Departament de Ciència Animal i dels Aliments, Facultat de Veterinària, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona, 08193, Spain.
Robinson Research Institute, School of Paediatrics and Reproductive Health, The University of Adelaide, Adelaide, South Australia, 5005, Australia; Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, 5005, Australia; Australian Research Council Centre of Excellence for Nanoscale BioPhotonics and Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, South Australia, 5005, Australia.
Anim Reprod Sci. 2019 Mar;202:49-57. doi: 10.1016/j.anireprosci.2019.01.007. Epub 2019 Jan 25.
In vitro embryo production depends on oocyte competence, which is acquired during folliculogenesis, involving cytoplasmic and nuclear processes. In vitro maturation (IVM) induces spontaneous resumption of meiosis, preventing full competence acquisition. The incorporation of a pre-IVM phase with supplementation with C-type natriuretic peptide (CNP) and 3-Isobutyl-1-methylxanthine (IBMX) was used with the aim of improving developmental competence of cattle oocytes. In a preliminary experiment, COCs were cultured with increasing CNP concentrations and nuclear stage assessment was performed. Supplementation with both 100 and 200 nM CNP resulted in more germinal vesicle (GV) arrest at 6 h of culture than those in the control group (79.3%, 76.4% and 59.2%, respectively). In a second experiment, use of 100 nM CNP plus 500 μM IBMX resulted in retention of more oocytes in the GV stage (92.0%) at 6 h of culture compared to supplementation with either CNP or IBMX alone (74.8% and 86.7%, respectively). A subsequent assessment of the effect of the pre-IVM system (6-h of culture with CNP plus IBMX), followed by 20-h of IVM, with comparison to the control at 24-h of IVM was performed. Blastocyst development rate was greater after the pre-IVM phase (45.1% compared with 34.5%). The inclusion of the pre-IVM phase also resulted in an enhanced mitochondrial activity in matured oocytes and sustained integrity of transzonal projections for longer after IVM. In conclusion, CNP and IBMX function synergistically to arrest meiosis in cattle oocytes during a pre-IVM phase, which improves cumulus-oocyte communication and embryo development.
体外胚胎生产依赖于卵母细胞的能力，这种能力是在卵泡发生过程中获得的，涉及细胞质和核过程。体外成熟（IVM）诱导减数分裂的自发恢复，阻止完全获得能力。在 IVM 之前加入一个阶段，并补充 C 型利钠肽（CNP）和 3-异丁基-1-甲基黄嘌呤（IBMX），旨在提高牛卵母细胞的发育能力。在一个初步实验中，COCs 用递增浓度的 CNP 培养，并进行核阶段评估。与对照组相比，补充 100 和 200 nM CNP 导致更多的卵母细胞在 6 小时的培养中处于生发泡期（GV）阻滞（分别为 79.3%、76.4%和 59.2%）。在第二个实验中，使用 100 nM CNP 加 500 μM IBMX 导致更多的卵母细胞在 6 小时的培养中保留在 GV 期（92.0%），与单独补充 CNP 或 IBMX 相比（分别为 74.8%和 86.7%）。随后评估了预 IVM 系统（用 CNP 和 IBMX 培养 6 小时）的效果，然后在 IVM 20 小时后与 IVM 24 小时的对照组进行比较。在预 IVM 阶段后，囊胚发育率更高（45.1%比 34.5%）。预 IVM 阶段的加入还导致成熟卵母细胞中线粒体活性增强，并在 IVM 后更长时间内保持透明带突起的完整性。总之，CNP 和 IBMX 在预 IVM 阶段协同作用，阻止牛卵母细胞的减数分裂，从而改善卵丘-卵母细胞的通讯和胚胎发育。
