College of Life Science, Northeast Agricultural University, Harbin, 150030, P.R. China.
Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an City, 271018, P.R. China.
Sci Rep. 2020 Feb 17;10(1):2782. doi: 10.1038/s41598-020-59709-6.
The developmental competence of IVM porcine oocytes is still low compared with that in their in vivo counterparts. Although many studies reported effects of glucose metabolism (GM) on oocyte nuclear maturation, few reported on cytoplasmic maturation. Previous studies could not differentiate whether GM of cumulus cells (CCs) or that of cumulus-denuded oocytes (DOs) supported oocyte maturation. Furthermore, species differences in oocyte GM are largely unknown. Our aim was to address these issues by using enzyme activity inhibitors, RNAi gene silencing and special media that could support nuclear but not cytoplasmic maturation when GM was inhibited. The results showed that GM in CCs promoted pig oocyte maturation by releasing metabolites from both pentose phosphate pathway and glycolysis. Both pyruvate and lactate were transferred into pig DOs by monocarboxylate transporter and pyruvate was further delivered into mitochondria by mitochondrial pyruvate carrier in both pig DOs and CCs. In both pig DOs and CCs, pyruvate and lactate were utilized through mitochondrial electron transport and LDH-catalyzed oxidation to pyruvate, respectively. Pig and mouse DOs differed in their CC dependency for glucose, pyruvate and lactate utilization. While mouse DOs could not, pig DOs could use the lactate-derived pyruvate.
与体内成熟的卵母细胞相比，IVM 猪卵母细胞的发育能力仍然较低。虽然许多研究报告了葡萄糖代谢 (GM) 对卵母细胞核成熟的影响，但很少有研究报告 GM 对细胞质成熟的影响。以前的研究无法区分卵丘细胞 (CCs) 的 GM 或去卵丘卵母细胞 (DOs) 的 GM 支持卵母细胞成熟。此外，物种间卵母细胞 GM 的差异在很大程度上尚不清楚。我们的目的是通过使用酶活性抑制剂、RNAi 基因沉默以及特殊的培养基来解决这些问题，当 GM 被抑制时，特殊培养基可以支持核成熟但不支持细胞质成熟。结果表明，CCs 的 GM 通过从戊糖磷酸途径和糖酵解释放代谢物来促进猪卵母细胞成熟。在猪 DOs 中，丙酮酸和乳酸都通过单羧酸转运蛋白转移，在猪 DOs 和 CCs 中，丙酮酸进一步通过线粒体丙酮酸载体进入线粒体。在猪 DOs 和 CCs 中，丙酮酸和乳酸分别通过线粒体电子传递和 LDH 催化氧化为丙酮酸来利用。猪和小鼠 DOs 在葡萄糖、丙酮酸和乳酸利用方面对 CC 的依赖性不同。虽然小鼠 DOs 不能利用，但猪 DOs 可以利用乳酸衍生的丙酮酸。
