Division of Applied Life Science (BK21 Program), Graduate School of Gyeongsang National University, Jinju, Republic of Korea.
Theriogenology. 2013 Dec;80(9):1117-23. doi: 10.1016/j.theriogenology.2013.08.015. Epub 2013 Sep 29.
Oocyte quality is a key factor affecting success of in vitro embryo production in cattle. Improving the microenvironment of oocytes during in vitro maturation (IVM) can increase developmental rate and embryo quality. Therefore, the objective was to determine whether denuded oocytes (DO) affect embryo development and ultrastructure of the zona pellucida (ZP) in in vitro matured bovine oocytes. Intact immature cumulus-oocytes complexes (COC) obtained from a local abattoir or by ovum pick-up (OPU) were cocultured with and without abattoir-obtained DO at a COC:DO ratio of 1:5. After IVM, DO were removed and intact DO were either fertilized or observed by scanning electron microscopy. Blastocyst quality was evaluated using a TUNEL assay. The ZP pore size decreased after IVM in COC + DO coculture, regardless of their origin (OPU, 310.5 ± 92.5 vs. 428.9 ± 148.5 nm; abattoir, 317.5 ± 68.5 vs. 358.9 ± 128.5 nm; P < 0.05; mean values ± standard deviation). Moreover, the number of ZP pores in OPU COC + DO and COC + DO was greater than those in OPU COC and COC (control) groups (56 ± 4 and 55 ± 7 vs. 50 ± 6 and 42 ± 4; P < 0.05). The rate of blastocyst development in COC + DO and OPU COC + DO groups was greater those in control and OPU COC groups (36.6% and 55.5% vs. 28.1% and 40.0%; P < 0.05). Moreover, the total cell numbers of blastocysts in COC + DO group exceeded that of control (132.91 ± 30.90 vs. 115.44 ± 24.95; P < 0.05), with no significant between OPU COC + DO and OPU COC groups (139.31 ± 42.51 vs. 137.00 ± 61.34). In conclusion, in vitro embryo development competence and quality improved when oocytes were cocultured with DO. Furthermore, there more, but smaller, ZP pores.
卵母细胞质量是影响牛体外胚胎生产成功的关键因素。在体外成熟（IVM）过程中改善卵母细胞的微环境可以提高胚胎的发育率和质量。因此，本研究旨在确定裸卵（DO）是否会影响体外成熟牛卵母细胞的胚胎发育和透明带（ZP）的超微结构。从当地屠宰场或卵母细胞抽吸（OPU）获得的完整不成熟卵丘-卵母细胞复合物（COC）与屠宰场获得的 DO 以 1:5 的 COC:DO 比例进行共培养。IVM 后，去除 DO，并对完整的 DO 进行受精或通过扫描电子显微镜观察。通过 TUNEL 测定评估囊胚质量。在 COC+DO 共培养中，无论 DO 来源（OPU，310.5±92.5 与 428.9±148.5nm；屠宰场，317.5±68.5 与 358.9±128.5nm；P<0.05），ZP 孔大小在 IVM 后均减小。此外，与 OPU COC 和 COC（对照）组相比，OPU COC+DO 和 COC+DO 的 ZP 孔数量更多（56±4 和 55±7 与 50±6 和 42±4；P<0.05）。COC+DO 和 OPU COC+DO 组的囊胚发育率高于对照和 OPU COC 组（36.6%和 55.5%与 28.1%和 40.0%；P<0.05）。此外，COC+DO 组的囊胚总细胞数高于对照组（132.91±30.90 与 115.44±24.95；P<0.05），但与 OPU COC+DO 和 OPU COC 组之间无显著差异（139.31±42.51 与 137.00±61.34）。总之，当卵母细胞与 DO 共培养时，体外胚胎发育能力和质量提高，ZP 孔更多，但更小。
