Protein content of porcine embryos during the first nine days of development

The role of nutrients, peptide growth factors and co-culture cells in development of preimplantation embryos in vitro

Our knowledge of the control of preimplantation embryo development and growth is deficient in many aspects as is evidenced by the great difficulty there is in growing embryos of many species in vitro while maintaining viability. This review discusses recent findings on the roles of nutrients, peptide growth factors and co-culture cells in embryo growth and development in vitro.

Proteomic analysis of parthenogenetic and in vitro fertilized porcine embryos

Proteomic data from embryos are essential for the completion of whole proteome catalog due to embryo-specific expression of certain proteins. In this study, using reverse phase LC-MS/MS combined with 1-D SDS-PAGE, we identified 1625 mammalian and 735 Sus scrofa proteins from porcine zygotes that included both cytosolic and membranous proteins. We also found that the global protein profiles of parthenogenetically activated (PA) and in vitro fertilized (IVF) zygotes were similar but differences in expression of individual proteins were also evident. These differences were not due to culture conditions, polyspermy or non-activation of oocytes, as the same culture method was used in both groups, the frequency of polyspermy was 24.3+/-3.0% and the rates of oocyte activation did not differ (p>0.05) between PA and IVF embryos. Consistent with proteomic data, fluorescent Hoechst 33 342 staining and terminal deoxynucleotidyl transferase dUTP nick end labeling assay also revealed that PA embryos were of poor quality as they contained less cells per blastocyst and were more predisposed to apoptosis (p<0.05), although their in vitro development rates were similar. To our knowledge, this is the first report on global peptide sequencing and quantification of protein in PA and IVF embryos by LC-MS/MS that may be useful as a reference map for future studies.

Effects of Developmental Stage, Embryonic Interferon-tau Secretion and Recipient Synchrony on Pregnancy Rate after Transfer of in vitro Produced Bovine Blastocysts

Three separate trials of bovine embryo transfers were performed consisting of 32, 41 and 33 transfers, respectively, to examine the effects of (a) the developmental stage of in vitro-derived blastocysts, (b) the amount of interferon-tau (IFN-tau) they secreted during culture and (c) the cyclic stage of the recipient at the time of transfer on the probability of establishment of pregnancy. One blastocyst was transferred into the ipsilateral uterine horn to the CL. At the time of transfer, blastocysts were classified into one of three developmental stages (early blastocyst, blastocyst and expanded blastocyst) and the cyclic stage of each cow was assessed (-12 h, on time, +12 h, +24 h, >24 h). Prior to the second and third trials, blastocysts were individually cultured for 24 h in 50 microl medium droplets and the IFN-tau concentration in the droplet was determined. Logistic regression analyses revealed that expanded blastocysts had a significantly higher likelihood of establishing pregnancy (p = 0.009), and that there was a significant interaction with the cyclic stage of the recipient in this group with lower rates of pregnancy resulting from decreasing synchrony with the recipient (p = 0.033). IFN-tau secretion during culture was significantly higher in expanded blastocysts than in the other two groups (p < 0.05). A significant effect of the pre-transfer level of IFN-tau secretion was found only in the 'Blastocyst' group where transfer of embryos with lower IFN-tau production prior to transfer resulted in higher pregnancy rates (p = 0.047). These results demonstrate that IFN-tau secretion may be a useful tool to predict pregnancy outcome, but only within certain developmental stages.

A review of in vitro gamete maturation and embryo culture and potential impact on future animal biotechnology

This review considers the relationship of in vitro gamete maturation and embryo culture to the future development of animal biotechnology. The areas reviewed are oocyte maturation in vitro and embryo culture and their importance for successful in vitro embryo production. The rapidly developing area of spermatogonial cell transplantation and culture is also reviewed. The scientific milestones leading to the development of each area, the problems and prospects for future development and the possible significance of major advances in each area are discussed.