Effects of sperm insemination on the final meiotic maturation of mouse oocytes arrested at metaphase I after in vitro maturation / 대한생식의학회지

OBJECTIVE: The aims of this study were to investigate whether fertilization could induce the resumption of meiosis in mouse oocytes arrested at metaphase I (MI) after in vitro maturation (IVM), and to investigate the effect of Ca²⁺ chelator treatment at the time of fertilization on the transition from MI to metaphase II (MII). METHODS: MII-stage and arrested MI-stage mouse oocytes after IVM were fertilized, and then embryonic development was monitored. Blastocysts from each group were transferred into 2.5 days post-coitum pseudo-pregnant ICR mice. MI oocytes after IVM were treated with a Ca²⁺ chelator to investigate the effect of Ca²⁺ oscillations on their maturation. RESULTS: As insemination time increased, the number of oocytes in the MI group that reached the MII stage also increased. The blastocyst rates and total cell numbers in the MII group were significantly higher than in the MI group. No pregnancy occurred in the MI group, but 10 pregnancies were achieved (10 of 12) in the MII group. The proportion of MI oocytes that matured to MII oocytes after fertilization was significantly higher in the non-treated group than in the Ca²⁺ chelator-treated group. CONCLUSION: The findings that a higher proportion of MI-arrested oocytes progressed to MII after fertilization and that the MI-to-MII transition was blocked by Ca2+ chelator treatments before fertilization indicate that the maturation of MI oocytes to MII oocytes is associated with intracellular Ca²⁺ oscillations driven by fertilization.

Application of two different synthetic sequential media for the human IVF-ET program: a prospective, randomized, and comparative study / 대한생식의학회지

OBJECTIVE: Since IVF program was first established, various types of media and culture systems have been developed either in-house or commercially. The aim of this study was to compare the efficacy of in-house Maria Research Center (MRC) media to that of commercially available Sydney IVF media in human day 3 embryo transfer cycles. METHODS: Three hundred sixty nine couples were included in this prospective, randomized, and comparative study. All couples undergoing IVF treatment at the Maria Fertility Hospital were randomly assigned to either Sydney IVF (n=178) or MRC (n=191) media. RESULTS: No difference was observed between the MRC media and Sydney IVF media groups with respect to fertilization rate (74.4% vs. 75.5%). The clinical pregnancy and implantation rates of MRC media (47.1% and 20.0%, respectively) were also similar to those of Sydney IVF media (44.4% and 19.4%, respectively). However, the proportion of embryos with good quality on day 3 was significantly higher in the MRC media group than the Sydney IVF media group (50.2% vs. 43.2%) (p<0.05). CONCLUSION: MRC media were as effective as Sydney IVF media for sustaining embryo development and pregnancy rates. The present study implies that MRC media can be a suitable alternative to commercially available media for human IVF-ET program.