Cellular and Molecular Biology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran.
Biochem Biophys Res Commun. 2019 Feb 26;510(1):110-115. doi: 10.1016/j.bbrc.2019.01.056. Epub 2019 Jan 17.
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.
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.
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.
The IVM oocytes, probably, did not suffice to recover the high level of paternal genomic damage and inhibition of apoptosis pathway beginning.
精子 DNA 完整性和卵母细胞质量显著影响胚胎发育和存活。本研究根据精子 DNA 碎片化（SDF）水平评估了体外成熟 MII 卵母细胞来源的胚胎发育和质量，以及凋亡相关基因和 microRNAs 的表达水平。
从 50 个具有任何可识别的女性因素不孕的 ICSI 周期中收集精液和未成熟卵母细胞。卵巢刺激后，收集生发泡期（GV）卵母细胞并在体外成熟（IVM）培养基中培养 24 小时。然后，测定培养基中活性氧（ROS）水平。使用精子染色质分散（SCD）试验评估处理后的精液 SDF 水平，并将 SDF 水平分为 SDF≤30%和 SDF>30%。在胞质内注射后 72 小时，记录组 I（GV-MII+SDF≤30%）和组 II（GV-MII+SDF>30%）中胚胎的发育和质量评分。此外，通过定量实时 PCR 和 TUNEL 染色分别在分子和细胞水平评估桑葚胚期胚胎的凋亡发生率。
两组的卵裂率无差异。来自 IVM 成熟卵母细胞和高水平 SDF 的胚胎的质量评分明显低于低水平 SDF（P<0.05）。与组 I 相比，组 II 胚胎的 BCL-2 表达显著降低（P<0.05）。此外，它们显示出促凋亡 microRNAs；miR 15a 和 miR 16-1 的相对转录增加（P<0.05）。与组 I 相比，在组 II 中观察到胚胎 TUNEL 阳性卵裂球增加，但未达到显著水平。
IVM 卵母细胞可能不足以恢复高水平的父本基因组损伤和开始抑制凋亡途径。
