Background: Sperm DNA integrity and oocyte quality significantly affect embryo development and survival. The current study evaluated embryo development and quality, as well as the expression level of apoptosis-related genes and microRNAs in embryo derived from in vitro matured MII oocytes according to sperm DNA fragmentation (SDF) level.
Methods: The semen and immature oocytes were collected from 50 ICSI cycles with any recognizable female factor infertility. After ovarian stimulation, germinal vesicle stage (GV) oocytes were collected and incubated in in vitro maturation (IVM) medium for 24 h. Next, reactive oxygen species (ROS) level of media culture was determined. Using by sperm chromatin dispersion (SCD) test, the SDF levels of processed semen were assessed and categorized into SDF ≤ 30% and SDF>30%. Seventy two hours after intracytoplasmic injection, the embryo development and quality score were recorded in the groups I (GV-MII + SDF≤ 30%) and II (GV-MII + SDF> 30%). Also, the apoptosis incidence of embryos at morula stage was evaluated at molecular and cellular levels by quantitative real time PCR and TUNEL staining, respectively.
Results: Cleavage rate did not differ between two groups. The quality score of embryos obtained from IVM matured oocytes and high level of SDF was significantly lower than that of low level of SDF (P < 0.05). The embryos from group II had a significant reduction of the expression of BCL-2 compared to group I (P < 0.05). Also, they showed an increase in relative transcription of pro-apoptotic microRNAs; miR 15a and miR 16-1 versus group I (P < 0.05). A rise of TUNEL positive blastomers of embryo was observed at group II versus group I, but it did not reach to significantly level.
Conclusion: The IVM oocytes, probably, did not suffice to recover the high level of paternal genomic damage and inhibition of apoptosis pathway beginning.
Keywords: Apoptosis; Embryo development; In vitro maturation; Oocyte; Sperm DNA fragmentation.
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