Effects of exogenous putrescine on murine preimplantation development in vitro

Program freezing of diapausing embryos in the mouse

Embryonal diapause is a characteristic feature of about 130 mammalian species. However, very few studies have addressed cryopreservation of diapausing embryos. This work is aimed to apply program freezing to blastocysts obtained from CD1 mice, which were at diapause state after ovariectomy and the subsequent hormonal therapy. Blastocysts collected from non-operated mice of the same strain served as controls. Some diapausing as well as non-diapausing frozen-thawed blastocysts demonstrated blastocoel re-expansion after 24 h of in vitro culture (IVC) indicating their viability after cryopreservation. Raman spectroscopy assessment of phenylalanine accumulation revealed that the fraction of new synthesized proteins was lower for non-frozen as well as for frozen-thawed diapausing blastocysts compared to non-diapausing ones. Although protein metabolism was reduced in diapausing embryos, most of the protein synthesis remained active. Cell number increased after 24 h of IVC in non-frozen as well as in the frozen-thawed blastocysts of the control but not of the diapause group. However, cell numbers were increased in frozen-thawed diapausing blastocysts after 47 h of IVC in a medium supplemented with putrescine. This indicates viability of frozen-thawed diapausing embryos after cryopreservation. Besides, protein metabolism was not affected by cryopreservation in diapausing and non-diapausing murine embryos indicating their viability. Our results demonstrated the possibility of successful cryopreservation of diapausing murine embryos.

Functional roles of ornithine decarboxylase and arginine decarboxylase during the peri-implantation period of pregnancy in sheep

Background

Polyamines stimulate DNA transcription and mRNA translation for protein synthesis in trophectoderm cells, as well as proliferation and migration of cells; therefore, they are essential for development and survival of conceptuses (embryo/fetus and placenta). The ovine conceptus produces polyamines via classical and non-classical pathways. In the classical pathway, arginine (Arg) is transformed into ornithine, which is then decarboxylated by ornithine decarboxylase (ODC1) to produce putrescine which is the substrate for the production of spermidine and spermine. In the non-classical pathway, Arg is converted to agmatine (Agm) by arginine decarboxylase (ADC), and Agm is converted to putrescine by agmatinase (AGMAT).

Methods

Morpholino antisense oligonucleotides (MAOs) were designed and synthesized to inhibit translational initiation of the mRNAs for ODC1 and ADC, in ovine conceptuses.

Results

The morphologies of MAO control, MAO-ODC1, and MAO-ADC conceptuses were normal. Double knockdown of ODC1 and ADC (MAO-ODC1:ADC) resulted in two phenotypes of conceptuses; 33% of conceptuses appeared to be morphologically and functionally normal (phenotype a) and 67% of the conceptuses presented an abnormal morphology and functionality (phenotype b). Furthermore, MAO-ODC1:ADC (a) conceptuses had greater tissue concentrations of Agm, putrescine, and spermidine than MAO control conceptuses, while MAO-ODC1:ADC (b) conceptuses only had greater tissue concentrations of Agm . Uterine flushes from ewes with MAO-ODC1:ADC (a) had greater amounts of arginine, aspartate, tyrosine, citrulline, lysine, phenylalanine, isoleucine, leucine, and glutamine, while uterine flushes of ewes with MAO-ODC1:ADC (b) conceptuses had lower amount of putrescine, spermidine, spermine, alanine, aspartate, glutamine, tyrosine, phenylalanine, isoleucine, leucine, and lysine.

Conclusions

The double-knockdown of translation of ODC1 and ADC mRNAs was most detrimental to conceptus development and their production of interferon tau (IFNT). Agm, polyamines, amino acids, and adequate secretion of IFNT are critical for establishment and maintenance of pregnancy during the peri-implantation period of gestation in sheep.

Electronic supplementary material

The online version of this article (10.1186/s40104-017-0225-x) contains supplementary material, which is available to authorized users.

Nuclear transfer of mouse follicular epithelial cells pretreated with spermine, protamine, or putrescine

The in vitro and in vivo developmental potential of nuclear transferred embryos receiving follicular epithelial cells pretreated with spermine (5 and 20 mM), protamine (0.25 and 25 mg/ml), or putrescine (1 and 100 microg/ml) at room and reduced temperatures was examined in the mouse. The pretreated donor cells were first fused with enucleated oocytes, and then nuclei from reconstituted eggs at the two-cell stage were fused with the enucleated fertilized two-cell embryos. The proportion of reconstituted embryos that developed into blastocysts was not significantly different among groups. After transfer to recipients, implantation rates were not different between groups and fetuses were obtained in protamine- and spermine-treated groups as well as in control groups. These results demonstrate that pretreatment of nuclear donor cells with spermine, protamine, or putrescine does not enhance the developmental potential in vitro or in vivo in the mouse. J. Exp. Zool. 289:208-212, 2001.

Amino acid transport regulation and early embryo development

Amino acids are essential components of media utilized to culture fertilized human eggs to the blastocyst stage in vitro. Use of such media has led to a significant increase in the proportion of embryos that implant upon transfer to the uterus and to a decrease in the number that need to be transferred to achieve pregnancy. Little is known about the mechanisms by which amino acids foster development of healthy human blastocysts. Indications are, however, that many of these mechanisms are the same in human and mouse embryos. Both essential and nonessential amino acid transport benefit preimplantation mouse embryo development, albeit at different stages. Nonessential amino acid transport improves development primarily during cleavage, whereas essential amino acid transport supports development of more viable embryos, especially subsequent to the eight-cell stage. This review discusses likely mechanisms for these beneficial effects.