Effect of vitrification technique and assisted hatching on rabbit embryo developmental rate

Area of Science:

• Reproductive Biology
• Cryobiology
• Embryology

Background:

• Vitrification is a key technique in cryopreservation for preserving embryos.
• Optimizing vitrification protocols is crucial for improving embryo survival rates.
• Assisted hatching (AH) is used to aid embryo implantation, but its effectiveness post-cryopreservation needs evaluation.

Purpose of the Study:

• To compare the efficiency of two vitrification methods (EG vs. EG+Ficoll) for rabbit embryos.
• To assess the impact of two assisted hatching techniques (enzymatic vs. mechanical) on post-thaw embryo development.
• To evaluate embryo quality markers, including cell number and diameter, after warming.

Main Methods:

• Rabbit embryos (8-12 cell stage) were vitrified using either a two-step EG method or a one-step EG+Ficoll method.
• Warmed embryos were treated with either enzymatic or mechanical assisted hatching.
• Post-thaw developmental capacity, blastocyst rate, hatching rate, cell number, and embryo diameter were assessed.

Main Results:

• The EG+Ficoll vitrification group showed significantly higher blastocyst rates (63%) and hatching rates (63%) compared to the EG group (22.5% and 15%, respectively).
• Embryos vitrified with EG+Ficoll also exhibited significantly higher total cell numbers and embryo diameters post-thaw.
• No significant differences in developmental potential or quality were observed between enzymatic and mechanical AH treatments.

Conclusions:

• The EG+Ficoll vitrification protocol is superior to the EG-only protocol for cryopreserving 8-12 cell stage rabbit embryos.
• Neither enzymatic nor mechanical assisted hatching provided a significant benefit to the post-thaw viability or quality of these rabbit embryos.
• The findings highlight the importance of cryoprotectant composition in vitrification for successful embryo cryopreservation.