表儿茶素对小鼠卵母细胞mtDNA拷贝数和胚胎体外发育能力的影响

本研究旨在探究表儿茶素(epicatechin,EC)对小鼠体外成熟培养卵母细胞线粒体DNA(mtDNA)拷贝数及其随后孤雌激活胚胎发育能力的影响。小鼠卵丘-卵母细胞复合体(COCs)在添加不同浓度EC(0、5、10、15、20μmol/L)的成熟液中体外成熟培养16h后,采用实时荧光定量PCR的方法检测卵母细胞mtDNA拷贝数;同时,通过对卵母细胞进行孤雌激活处理,探讨其后续胚胎的体外发育能力。实时荧光定量PCR分析结果显示,添加EC各处理组的卵母细胞mtDNA拷贝数均有所增加,其中,10、15μmol/L组的mtDNA拷贝数均显著高于0μmol/L对照组(P0.05);但10μmol/L组mtDNA拷贝数更接近自然排卵周期合子的mtDNA含量(P0.05)。体外培养观察结果发现,成熟液中添加10μmol/L EC能提高卵母细胞第一极体排出率,与对照组相比差异不显著(P0.05),但能显著提高卵母细胞孤雌激活后胚胎的囊胚发育率(P0.05)。综上表明,小鼠卵母细胞体外成熟液中添加10μmol/L EC可提高卵母细胞的mtDNA拷贝数,有利于促进卵母细胞后续的发育能力。

Effect of Epicatechin on Mitochondrial DNA (mtDNA) Copy Number and Developmental Competence of Rat Oocytes Following Maturation and Culture in vitro

This study was designed to investigate the effect of epicatechin (EC) on mitochondrial DNA (mtDNA) copy number and developmental competence of rat oocytes following maturation and culture in vitro. Cumulus-oocyte complexes were respectively cultured in the maturation medium supplemented with different concentrations of EC (0, 5, 10, 15 and 20 μmol/L) for 16 h. And then the mtDNA copy number in matured oocytes was detected with the method of Real-time PCR. Moreover, the subsequent developmental competence of embryos from parthenogenetic activation (PA) was examined. The PCR result showed that the mtDNA copy number in each EC treatment group were increased than that of control group, and there was remarkably increase in the both groups of 10 and 15 μmol/L compared with the control group (P<0.05), but the number of 10 μmol/L group was more closed to that of the nature ovulation cycle oocytes (P>0.05). Furthermore, the result of in vitro culture showed that adding with 10 μmol/L EC into the maturation medium, there were no significant effect in the maturation rate of oocytes (P>0.05), but the developmental rate of blastocyst after PA was significantly improved than that of control group (P<0.05). The datas above showed that adding 10 μmol/L EC into the maturation medium could increase the mtDNA copy number of oocytes, and contribute to improve its subsequent developmental competence.