title: Dynamic analysis of Ca²+ level during bovine oocytes maturation and early embryonic development.
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.
authors.affiliation: College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling 712100, China.
authors.forename: Su Li
authors.initials: SL
authors.lastname: Liang
authors.forename: Qian Jun
authors.initials: QJ
authors.lastname: Zhao
authors.forename: Xiang Chen
authors.initials: XC
authors.lastname: Li
authors.forename: Ya Ping
authors.initials: YP
authors.lastname: Jin
authors.forename: Yi Peng
authors.initials: YP
authors.lastname: Wang
authors.forename: Xiao Hua
authors.initials: XH
authors.lastname: Su
authors.forename: Wei Jun
authors.initials: WJ
authors.lastname: Guan
authors.forename: Yue Hui
authors.initials: YH
authors.lastname: Ma
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry; D000818:Animals; D002118:Calcium / Q000502:physiology*; D002417:Cattle / Q000502:physiology*; D047108:Embryonic Development / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary*; D018613:Microscopy, Confocal / Q000662:veterinary; D009865:Oocytes / Q000502:physiology*; D010312:Parthenogenesis / Q000502:physiology*; D014966:Xanthenes / Q000737:chemistry
chemical_list: D000814:Aniline Compounds; D014966:Xanthenes; C059715:Fluo-3; D002118:Calcium