RESUMO
Objective: vitrification is increasingly used in assisted reproductive technology [ART] laboratories worldwide. In this study the effect of vitrification on the expression and modifications of H3 histones of Igf2 and Oct4 was investigated in blastocysts cultured from vitrified and non-vitrified two-cell embryos
Materials and Methods: in this experimental study, two-cell embryos were cultured in KSOM medium to reach the blastocyst stage. Expression of Igf2 and Oct4 and modifications of H3 histones in regulatory regions of both genes were compared with in vivo blastocysts, which comprise the control group. To gene expression evaluation, reverse transcription-quantitative polymerase chain reaction [RT-qPCR] and the ChIP assay method were carried out to assess expression and histone modifications of the two genes
Results: the expression level of Igf2 was significantly higher in both experimental groups than the control group. In the regulatory region of Igf2, H3K9 methylation decreased whereas H3K9 acetylation increased in the experimental group compared with the control group. In contrast, the expression level of Oct4 was significantly lower in experimental groups. The Oct4 gene promoter showed a significant increase in H3K9 methylation and decrease in H3K9 acetylation [P<0.05]
Conclusion: according to our results, both vitrification and cultivation conditions may lead to changes in expression level and modification of histones in Igf2 and Oct4. However, these effects were the same in vitrified and non-vitrified groups. Indeed, the embryo is most affected by culture environment and in vitro culture. Therefore, vitrification may be used as a low-risk technique for embryo cryopreservation in ART
RESUMO
The aim of this study is to investigate the effect of ISM1 culture medium on embryo development, quality and outcomes of in vitro fertilization/intracytoplasmic sperm injection [IVF/ICSI] cycles. This study compares culture medium commonly used in the laboratory setting for oocyte recovery and embryo development with a medium from MediCult. We have assessed the effects of these media on embryo development and newborn characteristics. In this prospective randomized study, fertilized oocytes from patients were randomly assigned to culture in ISM1 [MediCult, cycles: n=293] or routine lab culture medium [G-1[TM]v5; Vitrolife, cycles: n=290] according to the daily media schedule for oocyte retrieval. IVF or ICSI and embryo transfer were performed with either MediCult media or routine lab media. Embryo quality on days 2/3, cleavage, pregnancy and implantation rates, baby take home rate [BTHR], in addition to the weight and length of newborns were compared between groups. There were similar cleavage rates for ISM1 [86%] vs. G-1[TM] v5 [88%]. We observed a significantly higher percentage of excellent embryos in ISM1 [42.7%] compared to G-1[TM] v5 [39%, p<0.05]. Babies born after culture in ISM1 had both higher birth weight [3.03 kg] and length [48.8 cm] compared to G-1[TM] v5 babies that had a birth weight of 2.66 kg and a length of 46.0 cm [p<0.001 for both]. This study suggests that ISM1 is a more effective culture medium in generating higher quality embryos, which may be reflected in the characteristics of babies at birth
RESUMO
The appropriate interaction between a blastocyst and the endometrium is essential for successful implantation. Numerous factors, including hormone receptors [progesterone receptor], cytokines [leukemia inhibitory factors [LIF]], and adherence molecules such as E-cadherin are involved in the cross-talk that occurs between the embryo and endometrium. Studies show that a lack of these genes impact endometrial receptivity. In this study, we compare the expression levels of E-cadherin, LIF, and progesterone receptor [PgR] genes in blastocysts that have been obtained from superovulated mice to those obtained from natural cycles. In this experimental study, for the experimental group, a total of 17 virgin female NMRI mice [6- 8 weeks old] were injected with 7.5 IU pregnant mare serum gonadotropin [PMSG]. Their blastocysts [approximately n= 120] were flushed out after 3.5 days, following administration of human chorionic gonadotropin [hCG]. The control group consisted of blastocysts from 62 female mice that were mated with male mice. The natural cycle blastocysts were flushed out from the female mice uteri 3.5 days after mating. The expression levels of E-cadherin, LIF, t PgR genes were examined by quantitative real-time reverse-transcriptase polymerase chain reaction [RT-PCR]. Data were analyzed by the student's t-test [one sample t-test]. Expression levels of all studied genes were significantly lower in the hormone-treated group compared to the natural cycle blastocysts [p<0.05]. Although ovarian stimulation is utilized to obtain more oocytes in ART cycles, it seems that this could disadvantageous to implantation because of the decrease in expression levels of certain genes. Because of the important roles of E-cadherin, LIF, and progesterone receptor in the implantation process, we have shown lower expression levels of these genes in mouse blastocysts obtained from ovarian-stimulated mice than those derived from the natural cycle. The results observed in this study have shown the possibility of an unfavorable effect on implantation and pregnancy rate