Laboratory of Veterinary Embryology and Biotechnology, Veterinary Medical Center and College of Veterinary Medicine, Chungbuk National University, Cheongju, Republic of Korea.
Institute of Stem Cell & Regenerative Medicine, Chungbuk National University, Cheongju, Republic of Korea.
Biol Reprod. 2019 Jul 1;101(1):63-75. doi: 10.1093/biolre/ioz066.
Growth differentiation factor 8 (GDF8), also known as myostatin, is a member of the transforming growth factor-β (TGF-β) family and has been identified as a strong physiological regulator of muscle differentiation. Recently, the functional role of GDF8 in reproductive organs has received increased interest following its detection in the human placenta and uterus. To investigate the effects of GDF8 during porcine oocyte in vitro maturation (IVM), we assessed the quality of matured oocytes. Furthermore, we investigated the specific gene transcription and protein activation levels in oocytes and cumulus cells after IVM and subsequent embryonic development after in vitro fertilization and parthenogenetic activation. Prior to these experiments, the concentration of GDF8 in porcine follicular fluid was determined. During the entire IVM period, 1.3 ng/mL GDF8 and its signaling inhibitor SB431542 (SB) at 5 μM were added as control, SB, SB + GDF8, and GDF8 groups, respectively. Our results demonstrate that supplementation with GDF8 during porcine oocyte IVM enhanced both meiotic and cytoplasmic maturation, with altered transcriptional patterns, via activation of Sma- and Mad-related protein 2/3 (SMAD2/3). Using the pharmacological inhibitor SB431542, we demonstrated that inhibition of GDF8-induced Smad2/3 signaling reduces matured oocyte quality. In conclusion, for the first time, we demonstrated paracrine factor GDF8 in porcine follicular fluid in vivo. Furthermore, we showed that GDF8 supplementation improved mature oocyte quality by regulating p38 mitogen-activated protein kinase phosphorylation and intracellular glutathione and reactive oxygen species levels during porcine IVM.
生长分化因子 8（GDF8），也称为肌肉生长抑制素，是转化生长因子-β（TGF-β）家族的成员，已被确定为肌肉分化的强大生理调节剂。最近，GDF8 在人胎盘和子宫中的检测结果引起了人们对其在生殖器官中的功能作用的兴趣增加。为了研究 GDF8 在猪卵母细胞体外成熟（IVM）过程中的作用，我们评估了成熟卵母细胞的质量。此外，我们研究了 IVM 后卵母细胞和卵丘细胞的特定基因转录和蛋白激活水平，以及体外受精和孤雌激活后的胚胎发育。在进行这些实验之前，确定了猪卵泡液中的 GDF8 浓度。在整个 IVM 期间，添加了 1.3ng/mL 的 GDF8 和 5μM 的其信号抑制剂 SB431542（SB），作为对照、SB、SB+GDF8 和 GDF8 组。我们的结果表明，在猪卵母细胞 IVM 期间添加 GDF8 可通过激活 Smad2/3 来增强减数分裂和细胞质成熟，并改变转录模式。使用药理学抑制剂 SB431542，我们证明抑制 GDF8 诱导的 Smad2/3 信号会降低成熟卵母细胞的质量。总之，我们首次在体内证明了猪卵泡液中的旁分泌因子 GDF8。此外，我们表明，通过调节猪 IVM 过程中的 p38 丝裂原激活蛋白激酶磷酸化和细胞内谷胱甘肽和活性氧水平，GDF8 补充可改善成熟卵母细胞的质量。
