title: Age-associated potency decline in bovine oocytes is delayed by blocking extracellular Ca(2+) influx.
abstract: Oocyte aging due to delayed fertilization is associated with declining quality and developmental potential. Intracellular calcium (Ca(2+)) concentration ([Ca(2+)]i) regulates oocyte growth, maturation, and fertilization and has also been implicated in aging. Using bovine oocytes, we tested the hypothesis that oocyte aging could be delayed by reducing [Ca(2+)]ivia blocking the influx of extracellular Ca(2+) or chelating ooplasmic free Ca(2+). After IVM, cumulus-oocyte complexes or denuded oocytes were cultured in medium supplemented with 1-octanol, phorbol 12-myristate 13-acetate, or 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis-acetoxymethyl ester (BAPTA-AM) to manipulate [Ca(2+)]i. Addition of 1-mM 1-octanol increased blastocyst development rates in the cumulus-oocyte complexes aged for 6 hours by IVF and for 6, 12, and 24 hours by parthenoactivation, and this effect was independent of the presence of cumulus cells. The intracellular levels of ATP, Glutathione, and Glutathione disulfide were not affected by 1-octanol, but [Ca(2+)]i was significantly decreased. When oocytes were cultured in Ca(2+)-free medium for 12 hours, the blastocyst development rate was greater and the beneficial effects of 1-octanol on oocyte aging were abolished. However, when the medium was supplemented with phorbol 12-myristate 13-acetate, [Ca(2+)]i increased and the blastocyst development rate decreased. Moreover, BAPTA-AM reduced [Ca(2+)]i and increased blastocyst development rates after IVF or parthenoactivation. We conclude that the age-associated developmental potency decline was delayed by blocking the influx of extracellular Ca(2+) or reducing ooplasmic free Ca(2+). 1-Octanol, BAPTA-AM, or Ca(2+)-free medium could be used to lengthen the fertilization windows of aged bovine oocytes.
authors.affiliation: Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture, National Engineering laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China; Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing, China.
authors.forename: Shuan
authors.initials: S
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture, National Engineering laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China; Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing, China.
authors.forename: Zhen-Xing
authors.initials: ZX
authors.lastname: Liu
authors.affiliation: Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture, National Engineering laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China; Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing, China; Laboratory of genitourinary, Assisted Reproductive Technology Center, Shenzhen Zhongshan Urology Hospital, Shenzhen, China.
authors.forename: Zhong-Jian
authors.initials: ZJ
authors.lastname: Bao
authors.affiliation: Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture, National Engineering laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China; Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture, National Engineering laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China; Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Wang
authors.affiliation: Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture, National Engineering laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China; Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing, China.
authors.forename: Guang-Min
authors.initials: GM
authors.lastname: Yu
authors.affiliation: Yantai Research Institute, China Agricultural University, Yantai, Shandong, China.
authors.forename: Cui-Mei
authors.initials: CM
authors.lastname: Wang
authors.affiliation: Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture, National Engineering laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China; Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing, China. Electronic address: zengshenming@gmail.com.
authors.forename: Shen-Ming
authors.initials: SM
authors.lastname: Zeng
mesh_terms: D020003:1-Octanol / Q000494:pharmacology; D000367:Age Factors; D000818:Animals; D002118:Calcium / Q000737:chemistry / Q000378:metabolism*; D002417:Cattle / Q000502:physiology*; D016922:Cellular Senescence; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D047108:Embryonic Development / Q000187:drug effects; D009865:Oocytes / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D004533:Egtazic Acid; D013755:Tetradecanoylphorbol Acetate; D020003:1-Octanol; D002118:Calcium
keywords: Aging; Bovine; Calcium; Oocyte