P-266 Study on the mechanisms of ovol1/2 during the morula-to-blastocyst transition

Abstract Study question Screen the key gene groups that determine development of blastocyst. Explore effect ovol1/2 on early embryonic development. Summary answer We founded there were insufficient activation Major ZGA genes in AE group,and focused candidate ovol1/2. What is known already At present, clinical success rate assisted reproductive technology (ART) less than 50%. A large number embryos cultured vitro can not develop to blastocyst, and are cleavage or morula stage arrest. The developmental arrest preimplantation an important reason for treatment failure infertile patients. However, cause clear, also a lack effective methods improve embryo quality. design, size, duration In this study, fertilized obtained through ICSI single cell from eight-cell was biopsied micromanipulation single-cell RNA sequencing (scRNA-seq). Subsequently, we tracked potential remaining cells divided them into high-quality blastocyst(Bla) group failed blastocyst formation(arrest embryo, AE) group. addition,we employed RNAi approach study function ovol1/2, by injecting ovol1/2-targeting small interfering RNAs (siovol1/2) wild-type (WT) zygotes. Participants/materials, setting, collected 21 human blastocysts 5 embryos. Human immature oocytes treatments clinically discarded donated women after signing informed consent donors. C57B6 background mouse strains used study. Mice maintained under specific pathogen free conditions controlled environment 20–22 °C,with 12/12 h light/dark cycle, 50–70% humidity, food water provided. Main results role chance showed expression significantly different Bla group: 79.5% differential down-regulated, including 48.3% gene. Then When knocked down alone, no significant difference 2-cell between knockdown normal control at same time, among three before stage. But developed stage, differences embryos: about 73% formed blastocyst; 39% low-dose group; high-dose all arrested Further investigation revealed inner mass(ICM) did change significantly, while trophoblastic ectoderm(TE) decreased. addition, TE functions such as cavity paved area, hatching adhesion damaged. Limitations, reasons caution research mechanisms needed. Wider implications findings This understand molecular development, will provide theoretical basis diagnosis intervention Our provides clues causes abnormal formation new ideas possible improvements ART. Trial registration applicable