title: The optimal period of Ca-EDTA treatment for parthenogenetic activation of porcine oocytes during maturation culture.
abstract: The changes triggered by sperm-induced activation of oocytes, which are required for normal oocyte development, can be mediated by other agents, thereby inducing the parthenogenesis. In this study, we exposed porcine oocytes to 1 mM Ca-EDTA, a metal-ion chelator, at various intervals during 48 hr of in vitro maturation to determine the optimum period of Ca-EDTA treatment for parthenogenetic activation. When the oocytes were cultured with or without Ca-EDTA from 36 hr (post-12), 24 hr (post-24), 12 hr (post-36) and 0 hr (post-48) after the start of maturation culture, the blastocyst formation rates were significantly higher (P<0.05) in the post-24, post-36 and post-48 groups (3.3%, 4.0% and 2.6%, respectively) than those in the control group without treatment (0%). Furthermore, when the oocytes were cultured with Ca-EDTA for 0 hr (control), 12 hr (pre-12), 24 hr (pre-24), 36 hr (pre-36) and 48 hr (pre-48) from the start of maturation culture, the oocytes formed blastocysts only in the pre-36 and pre-48 groups (0.4% or 0.8%, respectively). Pronuclei (<66.7%) were observed only when the periods of Ca-EDTA treatment were more than 12 hr during maturation culture. In the control group, no pronuclei were detected. Our findings demonstrate that porcine immature oocytes can be parthenogenetically activated by Ca-EDTA treatment for at least 24 hr to 36 hr during maturation culture, leading to pronucleus formation followed by the formation of blastocysts.
authors.affiliation: The United Graduate School of Veterinary Science, Yamaguchi University, Yamaguchi 753-8515, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Morita
authors.forename: Masayasu
authors.initials: M
authors.lastname: Taniguchi
authors.forename: Fuminori
authors.initials: F
authors.lastname: Tanihara
authors.forename: Aya
authors.initials: A
authors.lastname: Ito
authors.forename: Zhao
authors.initials: Z
authors.lastname: Namula
authors.forename: Lanh Thi Kim
authors.initials: LT
authors.lastname: DO
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Takagi
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Takemoto
authors.forename: Takeshige
authors.initials: T
authors.lastname: Otoi
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003470:Culture Media; D004492:Edetic Acid / Q000494:pharmacology*; D059471:In Vitro Oocyte Maturation Techniques / Q000379:methods / Q000662:veterinary*; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D010312:Parthenogenesis / Q000187:drug effects* / Q000502:physiology; D013552:Swine / Q000196:embryology* / Q000502:physiology; D013997:Time Factors
chemical_list: D003470:Culture Media; D004492:Edetic Acid