Abnormal DNA methylation in oocytes could be associated with a decrease in reproductive potential in old mice.
J Assist Reprod Genet
; 29(7): 643-50, 2012 Jul.
Article
en En
| MEDLINE
| ID: mdl-22618193
ABSTRACT
PURPOSE:
This study was designed to evaluate DNA methylation and the expression of DNA methyltransferases (Dnmt1, Dnmt3a, Dnmt3b and Dnmt3L) in metaphaseII (MII) oocytes and the DNA methylation of pre-implantation embryos during mouse aging to address whether such aging-related changes are associated with decreased reproductive potential in aged mice.METHODS:
Oocytes (MII) from 6 to 8 weeks old female mice are referred to as the 'young group'; oocytes from the same group that were maintained until 35-40 weeks old are referred to as the 'old group.' The oocytes were fertilized both in vitro and in vivo to obtain embryos. The DNA methylation levels in the oocytes (MII) and pre-implantation embryos were assessed using fluorescence staining. The expression levels of the Dnmt genes in the oocytes (MII) were assessed using Western blotting.RESULTS:
The DNA methylation levels in the oocytes and pre-implantation embryos (in vivo and in vitro) decreased significantly during the aging of the mice. The expression levels of all of the examined Dnmt proteins in the old group were lower than young group. Both the cleavage and blastocyst rate were significantly lower in the oocytes of the older mice (69.9 % vs. 80.9 %, P < 0.05; 33.9 % vs. 56.4 %, P < 0.05). The pregnancy rate of the old mice was lower than that of the young mice (46.7 % vs. 100 %, P < 0.05). The stillbirth and fetal malformation rate was significantly higher in the old group than in the young group (17.2 % vs. 2.9 %, P < 0.05).CONCLUSIONS:
The decreased expression of Dnmt1, Dnmt3a, Dnmt3b and Dnmt3L in oocytes (MII) and the change of genome-wide DNA methylation in oocytes and pre-implantation embryos due to aging may be related to lower reproductive potential in old female mice.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Oocitos
/
Blastocisto
/
Envejecimiento
/
Metilación de ADN
Tipo de estudio:
Risk_factors_studies
Límite:
Animals
/
Pregnancy
Idioma:
En
Revista:
J Assist Reprod Genet
Asunto de la revista:
GENETICA
/
MEDICINA REPRODUTIVA
Año:
2012
Tipo del documento:
Article