| [Background] Mitochondria are important organelles in mammals. Mitochondria can produce ATP and supply energy in oocytes maturation and early embryonic development.Therefore,the number and function of mitochondria is essential for early embryonic development.The change of mitochondrial function may be compensated and adjusted by the change of mitochondrial numbers.The change of mitochondrial DNA copy numbers may reflect the function of mitochondria. At present, studies on different animals about mitochondrial DNA copy numbers in oocyte maturation and sperm quality have been reported, but there are few reports about the mitochondrial DNA copy numbers in human early embrys. As a new type of gene sequencing technology,NGS(Next generation sequencing)has been widely used in the fields of genetic testing and in the study of hereditary diseases.NGS can sequence the whole human genome with lower cost.With the development of reproductive technology, the PGD/PGS has played a important part in preimplantation genetic test(PGT).PGD can detect genetic materials of gametes and embryos,PGS mainly screens the embryo chromosome aneuploidy abnormality. The combined use of NGS technology and thePGD/PGS enables embryonic cell biopsy and gene detection with little damage of embryos.[Objective] This study aims to analyze the correlativity between mtDNA copy number and different embryo morphology parameters and clinical factors.So,we can essess the developmental potential of embryosand learn more about the process of embryonic development.[Methods]This study totally selected 279 embryos of 39 couple,who were treated with PGD/PGS in reproductive center of our hospital on March 2014 to September 2015.According to clinical needs,blastomeres or trophoblastic cells were biopsied on 3?5?6?7 days after fertilization. And embryos after biopsy were vitrification frozen.Blastomeres and trophoblastic cells biopsied were performed to genes testing using NGS technology.Then we analysis the relationship exists between various factors and early embryonic mitochondrial DNA copy numbers.[Results] 1.The mitochondrial DNA copy numbers of embryosin Grade I and Grade????? at day 2 after being fertilized were 504.69±85.222 and 34335.25± 16042.469 (p<0.05),which had statistical difference;2. The mitochondrial DNA copy numbers of blastaea in<5% and >5% fragmentation at Days 2 human embryos were 519.94±77.708,43204.84±20135.024, and 519.94±77.708,43204.84±20135.024 at Days 3 human embryos, whith were statistically significant;3.The mitochondrial DNA copy numbers of embryos in ?3 cells,4cell??5cell at day 2 after being fertilized were 24442.91±14952.26,749.62±212.24,48807.06±31535.96 respectively.Each two groups comparison found statistically significant differences between the three groups. The mitochondrial DNA copy numbers of embryos in ?6 cells,7-8cell??9cell at day 3 after being fertilized were 45059.98124203.006,3484.74±2831.457,9382.3118699.437 respectively,the difference was statistically significant; 4. No significant differences were found between mtDNA copy numbers and female age, male age, duration of infertility, controlled ovarian hyperstimulation, basal follicle stimulating hormone(FSH) levels,total dosage of gonadotrophins administration.[Conclusion] There were remarkable correlation between mitochondrial DNA copy number in early embryonic and different embryonic quality,fragmentations.numbers of blastomeres.The high quality of embryos with less fragments and 4-cell embryos of D2, 7-8cell embryos of D3 were suggested to be transplanted for their development potential may be higher. |
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