Vitrification negatively affects the Ca2+-releasing and activation potential of mouse oocytes, but vitrified oocytes are potentially useful for diagnostic purposes.
Reprod Biomed Online
; 40(1): 13-25, 2020 Jan.
Article
em En
| MEDLINE
| ID: mdl-31740224
ABSTRACT
RESEARCH QUESTION To what extent does vitrification affect the Ca2+-releasing and activation potential of mouse oocytes, which are commonly used to determine the oocyte activation potential of human spermatozoa? DESIGN:
The effect of mouse oocyte vitrification on Ca2+ dynamics and developmental competence after oocyte activation was assessed and compared with fresh mouse oocytes. Moreover, the Ca2+ store content of the endoplasmic reticulum was determined at different time points during the vitrification-warming procedure. Finally, the Ca2+ pattern induced by cryoprotectant exposure was determined.RESULTS:
After human sperm injection into mouse oocytes, Ca2+ dynamics but not fertilization rates were significantly altered by vitrification warming (P < 0.05). Ca2+ dynamics in response to SrCl2 or ionomycin were also altered by oocyte vitrification. In contrast, activation and blastocyst rates after SrCl2 exposure were not affected (P > 0.05), whereas activation rates after ionomycin exposure were significantly lower in vitrified-warmed oocytes (P < 0.05); blastocyst rates were not affected (P > 0.05). Cryoprotectant exposure was associated with a strong drop in endoplasmic reticulum Ca2+ store content. Oocytes rapidly recovered during warming and recovery in Ca2+-containing media; a threshold area under the curve of Ca2+ dynamics to obtain activation rates above 90% was determined.CONCLUSIONS:
Vitrified-warmed mouse oocytes display reduced Ca2+-releasing potential upon oocyte activation, caused by cryoprotectant exposure. With adapted classification criteria, these oocytes could be used for diagnosing oocyte activation deficiencies in patients. Evaluating the Ca2+-signalling machinery in vitrified-warmed human oocytes is required.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Oócitos
/
Cálcio
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article