Cellular and apoptotic status monitoring according to the ability and speed to resume post-cryopreservation embryonic development

• Published in: Theriogenology Vol. 158; pp. 290 - 296
• Main Authors: Valente, Roniele Santana, Almeida, Tamie Guibu de, Alves, Mayra Fernanda, Paschoal, Daniela Martins, Basso, Andréa Cristina, Sudano, Mateus José
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-12-2020
• Subjects: Apoptosis; Bovine embryos; Cryobiology; Cryosurvival; Post-cryopreservation resumption of development; Vitrification; Cryobiology; Cryosurvival; Post-cryopreservation resumption of development; Bovine embryos; Vitrification; Apoptosis
• ISSN: 0093-691X; 1879-3231
• DOI: 10.1016/j.theriogenology.2020.09.026

Embryonic morphofunctional competence features regulating post-cryopreservation resumption of development are still poorly understood. In this study, we investigated the correlation between embryonic viability and the speed and ability to resume post-cryopreservation development. Thus, in vitro produced blastocysts were vitrified by the Cryotop method using standard protocols. Subsequently, the embryos were warmed, re-cultured, and classified into groups according to their speed and ability to resume post-cryopreservation development: embryos not re-expanded at 12h (NE12); embryos re-expanded at 12h and hatched at 24h (E12H24); embryos re-expanded at 12h and hatched at 48h (E12H48); embryos re-expanded at 12h and not hatched at 48h (E12NH48). Subsequently, the embryos were subjected to monitoring of total cell number and apoptosis. We identified that the blastocoel’s ability to re-expand was negatively affected by the significant higher percentage of apoptotic cells observed in the NE12 group than in the other groups. A greater (P < 0.05) number of total cells, found in groups E12H24 and E12H48, seems to have a positive influence on the hatching capacity of blastocysts after cryopreservation. In conclusion, the total number of cells and apoptotic index correlated with the speed and ability to resume post-cryopreservation development. Apoptosis was a determinant for embryonic re-expansion, and the total cell number was crucial for blastocyst hatching.
•Cell number and apoptosis dynamic changed during post-cryopreservation development.•Cryosurvival was affected by cell number and apoptosis of vitrified blastocysts.•Embryonic apoptosis rate was crucial for re-expansion ability of blastocoel.•Total cell number determined the embryonic hatching capacity.