Peer Review #1 of "Comparing transcriptome profiles of human embryo cultured in closed and standard incubators (v0.1)"

Abstract

It is necessary to compare the transcriptomic profiles of human embryos cultured in timelapse imaging incubators (TLI) and standard incubators (SI) in order to determine whether a closed culture system has a positive impact on embryos. In this study, we used RNAsequencing (RNA-Seq) to characterize and compare the gene expression profiles of eightcell embryos of the same quality grade cultured in TLI and SI. We sequenced a total of 580,952,620 reads for zygotes, TLI-cultured, and SI-cultured eight-cell embryos. The global transcriptomic profiles of the TLI embryos were similar to those of the SI embryos and were highly distinct from the zygotes. We also detected 539 genes showing differential expression between the TLI and SI groups with a false discovery rate (FDR) < 0.05. Using gene ontology (GO) enrichment analysis, we found that the highly expressed SI genes tended to execute functions such as transcription, RNA splicing, and DNA repair, and that the highly expressed TLI genes were enriched in the cell differentiation and methyltransferase activity pathways. This study, the first to use transcriptome analysis to compare SI and TLI, will serve as a basis for assessing the safety of TLI application in assisted reproductive technology (ART).