Vitrification of bovine ovarian tissue: effect of perforated antral follicles on the structural preservation of follicles

Abstract

Despite all scientific studies, researches are continuing to increase outcomes of freezing ovarian tissue. The objective was to evaluate whether follicular perforation could improve the survival of antral follicles after vitrification. The present study was conducted on 20 bovine ovaries collected at slaughterhouse and a total of 344 antral follicles (less than 4 mm in diameter). For each ovary, three slices (approximately 1 × 1 cm) were separated from the cortex of each ovary and randomly were assigned in three groups, control (without freezing, fixed in 10% buffered formalin), non­perforated vitrified and perforated vitrified (after exposure to equilibration solution, antral follicles were immediately perforated) groups. After thawing, the tissue slices were evaluated histopathologically. Our histological evaluation showed that vitrification in group V1 did not significantly influence the degree of follicle damage compared to the follicles in fresh group as 69.8% of vitrified follicles were appeared as normal. Increasing follicular size had a significant effect on the vulnerability of follicles using different methods (p < 0.05). Therefore, perforation of follicles of bovine ovarian cortical tissue did not improve freezability of antral follicles by vitrification.

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