Sequential analysis of global gene expression profiles in immature and in vitro matured bovine oocytes: potential molecular markers of oocyte maturation

Abstract Background Without intensive selection, the majority of bovine oocytes submitted to in vitro embryo production (IVP) fail to develop to the blastocyst stage. This is attributed partly to their maturation status and competences. Using the Affymetrix GeneChip Bovine Genome Array, global mRNA expression analysis of immature (GV) and in vitro matured (IVM) bovine oocytes was carried out to characterize the transcriptome of bovine oocytes and then use a variety of approaches to determine whether the observed transcriptional changes during IVM was real or an artifact of the techniques used during analysis. Results 8489 transcripts were detected across the two oocyte groups, of which ~25.0% (2117 transcripts) were differentially expressed (p < 0.001); corresponding to 589 over-expressed and 1528 under-expressed transcripts in the IVM oocytes compared to their immature counterparts. Over expression of transcripts by IVM oocytes is particularly interesting, therefore, a variety of approaches were employed to determine whether the observed transcriptional changes during IVM were real or an artifact of the techniques used during analysis, including the analysis of transcript abundance in oocytes in vitro matured in the presence of α-amanitin. Subsets of the differentially expressed genes were also validated by quantitative real-time PCR (qPCR) and the gene expression data was classified according to gene ontology and pathway enrichment. Numerous cell cycle linked (CDC2, CDK5, CDK8, HSPA2, MAPK14, TXNL4B), molecular transport (STX5, STX17, SEC22A, SEC22B), and differentiation (NACA) related genes were found to be among the several over-expressed transcripts in GV oocytes compared to the matured counterparts, while ANXA1, PLAU, STC1and LUM were among the over-expressed genes after oocyte maturation. Conclusion Using sequential experiments, we have shown and confirmed transcriptional changes during oocyte maturation. This dataset provides a unique reference resource for studies concerned with the molecular mechanisms controlling oocyte meiotic maturation in cattle, addresses the existing conflicting issue of transcription during meiotic maturation and contributes to the global goal of improving assisted reproductive technology

Reproductive decisions of men with microdeletions of the Y chromosome: the role of genetic counselling.

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Tien jaar resultaten van in-vitrofertilisatie in Nederland, 1996-2005

OBJECTIVE: To present the numbers and results of Dutch IVF treatment from 1996-2005 and to describe trends and differences between centres. DESIGN: Retrospective data-collection, description and analysis. METHOD: The annual statistics from all Dutch IVF centres covering the years 1996-2005 were collected, described and analysed. RESULTS: During this period 138,217 IVF or intracytoplasmic sperm injection (ICSI) cycles were started and 14,881 transfers of frozen-thawed embryos (cryo transfers) were performed. The number of ICSI treatments, in particular, increased to more than 6000 cycles during this period. These treatments resulted in 30,488 ongoing pregnancies (22.1% per cycle started; 19.1% for IVF and 23.4% for ICSI). The ongoing pregnancy rate per cycle increased from 17.6% in 1996 to 24.4% in 2005. The increase after cryo transfers was remarkable (from 9.4% to 17.6%). It is estimated that during this period, about 1 in 52 newborns in the Netherlands was an IVF or ICSI child (1996: 1 in 77, 2005: 1 in 43). There were differences between the individual centres regarding the ongoing pregnancy rate per cycle (range: 15.0-26.4%), the percentage of ICSI (range 20-58%), the percentage of cryo transfers per cycle (range: 4-22%) and the multiple pregnancy rate (range 5-27% in 2005). CONCLUSIONS: In the Netherlands the pregnancy rate has increased over the last 10 years as has the number of IVF treatments. Cryo transfers have become increasingly important and the multiple pregnancy rate has decreased. Although thanks to the collaboration of all centres, the current registry produces important data and works well, there are a number of limitations e.g. the retrospective nature with no validation, which must be tackled over the coming year

Efficient reproduction of cynomolgus monkey using pronuclear embryo transfer technique

One of the technical bottlenecks in producing nonhuman primate models is that current assisted reproductive techniques, such as in vitro culture and frozen conservation of multicell-stage embryos, often result in poor embryo quality and subsequently lead to low birth rates. We investigated whether pronuclear embryo transfer can be used as an effective means for improving pregnancy and live birth rates of nonhuman primates. We collected 174 metaphase II oocytes by laparoscopy from 22 superovulated mature females and then fertilized these eggs using either in vitro fertilization or intracytoplasmic sperm injection, resulting in a 33.3% and a 50% fertilization rate, respectively. These 66 fertilized pronuclear-stage embryos were then tubally transferred to 30 recipients and led to 7 births and 1 abortion. Importantly, we observed that the highest live birth rate of ≈64% was obtained when the transfer of pronuclear embryos was performed in the presence of new corpus luteum in the ovary of recipients between 24 h and 36 h after estradiol peak. Therefore, our experiments demonstrate that by matching the critical time window in the recipient's reproductive cycle for achieving optimal embryo-uterine synchrony, pronuclear embryo transfer technology can significantly improve the pregnancy rate and live birth of healthy baby monkeys. This efficient method should be valuable to the systematic efforts in construction of various transgenic primate disease models