Influence of exposure to vitrification solutions on 2-cell mouse embryos: II. Osmotic effects or chemical toxicity?

In the companion paper (CryoLetters, 2007, 28:403-408), we reported effects of exposure of two-cell mouse embryos to vitrification solutions containing different vitrificants (EG, PG and DMSO) on the intracellular potassium and sodium content. We also compared exposure of 30% (v:v) ethylene glycol for 1.5 min to the similar experiments with 3-min exposure reported previously (CryoLetters, 2006, 27:87-98).

Influence of exposure to vitrification solutions on 2-cell mouse embryos: I. Intracellular potassium and sodium content.

Intracellular concentrations of potassium and sodium in two-cell mouse embryos in G1/S phase after exposure to vitrification solutions containing vitrificant agents (VFAs) ethane-1,2-diol (ethylene glycol, EG), propane-1,2-diol (propylene glycol, PG), or dimethyl sulfoxide (DMSO), and sucrose (S) after incubation in Dulbecco solution were measured by electron probe microanalysis (EPMA) as described earlier (CryoLetters, 2006, 27: 87-98). The 4-step protocol was as followed: 10% VFA for 10 min => 30% VFA + 0.7 M S for 1.

Changes in intracellular potassium and sodium content of 2-cell mouse embryos induced by exposition to vitrification concentrations of ethylene glycol.

Intracellular concentration of potassium and sodium in two-cell mouse embryos in G1/S phase after exposition to vitrification solutions containing ethylene glycol (EG) and sucrose or after incubation in Dulbecco solution were measured by electron probe microanalysis (EPMA). The embryos at room temperature were treated in 10 percent EG for 10 min, transferred into mixture of EG and 1.0 M sucrose in ratio of 3:7 (v/v) for 3 min, then to 0.