Sheep ovarian tissue vitrification by two different dehydration protocols and needle immersing methods

Area of Science:

• Reproductive Biology
• Cryobiology
• Ovarian Tissue Cryopreservation

Background:

• Ovarian tissue cryopreservation is crucial for fertility preservation.
• Vitrification is a promising cryopreservation technique.
• Optimizing vitrification protocols is essential for improving outcomes.

Purpose of the Study:

• To compare the efficacy of two distinct vitrification methods for sheep ovarian tissue.
• To evaluate the impact of different dehydration steps on ovarian tissue viability.
• To determine the optimal vitrification protocol for preserving ovarian follicle integrity.

Main Methods:

• Sheep ovarian cortex tissues were subjected to two vitrification protocols: a 2-step and a 4-step method.
• Vitrification solutions utilized a base medium (BM) with HEPES tissue culture medium (HTCM), ethylene glycol (EG), and dimethyl sulfoxide (DMSO).
• Tissue integrity and apoptosis were assessed post-warming using histological analysis.

Main Results:

• The 2-step vitrification method resulted in a significantly higher proportion of intact antral follicles compared to the 4-step method.
• A significant difference in the number of apoptotic follicles was observed between the control and 4-step vitrification groups.
• The 2-step method demonstrated superior preservation of ovarian tissue structure and viability.

Conclusions:

• The 2-step vitrification protocol is a simpler and more effective method for preserving sheep ovarian tissue.
• This method offers improved outcomes in terms of follicle survival and reduced apoptosis.
• The findings support the 2-step method as a viable option for fertility preservation strategies in sheep.