Regulation of oocyte mitochondrial DNA copy number by follicular fluid, EGF, and neuregulin 1 during in vitro maturation affects embryo development in pigs.
Regulation of oocyte mitochondrial DNA copy number by follicular fluid, EGF, and neuregulin 1 during in vitro maturation affects embryo development in pigs.
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DOI：
10.1016/j.theriogenology.2012.04.002
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发表时间：
2012-09-01
期刊：
影响因子：
2.8
通讯作者：
Prather RS
中科院分区：
文献类型：
--
作者：
Mao J;Whitworth KM;Spate LD;Walters EM;Zhao J;Prather RS
关于线粒体DNA在卵母细胞成熟过程中的复制以及细胞外因子对其的调节作用，人们知之甚少。本研究在实验一中确定了在成熟液中添加0、10、20和30%的苏氏卵泡液对mtDNA拷贝数和卵母细胞成熟的影响；实验二研究了EGF(10 ng/m L)、NRG1(20 ng/m L)和NRG1+IGF1(胰岛素样生长因子1,100 ng/m l+NRG-1 20 ng/m L)对mtDNA拷贝数、卵母细胞成熟和孤雌激活后胚胎发育的影响，以及实验3对体外受精后胚胎发育的影响。GV：185,004.7±20,089.3vsMII：239,392.8±10,345.3，P<；0.05)。添加PFF的IVM培养液抑制mtDNA复制(266,789.9±11,790.4 vs 318,510.1±20,377.4，P<；0.05)和卵母细胞减数分裂成熟(67.3±0.7%vs 73.2±1.2，P<；0.01)。与对照组相比，添加生长因子可促进卵母细胞成熟。此外，补充NRG1刺激线粒体复制，导致mtDNA在MII卵母细胞中的拷贝数高于GV卵母细胞，并提高了孤雌胚胎和体外受精胚胎的囊胚率。本研究证实卵母细胞在体外成熟过程中线粒体的生物发生受到刺激。卵母细胞线粒体DNA拷贝数与其发育能力有关。在成熟液中添加NRG1可增加mtDNA拷贝数，从而为提高猪卵母细胞质量和发育能力提供了一种手段。
Little is known about mtDNA replication during oocyte maturation and its regulation by extracellular factors. The present study determined the effects of supplementation of maturation medium with sus scrofa follicular fluid (pFF, 0, 10, 20, and 30%) on mtDNA copy number and oocyte maturation in Experiment 1; the effects on EGF (10 ng/mL), neuregulin 1 (NRG1, 20 ng/mL) and NRG1+IGF1(insulin-like growth factor 1, 100 ng/mL + NRG1 20 ng/mL), on mtDNA copy number, oocyte maturation, and embryo development after parthenogenic activation in Experiment 2, and effects on embryo development after in vitro fertilization in Experiment 3. Overall, mtDNA copy number increased from GV to MII stage oocytes after in vitro maturation (GV: 167,634.6 ± 20,740.4 vs MII: 275,131.9 ± 9,758.4 in Experiment 1, P<0.05; GV: 185,004.7 ± 20,089.3 vs MII: 239,392.8 ± 10,345.3 in Experiment 2, P<0.05). Supplementation of IVM medium with pFF inhibited mtDNA replication (266,789.9 ± 11,790.4 vs 318,510.1 ± 20,377.4, P<0.05) and oocyte meiotic maturation (67.3 ± 0.7% vs 73.2 ± 1.2, for the pFF supplemented and zero pFF control, respectively, P<0.01). Compared to the control, addition of growth factors enhanced oocyte maturation. Furthermore, supplementation of NRG1 stimulated mitochondrial replication, resulted in more mtDNA copies in MII oocytes than GV oocytes, and increased percentage of blastocysts in both parthenogenetic and in vitro fertilized embryos. This study demonstrated that mitochondrial biogenesis in oocytes is stimulated during in vitro maturation. Oocyte mtDNA copy number was associated with its developmental competence. Supplementation of maturation medium with NRG1 increased mtDNA copy number, and thus provides a means to improve oocyte quality and developmental competence in pigs.