Abstract
Implantation failure and early pregnancy loss have been reported to be closely related to the quality of mammalian oocytes; however, the pregnant outcome of embryos from in-vitro matured (IVM) oocytes remains unknown. In this study we examined spindle assembly and chromosome segregation during differentiation, and the duration of IVM of mouse oocytes. The resulting implantation and pregnancy outcomes were analyzed to clarify the relationship between the spindle and chromosomes of IVM oocytes and implantation and early pregnancy. Cumulus-enclosed germinal vesicle oocytes were collected and randomly cultured in IVM medium with different IVM durations. One part of IVM oocytes were analyzed the spindle and chromosome morphology by immunofluorescence method, and the other part of them were fertilized by intracytoplasmic sperm injection. The resulting embryos were transferred into pseudo-pregnant female mice, and the post-implantation and full term development was observed. The chromosome aberrations and incorrect spindle assembly seems not affect the early development and blastocyst cell number derived from IVM oocytes, however the development potential of the resulting embryos after implantation were significant decreased with the ratio increasing of chromosome aberrations and incorrect spindle assembly. Accordingly, the full-term development was also decreased. In conclusion, the present study showed the spindle assembly of in vitro-matured oocytes was one of the most important factors that affected the implantation and ongoing pregnancy rates of IVM oocytes, and the improvement by an appropriate duration of maturation in vitro will enhance the post-implantation development potential of the resulting embryos, and decrease implantation failure and early pregnancy loss.
Highlights
Assisted reproductive techniques (ART) have resulted in tremendous benefits to infertile couples since Louise Brown, the first tube baby, was born in 1978 [1]
Some studies have indicated that the higher pregnancy loss rate appears to be related to the underlying etiology for infertility (e.g., polycystic ovarian syndrome (PCOS)) rather than the in vitro maturation (IVM) procedure [6]; Suikkari et al reviewed the pregnancy results of IVM cycles by some centers and suggested that at present, the most important reason for the infrequent use of IVM in most clinics is the lower pregnancy rate compared with conventional in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) [7]
A study involving the composition of matured medium has shown that small molecular chemicals, such as cAMP [15], serum [16], growth factors [17], and PDE3 inhibitor [18], will improve cytoplasmic maturation; we recently found the developmental potential of IVM oocytes after parthenogenetic activation could be significantly improved by adjusting the maturation time [19]
Summary
Assisted reproductive techniques (ART) have resulted in tremendous benefits to infertile couples since Louise Brown, the first tube baby, was born in 1978 [1]. Some studies have indicated that the higher pregnancy loss rate appears to be related to the underlying etiology for infertility (e.g., PCOS) rather than the IVM procedure [6]; Suikkari et al reviewed the pregnancy results of IVM cycles by some centers and suggested that at present, the most important reason for the infrequent use of IVM in most clinics is the lower pregnancy rate compared with conventional IVF/ICSI [7]. One group reported higher implantation rates, but higher pregnancy loss rates after IVM [8] To compensate for this poor embryo quality, some groups have transferred $3 embryos in IVM cycles to achieve acceptable pregnancy outcomes [9,10]
Sign-in/Register to view highlights & summary 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.
