卵丘细胞凋亡与增殖对牛卵母细胞体外发育的影响

 【目的】探讨卵丘-卵母细胞复合体（COCs）形态、卵丘细胞凋亡与增殖状态和卵母细胞发育能力之间的相关性。【方法】根据卵胞质均匀程度和卵丘细胞层数等形态指标，对所挑选的未成熟COCs进行分组，随后利用体外受精技术和TUNEL技术，并结合流式细胞仪，评价各组COCs的体外发育能力及其卵丘细胞凋亡和细胞周期差异。【结果】 与包被5层以上致密卵丘且卵胞质均质的COCs相比，具有2—5层轻度扩散卵丘与颗粒化卵质特征的COCs显示较好的后续胚胎发育潜力、较高的卵丘细胞凋亡程度和较低的G2-M期细胞比率。【结论】 卵丘细胞凋亡程度与未成熟卵母细胞发育潜能呈正相关；COCs形态、卵丘细胞凋亡或者G2-M期细胞比率指标可以用来指示未成熟卵母细胞的发育潜力。

Effect of Cumulus Cell Apoptosis and Proliferation on Bovine Oocyte Development in vitro

【Objective】The aim of this study was to investigate the relationship between the appearance of bovine cumulus-oocyte complexes (COCs) and apoptosis or proliferation of cumulus cells and oocyte developmental capacity.【Method】Cumulus-oocyte complexes (COCs) were selected and classified into 4 groups according to oocyte cytoplasm and cumulus status. Apoptosis and cell cycle of cumulus cells from each group were detected by TUNEL staining combined with flow cytometry. Developmental competence was evaluated by development rates at different stages following in vitro fertilization.【Result】Results indicated that, compared to the COCs with five or more layers of cumulus cells and homogeneous ooplasm, that with two-five layers of cumulus cells and slight granulation of the ooplasm showed the highest TUNEL positive ratio of cumulus cells and subsequent embryo developmental potential.【Conclusion】It indicated that apoptosis in cumulus cells is associated with improved developmental potential in bovine immature oocytes, and it makes good markers for embryo development of COCs morphology, apoptosis and the ratio to the stage of G2-M in cumulus cells.