IVV）卵母细胞的皮质反应（评估为皮质颗粒占据的面积）和 ZP 上的半乳糖-β（1-3）-N-乙酰半乳糖胺残基（花生凝集素 PNA 标记的区域）。成熟后，IVM 和 IVV 卵母细胞的皮质颗粒占据面积相似，与未受精的卵母细胞相比，受精的卵母细胞减少。皮质反应受到公猪的影响，多精受精的卵母细胞比单精受精的卵母细胞反应更快，IVM 卵母细胞比 IVV 卵母细胞更快。被授精的卵母细胞的透明带外部似乎被 PNA 染色，并且标记区域随着配子共培养时间的增加而增加。这种标记也在分离的 ZP 授精后观察到，表明 ZP 碳水化合物的这种修饰不是由皮质反应引起的。在 IVV 单精受精的卵母细胞中，在授精后 4 至 5 小时观察到的稳定和持续的皮质反应可能反映了这一重要事件在猪中的生理时间过程。成熟条件和公猪都会影响皮质颗粒的释放。
