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Effect of polyamine limitation on DNA synthesis and development of mouse preimplantation embryos in vitro
Abstract:
In-vitro treatment of preimplantation mouse embryos with spermine and spermidine biosynthesis inhibitor, methylglyoxal-bis-(guanylhydrazone) (MGBG), arrested embryo development at the 8-cell or morula stage. In addition, the embryo DNA synthetic rate, as measured by [3H]thymidine incorporation, was strongly inhibited. The inhibition of blastocyst formation and DNA synthesis by MGBG was readily reversible by an exogenous supply of spermine and/or spermidine to the culture medium. DL-alpha-Methylornithine or DL-alpha-difluoromethylornithine (alpha-DFMO), inhibitors of putrescine biosynthesis, had no effect on embryos cultured for 1 or 2 days, but on the 3rd day embryo DNA synthesis was significantly depressed in the presence of alpha-DFMO. These observations suggest that, during early development of the preimplantation mouse embryo, spermine and spermidine are involved in regulation of embryo growth and DNA synthesis. They may also indicate a role of putrescine at a later stage of mouse embryo development.
Insights
Polyamines spermine and spermidine are crucial for early mouse embryo development and DNA synthesis. Inhibiting their production halts embryo growth, but this effect is reversible with added polyamines.
Area of Science:
- Developmental Biology
- Molecular Biology
- Reproductive Science
Background:
- Polyamines are essential for cell growth and proliferation.
- The specific roles of polyamines in early mammalian embryogenesis are not fully understood.
Purpose of the Study:
- To investigate the role of spermine, spermidine, and putrescine in preimplantation mouse embryo development.
- To determine the impact of polyamine biosynthesis inhibition on embryo growth and DNA synthesis.
Main Methods:
- In vitro culture of preimplantation mouse embryos.
- Treatment with methylglyoxal-bis-(guanylhydrazone) (MGBG), a polyamine biosynthesis inhibitor.
- Treatment with DL-alpha-Methylornithine and DL-alpha-difluoromethylornithine (alpha-DFMO), putrescine biosynthesis inhibitors.
- Assessment of embryo development (blastocyst formation) and DNA synthetic rate ([3H]thymidine incorporation).
Main Results:
- MGBG treatment arrested embryo development at the 8-cell or morula stage and inhibited DNA synthesis.
- The inhibitory effects of MGBG were reversible upon addition of exogenous spermine and/or spermidine.
- alpha-DFMO treatment did not affect early embryo development but significantly depressed DNA synthesis by day 3.
- These findings suggest distinct roles for spermine/spermidine in early development and putrescine at later stages.
Conclusions:
- Spermine and spermidine are critical regulators of preimplantation mouse embryo growth and DNA synthesis.
- Putrescine may play a role in later stages of mouse embryo development.
- Polyamines are essential for successful early embryonic development.