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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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Ca2+ distribution in bovine in vitro fertilization (IVF) embryos at different times. A: note the round fluorescent zone displayed in the sperm head.
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Figure 3: Ca2+ distribution in bovine in vitro fertilization (IVF) embryos at different times. A: note the round fluorescent zone displayed in the sperm head.

Mentions: In bovine IVF embryos, Ca2+ was primarily distributed in the cortical ooplasm region before formation of the pronucleus. At 6 h after IVF, Ca2+ was primarily distributed in the cortical ooplasm region with punctate discontinuous distribution and fluorescence intensity in sperm-egg binding sites being higher than in other sites. The circular fluorescent region was the head of the sperm (Fig. 3A). At 10 h after IVF, Ca2+ was continuously distributed in the cortical ooplasm region (Fig. 3B). The distribution of Ca2+ at 14 h was basically the same as at 10 h, but the fluorescence intensity was significantly enhanced and had spread to the cell center (Fig. 3C). At 24 h after IVF, when the female-male pronucleus was formed, Ca2+ was widely distributed in the cells, while Ca2+ fluorescence intensity in the pronucleus was obviously higher than in other regions (Fig. 3D). In 2-cell, 4-cell, 8-cell embryos and the morula, Ca2+ was uniformly distributed throughout the blastomere with high fluorescence intensity (Figs. 3E-H). In blastocysts, the Ca2+ concentration was decreased remarkably and distributed unevenly (Fig. 3I).


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)

Ca2+ distribution in bovine in vitro fertilization (IVF) embryos at different times. A: note the round fluorescent zone displayed in the sperm head.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 3: Ca2+ distribution in bovine in vitro fertilization (IVF) embryos at different times. A: note the round fluorescent zone displayed in the sperm head.
Mentions: In bovine IVF embryos, Ca2+ was primarily distributed in the cortical ooplasm region before formation of the pronucleus. At 6 h after IVF, Ca2+ was primarily distributed in the cortical ooplasm region with punctate discontinuous distribution and fluorescence intensity in sperm-egg binding sites being higher than in other sites. The circular fluorescent region was the head of the sperm (Fig. 3A). At 10 h after IVF, Ca2+ was continuously distributed in the cortical ooplasm region (Fig. 3B). The distribution of Ca2+ at 14 h was basically the same as at 10 h, but the fluorescence intensity was significantly enhanced and had spread to the cell center (Fig. 3C). At 24 h after IVF, when the female-male pronucleus was formed, Ca2+ was widely distributed in the cells, while Ca2+ fluorescence intensity in the pronucleus was obviously higher than in other regions (Fig. 3D). In 2-cell, 4-cell, 8-cell embryos and the morula, Ca2+ was uniformly distributed throughout the blastomere with high fluorescence intensity (Figs. 3E-H). In blastocysts, the Ca2+ concentration was decreased remarkably and distributed unevenly (Fig. 3I).

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