Abstract
Low birth efficiency and developmental abnormalities in embryos derived using round spermatid injection (ROSI) limit the clinical application of this method. Further, the underlying molecular mechanisms remain elusive and warrant further in-depth study. In this study, the embryonic day (E) 11.5 mouse fetuses and corresponding placentas derived upon using ROSI, intracytoplasmic sperm injection (ICSI), and natural in vivo fertilized (control) embryos were collected. Transcriptome and DNA methylation profiles were analyzed and compared using RNA-sequencing (RNA-seq) and whole-genome bisulfite sequencing, respectively. RNA-seq results revealed similar gene expression profiles in the ROSI, ICSI, and control fetuses and placentas. Compared with the other two groups, seven differentially expressed genes (DEGs) were identified in ROSI fetuses, and ten DEGs were identified in the corresponding placentas. However, no differences in CpG methylation were observed in fetuses and placentas from the three groups. Imprinting control region methylation and imprinted gene expression were the same between the three fetus and placenta groups. Although 49 repetitive DNA sequences (RS) were abnormally activated in ROSI fetuses, RS DNA methylation did not differ between the three groups. Interestingly, abnormal hypermethylation in promoter regions and low expression of Fggy and Rec8 were correlated with a crown-rump length less than 6 mm in one ROSI fetus. Our study demonstrates that the transcriptome and DNA methylation in ROSI-derived E11.5 mouse fetuses and placentas were comparable with those in the other two groups. However, some abnormally expressed genes in the ROSI fetus and placenta warrant further investigation to elucidate their effect on the development of ROSI-derived embryos.
Highlights
Since the first successful use of in vitro fertilization (IVF) in Britain in 1978 (Steptoe and Edwards, 1978), rapid advances in assisted reproductive technology (ART) have benefited millions of families worldwide (Niederberger et al, 2018; De Geyter, 2019)
The blastocyst percentage was higher in the round spermatid injection (ROSI) group than that in the intracytoplasmic sperm injection (ICSI) group (88.79% vs. 75.19%, P < 0.01) (Supplementary Figure S1B), which may be explained by the smaller diameter of the injection needle used for ROSI (6–7 μm) than for ICSI (9–10 μm)
Nine differentially expressed genes (DEGs) were identified between control and ROSI fetuses and 18 DEGs between the ICSI and ROSI fetuses, and seven DEGs were shared in both comparisons (Figure 1B)
Summary
Since the first successful use of in vitro fertilization (IVF) in Britain in 1978 (Steptoe and Edwards, 1978), rapid advances in assisted reproductive technology (ART) have benefited millions of families worldwide (Niederberger et al, 2018; De Geyter, 2019). Concerns about the health of babies conceived using ART remain (Lazaraviciute et al, 2014; Kawwass and Badell, 2018; Hattori et al, 2019), especially since 1992, when intracytoplasmic sperm injection (ICSI) was first employed to produce offspring (Palermo et al, 1992). After the successful injection of mature sperm into the oocyte to produce offspring in animals and humans (Kimura and Yanagimachi, 1995a), the microinjection of immature germ cells, such as round spermatids, into oocytes has been evaluated (Ogura et al, 2005). Round spermatids are precursors of mature spermatozoa, and the transformation of round spermatids into mature spermatozoa involves the replacement of histones in chromatin with arginine-rich protamine, acrosome formation, and flagellum formation, resulting in the attainment of motility (Yanagimachi, 2005)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
