The present study was conducted to evaluate the effects in vitro on oocyte mitochondrial function of C-type natriuretic peptide (CNP) when treatments were imposed before in vitro maturation (IVM). Immature oocytes were either directly matured in vitro for 24 h (Control, no pre-IVM), or cultured in basic medium not supplemented or supplemented with CNP (100 nM) (Control pre-IVM and CNP pre-IVM, respectively) for 6 h, followed by IVM for 24 h. The results indicated treatment with CNP before IVM affected patterns of distribution of mitochondria, increased the mitochondrial content, membrane potential, and decreased the ROS content in cattle oocytes before and after IVM. Furthermore, treatment of immature cattle oocytes with CNP before IVM induced marked increases in the relative abundance of mRNA transcripts and proteins related to mitochondria development and antioxidative defense mechanisms. Treatment with CNP before oocyte IVM also resulted in an enhanced relative abundance of sirtuin-1 (SIRT1) mRNA transcript in cattle oocytes. Taken together, these results provide evidence that treatment of cattle oocytes with CNP before IVM improved mitochondrial function and antioxidant defense mechanisms in cattle oocytes. Findings in the present study provide insights into the potential mechanisms by which CNP has positive effects on oocyte cytoplasmic organelles, specifically mitochondria.

本研究旨在评估在体外成熟 (IVM)前进行治疗时 C 型利钠肽 (CNP) 对卵母细胞线粒体功能的体外影响。未成熟的卵母细胞在体外直接成熟24 小时（对照，无 pre-IVM），或在未补充或补充 CNP（100 nM）（分别为对照 pre-IVM 和 CNP pre-IVM）的基础培养基中培养 6 小时，然后在 IVM 中培养 24 小时. 结果表明，在 IVM 前用 CNP 处理影响了线粒体分布模式，增加了 IVM 前后牛卵母细胞的线粒体含量和膜电位，并降低了 ROS 含量。此外，在 IVM 之前用 CNP 处理未成熟的牛卵母细胞会显着增加与线粒体发育和抗氧化防御机制相关的 mRNA 转录物和蛋白质的相对丰度。在卵母细胞 IVM 前用 CNP 处理也导致Sirtuin-1（SIRT1) 牛卵母细胞中的 mRNA 转录物。总之，这些结果提供了证据，表明在 IVM 之前用 CNP 处理牛卵母细胞可以改善牛卵母细胞的线粒体功能和抗氧化防御机制。本研究的结果提供了对 CNP 对卵母细胞细胞质细胞器（特别是线粒体）产生积极影响的潜在机制的见解。