Effect of sperm entry on blastocyst development after in vitro fertilization and intracytoplasmic sperm injection — mouse model

Abstract

Purpose To investigate whether in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI), influence the embryo's development and its quality using the mouse as a model. Methods Assisted fertilization was performed using ICSI and IVF. Fluorescent beads were adhered to the fertilization cone or place of previous sperm injection in the natural mated (NM), IVF and ICSI embryos, respectively. Embryo examination was carried out at the two-cell and blastocyst stage to determine the position of fluorescent bead. Protein expression was detected by fluorescence immunocytochemical staining and confocal microscopic imaging of blastocysts. Results IVF and ICSI embryos developed at rates comparable to NM group. Embryos show similar expression patterns of two transcription factors, Oct4 and Cdx2. The most preferred place for spermatozoa attachment was the equatorial site of the egg, whether fertilization occurred in vitro or under natural conditions. We also link the sperm entry position (SEP) to embryo morphology and the number of cells at the blastocyst stage, with no influence of the method of fertilization. Conclusions IVF and ICSI, do not compromise in vitro preimplantation development. Additional data, related to sperm entry, could offer further criteria to predict embryos that will implant successfully. Based on embryo morphology, developmental rate and protein expression level of key transcription factors, our results support the view that ART techniques, such as IVF and ICSI, do not perturb embryonic development or quality.

Influence of radiofrequency–electromagnetic waves from 3rd‐generation cellular phones on fertilization and embryo development in mice

“…The rates of fertility, 8‐cell embryo formation, and blastocyst formation with IVF in each group were higher than 90%, and no significant differences were found across the exposure conditions. The overall rates of fertility and embryogenesis in our study were about the same as those reported in prior non‐exposed studies [Siddiquey and Cohen, ; Depypere et al, ; Sztein et al, ; Tateno and Kamiguchi, ; Ma et al, ; Piotrowska‐Nitsche and Chan, ], indicating that the basic condition of fertilization and embryogenesis in our study is comparable to previous studies.…”

Reconstruction of mammalian oocytes by germinal vesicle transfer: A systematic review

“…ICSI: ICSI was done in HEPES-CZB within 1-2 hr after NT (4,11,12,42). Immobilized spermatozoa were injected inside the ooplasm in HEPES-medium (KSOM) containing 20% FBS (4,7,8,11,12,(29)(30)(31)42).…”

“…ICSI: ICSI was done in HEPES-CZB within 1-2 hr after NT (4,11,12,42). Immobilized spermatozoa were injected inside the ooplasm in HEPES-medium (KSOM) containing 20% FBS (4,7,8,11,12,(29)(30)(31)42). In this way, a small droplet of sperm suspension incubated for 1 hr at 37 o C was mixed thoroughly with an equal volume of HEPES-CZB medium with 12% (w/v) PVP immediately before ICSI (7,8,11,12,(29)(30)(31).…”

Deposition of the spermatozoon in the human oocyte at ICSI: impact on oocyte survival, fertilization and blastocyst formation

“…Ajduk and colleagues further characterized the relative contribution made by either the sperm per se or the fertilization cone (FC), i.e., a transient protrusion at the site of sperm entry [11] occurring in respectively about 69 and 76 % of mouse zygotes after natural conception or in vitro fertilizaton (IVF) [21]. While the FC is not observed after standard intracytoplasmic sperm injection (ICSI) by depositing the spermatozoon arbitrarily in the mouse oocyte, it does appear when the spermatozoon is deposited under the oocyte cortex [3].…”