METHODS: Given the strict ethical constraints on clinical samples, we employed mouse models in this study. Three experimental groups were established: the naturally conceived (NC) group, the fresh embryo transfer (Fresh-ET) group, and the FET group. Blastocyst formation rates and implantation rates were calculated post-embryo cryopreservation. The impact of FET on fetal growth was evaluated upon fetal and placental weight. Placental RNA-seq was conducted, encompassing comprehensive analyses of various comparisons (Fresh-ET vs. NC, FET vs. NC, and FET vs. Fresh-ET).
RESULTS: Reduced rates of blastocyst formation and implantation were observed post-embryo cryopreservation. Fresh-ET resulted in a significant decrease in fetal weight compared to NC group, whereas FET reversed this decline. RNA-seq analysis indicated that the majority of the expression changes in FET were inherited from Fresh-ET, and alterations solely attributed to embryo cryopreservation were moderate. Unexpectedly, certain genes that showed alterations in Fresh-ET tended to be restored in FET. Further analysis suggested that this regression may underlie the improvement of fetal growth restriction in FET. The expression of imprinted genes was disrupted in both FET and Fresh-ET groups.
CONCLUSIONS: Based on our experimental data on mouse models, the impact of embryo cryopreservation is less pronounced than other in vitro manipulations in Fresh-ET. However, the impairment of the embryonic developmental potential and the gene alterations in placenta still suggested it to be a risky operation.
方法:鉴于临床样本受到严格的伦理约束,我们在这项研究中采用了小鼠模型.建立了三个实验组:自然受孕(NC)组,新鲜胚胎移植(Fresh-ET)组,和FET组。在胚胎冷冻保存后计算囊胚形成率和着床率。根据胎儿和胎盘重量评估FET对胎儿生长的影响。进行胎盘RNA-seq,包括各种比较的综合分析(Fresh-ET与NC,FETvs.NC,和FETvs.新鲜ET)。
结果:胚胎冷冻保存后观察到胚泡形成和着床率降低。与NC组相比,Fresh-ET导致胎儿体重显着下降,而FET扭转了这种下降。RNA-seq分析表明,FET中的大多数表达变化是遗传自Fresh-ET,仅归因于胚胎冷冻保存的改变是中等的。出乎意料的是,某些显示Fresh-ET改变的基因倾向于在FET中恢复。进一步的分析表明,这种消退可能是FET中胎儿生长受限改善的基础。在FET和Fresh-ET组中印迹基因的表达均被破坏。
结论:根据我们对小鼠模型的实验数据,胚胎冷冻保存的影响不如新鲜ET中的其他体外操作明显。然而,胚胎发育潜能的损害和胎盘中的基因改变仍然表明这是一个有风险的手术。