Dynamic analysis of Ca2+ level during bovine oocytes maturation and early embryonic development |
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Authors: | Su Li Liang Qian Jun Zhao Xiang Chen Li Ya Ping Jin Yi Peng Wang Xiao Hua Su Wei Jun Guan Yue Hui Ma |
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Affiliation: | 1College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling 712100, China.;2Laboratory of Genetic Resources, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China. |
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Abstract: | Mammalian oocyte maturation and early embryo development processes are Ca2+-dependent. In this study, we used confocal microscopy to investigate the distribution pattern of Ca2+ 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, Ca2+ was distributed in the cortical ooplasm and throughout the oocytes from the MI to MII stage. In IVF embryos, Ca2+ was distributed in the cortical ooplasm before the formation of the pronucleus. In 4-8 cell embryos and morulas, Ca2+ was present throughout the blastomere. In PA embryos, Ca2+ 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 Ca2+ in the SCNT embryos. However, Ca2+ 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, Ca2+ showed significant fluctuations with regularity of IVF and SCNT groups, but PA did not. Systematic investigation of the Ca2+ 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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Keywords: | bovine concentration of Ca2+ distribution of Ca2+ embryos oocytes |
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