College of Animal Science and Technology, Inner Mongolia University for the Nationalities, 536 West Huolinhe Street, Tongliao, 028000, Inner Mongolia, People's Republic of China.
Sci Rep. 2020 Oct 26;10(1):18213. doi: 10.1038/s41598-020-75354-5.
The present study aimed to evaluate the effects of C-type natriuretic peptide (CNP) on meiotic arrest and developmental competence of bovine oocyte derived from follicles of different sizes. Collected immature cumulus-oocyte complexes from small follicles (< 3 mm) and medium follicles (3-8 mm) were cultured for 6 h in basal medium supplementated without or with 200 nM CNP. We observed that CNP effectively sustained meiotic arrest at germinal vesicle stage in in vitro cultured bovine oocytes from follicles of different sizes. Moreover, CNP treatment significantly improved the levels of cGMP in both cumulus cells and oocytes, as well as the levels of cAMP in oocytes regardless of follicle size. Based on the above results, we tested the effect of a novel in vitro maturation (IVM) system based on CNP-pretreatment, including a pre-IVM phase for 6 h using 200 nM CNP, followed by a extended IVM phase for 28 h, on developmental competence of bovine oocyte derived from small follicles (< 3 mm) and medium follicles (3-8 mm) compared to standard IVM system. The results showed that athough the novel IVM system based on CNP-pretreatment enhanced the developmental potencial of oocytes obtained from large follicles, but had no effect on the developmental comptence of oocytes obtained from small follicles.
本研究旨在评估 C 型利钠肽（CNP）对不同大小卵泡来源的卵母细胞减数分裂阻滞和发育能力的影响。从小卵泡（<3mm）和中卵泡（3-8mm）收集未成熟的卵丘-卵母细胞复合物，在基础培养基中培养 6 小时，不添加或添加 200nM CNP。我们观察到 CNP 可有效维持不同大小卵泡来源的体外培养卵母细胞的减数分裂阻滞在生发泡期。此外，无论卵泡大小如何，CNP 处理均可显著提高卵丘细胞和卵母细胞中环磷酸鸟苷（cGMP）的水平，以及卵母细胞中环磷酸腺苷（cAMP）的水平。基于上述结果，我们测试了一种基于 CNP 预处理的新型体外成熟（IVM）系统的效果，包括使用 200nM CNP 进行 6 小时的预 IVM 阶段，然后进行 28 小时的延长 IVM 阶段，与标准 IVM 系统相比，该系统对从小卵泡（<3mm）和中卵泡（3-8mm）获得的卵母细胞的发育能力的影响。结果表明，虽然基于 CNP 预处理的新型 IVM 系统增强了大卵泡来源卵母细胞的发育潜力，但对小卵泡来源卵母细胞的发育能力没有影响。
