线粒体能量代谢和DNA复制对小鼠卵子体外成熟、受精及发育的影响

目的 探讨胞质线粒体的氧化磷酸化（OXPHOS）活性或线粒体DNA复制在卵子成熟、受精和胚胎发育过程中的作用。方法 通过在小鼠体外成熟培养液中引入不同浓度的羰基氰4-(三氟甲氧基)苯腙 (FCCP, 10 nmol/L和100nmol/L)或2′,3′-双脱氧胞苷(ddC,10μmol/L和100μmol/L)，抑制线粒体OXPHOS活性或线粒体DNA复制，统计分析各组卵子的体外生发泡破裂（GVBD）率、核成熟率、受精率及囊胚形成率，以分析线粒体功能抑制对卵子成熟、受精和胚胎发育的影响。 结果 线粒体OXPHOS活性和DNA复制功能在卵子和胚胎中所发挥的作用并不完全相同。FCCP抑制线粒体OXPHOS活性可显著降低卵子的核成熟率和囊胚形成率；但对卵子的GVBD的发生率和受精率无显著影响。而ddC抑制线粒体DNA复制不影响卵子的体外成熟和受精，但可显著抑制囊胚的形成。 结论 OXPHOS活性主要影响卵子成熟及胚胎发育；线粒体DNA复制则主要影响胚胎发育；而线粒体功能抑制不影响卵子的成熟启动和体外受精。

Effects of mitochondrial metabolic activity and mitochondrial DNA replication on maturation, fertilization and developmental competence in vitro of rat oocytes

Objective To investigate the roles of mitochondrion on whether either mitochondrial DNA copy number or its metabolic capacity is an essential factor for both oocyte maturation and embryo development. Methods Both the metabolic inhibitor (FCCP) and the inhibitor of mitochondrial DNA replication(ddC) were introduced into the culture medium in order to analyze the affection of mitochondria rates of germinal vesicle breakdown. Nuclear maturation, fertilization and blastulation were assessedin vitro. Results The inhibiting mitochondrial DNA replication did not coincide with the mitochondrial metabolic capacity in oocytes. FCCP treatment significantly reduced the rate of nuclear maturation of oocytes and the development potential of embryos compared to untreated controls. Treatment of ddC did not affect maturationin vitro of oocytes, but impaired blastulation. Neither FCCP nor ddC treatment had an effect on the rate of fertilization. Conclusion Inhibiting mitochondrial metabolic activity during oocyte maturation has a negative impact on oocyte maturation and ensuing embryo developmental competence. Reduction in mitochondrial DNA copy number mainly affects embryonic development potential, but has little effect on oocyte maturation and fertilizationin vitro.