Effect of three vitrification methods on development of two-cell mouse embryos

Area of Science:

• Reproductive biology
• Cryobiology
• Developmental biology

Background:

• Vitrification is a key technique for cryopreserving mammalian embryos.
• Different straw types may influence cryopreservation outcomes.
• Optimizing vitrification protocols is crucial for successful assisted reproduction.

Purpose of the Study:

• To evaluate the impact of three vitrification methods (CS, OPS, CPS) on two-cell mouse embryo development.
• To compare the survival, developmental rates, and cell quality of vitrified embryos across different straw types.

Main Methods:

• Two-cell mouse embryos were vitrified using ethylene glycol and sucrose in CS, OPS, or CPS.
• Vitrified embryos were warmed and cultured in human tubal fluid (HTF).
• Embryo development, blastocyst formation, and cell counts (ICM, TE, apoptotic/necrotic cells) were assessed.

Main Results:

• Closed pulled straw (CPS) vitrification resulted in significantly higher embryo survival rates than conventional straw (CS) and open pulled straw (OPS).
• Hatched blastocyst rates were comparable across vitrification methods but reduced in CS and OPS compared to controls.
• Inner cell mass (ICM) and trophoectoderm (TE) cell numbers were maintained in CPS, unlike in CS and OPS.

Conclusions:

• Closed pulled straw (CPS) is an effective, simple, and rapid method for cryopreserving two-cell mouse embryos.
• CPS vitrification better preserves key embryonic structures (ICM, TE) compared to CS and OPS.
• This technique holds promise for improving the efficiency of embryo cryopreservation in assisted reproductive technologies.