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Dynamic analysis of Ca²+ level during bovine oocytes maturation and early embryonic development.

Liang SL, Zhao QJ, Li XC, Jin YP, Wang YP, Su XH, Guan WJ, Ma YH - J. Vet. Sci. (2011)

Bottom Line: However, Ca(2+) was distributed in the donor nucleus at 10 h and it was distributed throughout the blastomere in the 2-8 cell embryos.In this study, Ca(2+) showed significant fluctuations with regularity of IVF and SCNT groups, but PA did not.Systematic investigation of the Ca(2+) location and distribution changes during oocyte maturation and early embryo development processes should facilitate a better understanding of the mechanisms involved in oocyte maturation, reconstructed embryo activation and development, ultimately improving the reconstructed embryo development rate.

View Article: PubMed Central - PubMed

Affiliation: College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling 712100, China.

ABSTRACT
Mammalian oocyte maturation and early embryo development processes are Ca(2+)-dependent. In this study, we used confocal microscopy to investigate the distribution pattern of Ca(2+) and its dynamic changes in the processes of bovine oocytes maturation, in vitro fertilization (IVF), parthenogenetic activation (PA) and somatic cell nuclear transfer (SCNT) embryo development. During the germinal vesicle (GV) and GV breakdown stage, Ca(2+) was distributed in the cortical ooplasm and throughout the oocytes from the MI to MII stage. In IVF embryos, Ca(2+) was distributed in the cortical ooplasm before the formation of the pronucleus. In 4-8 cell embryos and morulas, Ca(2+) was present throughout the blastomere. In PA embryos, Ca(2+) was distributed throughout the blastomere at 48 h, similar to in the 4-cell and 8-cell phase and the morula. At 6 h after activation, there was almost no distribution of Ca(2+) in the SCNT embryos. However, Ca(2+) was distributed in the donor nucleus at 10 h and it was distributed throughout the blastomere in the 2-8 cell embryos. In this study, Ca(2+) showed significant fluctuations with regularity of IVF and SCNT groups, but PA did not. Systematic investigation of the Ca(2+) location and distribution changes during oocyte maturation and early embryo development processes should facilitate a better understanding of the mechanisms involved in oocyte maturation, reconstructed embryo activation and development, ultimately improving the reconstructed embryo development rate.

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Comparison of Ca2+ fluorescence intensity in bovine oocytes during different phases of in vitro maturation. p < 0.05 (*) and p < 0.01 (**) indicate significant difference from other groups.
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Figure 2: Comparison of Ca2+ fluorescence intensity in bovine oocytes during different phases of in vitro maturation. p < 0.05 (*) and p < 0.01 (**) indicate significant difference from other groups.

Mentions: When the GVBD stage and MI stage were compared, the Ca2+ fluorescence intensity was lower in the GV (p < 0.01), but this value did not differ significantly when compared to the MI stage and MII stage (p > 0.01). The fluorescence intensity in the GVBD stage showed a marked increase and had the greatest difference when compared with other stages (p < 0.01). The fluorescence intensity was strongest during the MI stage (p < 0.01). In oocytes, [Ca2+]i began to increase constantly from the GV stage, reaching the maximum at the MI stage, after which it decreased to a relatively stable level (Fig. 2).


Dynamic analysis of Ca²+ level during bovine oocytes maturation and early embryonic development.

Liang SL, Zhao QJ, Li XC, Jin YP, Wang YP, Su XH, Guan WJ, Ma YH - J. Vet. Sci. (2011)

Comparison of Ca2+ fluorescence intensity in bovine oocytes during different phases of in vitro maturation. p < 0.05 (*) and p < 0.01 (**) indicate significant difference from other groups.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3104167&req=5

Figure 2: Comparison of Ca2+ fluorescence intensity in bovine oocytes during different phases of in vitro maturation. p < 0.05 (*) and p < 0.01 (**) indicate significant difference from other groups.
Mentions: When the GVBD stage and MI stage were compared, the Ca2+ fluorescence intensity was lower in the GV (p < 0.01), but this value did not differ significantly when compared to the MI stage and MII stage (p > 0.01). The fluorescence intensity in the GVBD stage showed a marked increase and had the greatest difference when compared with other stages (p < 0.01). The fluorescence intensity was strongest during the MI stage (p < 0.01). In oocytes, [Ca2+]i began to increase constantly from the GV stage, reaching the maximum at the MI stage, after which it decreased to a relatively stable level (Fig. 2).

Bottom Line: However, Ca(2+) was distributed in the donor nucleus at 10 h and it was distributed throughout the blastomere in the 2-8 cell embryos.In this study, Ca(2+) showed significant fluctuations with regularity of IVF and SCNT groups, but PA did not.Systematic investigation of the Ca(2+) location and distribution changes during oocyte maturation and early embryo development processes should facilitate a better understanding of the mechanisms involved in oocyte maturation, reconstructed embryo activation and development, ultimately improving the reconstructed embryo development rate.

View Article: PubMed Central - PubMed

Affiliation: College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling 712100, China.

ABSTRACT
Mammalian oocyte maturation and early embryo development processes are Ca(2+)-dependent. In this study, we used confocal microscopy to investigate the distribution pattern of Ca(2+) and its dynamic changes in the processes of bovine oocytes maturation, in vitro fertilization (IVF), parthenogenetic activation (PA) and somatic cell nuclear transfer (SCNT) embryo development. During the germinal vesicle (GV) and GV breakdown stage, Ca(2+) was distributed in the cortical ooplasm and throughout the oocytes from the MI to MII stage. In IVF embryos, Ca(2+) was distributed in the cortical ooplasm before the formation of the pronucleus. In 4-8 cell embryos and morulas, Ca(2+) was present throughout the blastomere. In PA embryos, Ca(2+) was distributed throughout the blastomere at 48 h, similar to in the 4-cell and 8-cell phase and the morula. At 6 h after activation, there was almost no distribution of Ca(2+) in the SCNT embryos. However, Ca(2+) was distributed in the donor nucleus at 10 h and it was distributed throughout the blastomere in the 2-8 cell embryos. In this study, Ca(2+) showed significant fluctuations with regularity of IVF and SCNT groups, but PA did not. Systematic investigation of the Ca(2+) location and distribution changes during oocyte maturation and early embryo development processes should facilitate a better understanding of the mechanisms involved in oocyte maturation, reconstructed embryo activation and development, ultimately improving the reconstructed embryo development rate.

Show MeSH
Related in: MedlinePlus