线粒体DNA拷贝数对卵母细胞受精结局的影响

摘要

Objective:To determine the effect of mitochondrial DNA (mtDNA) copy number on fertilization outcome of oocytes in order to provide new idea for improving fertilizing rate.Methods:The mtDNA copy number in fertilized and unfertilized oocytes and embryos were analyzed by real-time polymerase chain reaction (PCR).Results:There were 52 unfertilized oocytes in group A, 46 fertilized oocytes with pronucleus blocking in group B and 61 mono-pronucleus(lPN)or tri-pronucleus(3PN)embryoes in group C. The mtDNA copy number in group A (80, 547 + 37, 314 copies/μl) was significantly fewer than that in group B (104,311 + 43,074) copies/μl and group C (192,681 ±51,394) copies/μl(P<0. 01). The mtDNA copy number in group B was significantly fewer than that in group C(P<0. 05). Group C was divided to two subgroup:group Cl (poor quality of embryos and debris more than 5%) and group C2 (normal development of embryos). The mtDNA copy number in group Cl [(146, 836 + 36, 585) copies/μl] was significantly fewer than that in group C2[(297,268 + 102,369) copies/μl](P = 0. 000).Conclusions; Mitochondrial DNA copy number is critical for fertilization outcome and can be as an important marker of oocyte quality. It may explain some cases of fertilization failure.%目的 研究线粒体DNA拷贝数对卵母细胞受精结局的影响,为提高卵子质量,改善体外受精结局提供新思路.方法 应用实时荧光定量聚合酶链反应技术检测不同受精结局的卵母细胞线粒体DNA(mtDNA)拷贝数,并对各组结果作比较分析. 结果 A组52枚未受精卵的平均mtDNA拷贝数为(80,547±37,314) copies/μl,B组46枚发生原核阻滞的正常受精合子平均mtDNA拷贝数为(104,311±43,074) copies/μl,C组61枚单原核(1PN)或三原核(3PN)胚胎平均mtDNA拷贝数为(192,681±51,394) copies/μl.拷贝数A组显著小于B、C两组(P＜0.01),B组显著小于C组(P＜0.05).C组中碎片率＞30％的较差胚胎(C1组)和碎片率＜5％、发育速度正常的良好胚胎(C2组)两个亚组,两组的平均mtDNA拷贝数分别为(146,836±36,585)copies/μl和(297,268±102,369) copies/μl,两组比较结果有显著性差异(P=0.000). 结论 线粒体DNA拷贝数可作为衡量卵母细胞和胚胎质量的重要指标,线粒体缺乏可能是部分体外受精失败的原因.