Laser assisted zona hatching does not lead to immediate impairment in human embryo quality and metabolism

Laser assisted zona hatching (LAH) is a routinely used therapeutic intervention in assisted reproductive technology for patients with poor prognosis. However, results are not conclusive in demonstrating the benefits of zona hatching in improving the pregnancy rate. Recent observations on LAH induced genetic instability in animal embryos prompted us to look into the effects of laser assisted zona hatching on the human preimplantation embryo quality and metabolic uptake using high resolution nuclear magnetic resonance (NMR) technology. This experimental prospective study included fifty embryos from twenty-five patients undergoing intra cytoplasmic sperm injection. Embryo quality assessment followed by profiling of spent media for the non-invasive evaluation of metabolites was performed using NMR spectroscopy 24 hours after laser treatment and compared with that of non-treated sibling embryos. Both cell number and embryo quality on day 3 of development did not vary significantly between the two groups at 24 hours post laser treatment interval. Time lapse monitoring of the embryos for 24 hours did not reveal blastomere fragmentation adjacent to the point of laser treatment. Similarly, principal component analysis of metabolites did not demonstrate any variation across the groups. These results suggest that laser assisted zona hatching does not affect human preimplantation embryo morphology and metabolism at least until 24 hours post laser assisted zona hatching. However, studies are required to elucidate laser induced metabolic and developmental changes at extended time periods. <b>Abbreviations</b>: AH: assisted hatching; ART: assisted reproductive technology; DNA: deoxy-ribo nucleic acid; LAH: laser assisted hatching; MHz: megahertz; NMR: nuclear magnetic resonance; PCA: principal component analysis; PGD: preimplantation genetic diagnosis; TLM: time lapse monitoring

激光辅助透明带开孔（laser assisted zona hatching, LAH）是辅助生殖技术（assisted reproductive technology, ART）中针对预后不良患者的常规治疗手段。然而，其通过透明带开孔提升妊娠率的获益尚未得到确凿证实。近期有研究观察到LAH可诱导动物胚胎出现遗传不稳定现象，这促使我们借助高分辨率核磁共振（nuclear magnetic resonance, NMR）技术，探究激光辅助透明带开孔对人类植入前胚胎质量及代谢摄取的影响。本前瞻性实验研究纳入了25例行卵胞浆内单精子注射患者的50枚胚胎。研究人员在激光处理24小时后，对胚胎质量进行评估，并采用核磁共振波谱法分析废弃培养基的代谢物谱，以无创评估胚胎代谢状态，并将其与未接受激光处理的同胞胚胎进行对比。激光处理后24小时，两组胚胎在发育第3天的细胞数及胚胎质量均无显著差异。对胚胎进行24小时的延时监测（time lapse monitoring, TLM）未发现激光处理位点附近出现卵裂球碎片。同样，代谢物的主成分分析（principal component analysis, PCA）也未显示两组间存在任何差异。上述结果表明，至少在激光辅助透明带开孔后24小时内，该操作不会影响人类植入前胚胎的形态学及代谢状态。不过，仍需开展进一步研究以阐明激光诱导的代谢及发育变化在更长时间周期内的具体表现。缩写说明：AH：辅助透明带开孔（assisted hatching, AH）；ART：辅助生殖技术（assisted reproductive technology, ART）；DNA：脱氧核糖核酸（deoxy-ribo nucleic acid, DNA）；LAH：激光辅助透明带开孔（laser assisted hatching, LAH）；MHz：兆赫（megahertz, MHz）；NMR：核磁共振（nuclear magnetic resonance, NMR）；PCA：主成分分析（principal component analysis, PCA）；PGD：植入前胚胎遗传学诊断（preimplantation genetic diagnosis, PGD）；TLM：胚胎延时监测（time lapse monitoring, TLM）