title: Use of strontium in the activation of bovine oocytes reconstructed by somatic cell nuclear transfer.
abstract: As an important step in the nuclear transfer (NT) procedure, we evaluated the effect of three different treatments for oocyte activation on the in vitro and in vivo developmental capacity of bovine reconstructed embryos: (1) strontium, which has been successfully used in mice but not yet tested in cattle; (2) ionomycin and 6-dimethylaminopurine (6-DMAP), a standard treatment used in cattle; (3) ionomycin and strontium, in place of 6-DMAP. As regards NT blastocyst development, no difference was observed when strontium (20.1%) or ionomycin/6-DMAP (14.4%) were used. However, when 6-DMAP was substituted by strontium (3), the blastocyst rate (34.8%) was superior to that in the other activation groups (p < 0.05). Results of in vivo development showed the possibility of pregnancies when NT embryos activated in strontium were transferred to recipient cows (16.6%). A live female calf was obtained when ionomycin/strontium were used, but it died 30 days after birth. Our findings show that strontium can be used as an activation agent in bovine cloning procedures and that activation with a combination of strontium and ionomycin increased the in vitro developmental capacity of reconstructed embryos. This is the first report of a calf produced by adult somatic cell NT in Latin America.
authors.affiliation: Departamento de Medicina Veterinária Preventiva e Reprodução Animal, FCAV - UNESP, Via, de Acesso Prof. Paulo Donato Castelane, s/n, 14884-900, Jaboticabal, SP, Brazil. wyamazaki@yahoo.com
authors.forename: Walt
authors.initials: W
authors.lastname: Yamazaki
authors.forename: Christina Ramires
authors.initials: CR
authors.lastname: Ferreira
authors.forename: Simone Cristina
authors.initials: SC
authors.lastname: Méo
authors.forename: Cláudia Lima Verde
authors.initials: CL
authors.lastname: Leal
authors.forename: Flávio Vieira
authors.initials: FV
authors.lastname: Meirelles
authors.forename: Joaquim Mansano
authors.initials: JM
authors.lastname: Garcia
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D019976:Cloning, Organism; D004627:Embryonic Induction / Q000187:drug effects*; D005260:Female; D005307:Fertilization in Vitro; D006822:Hybrid Cells; D015759:Ionomycin / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D018895:Microsatellite Repeats; D053652:Nuclear Transfer Techniques; D009865:Oocytes / Q000187:drug effects*; D010312:Parthenogenesis; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011494:Protein Kinases; D013268:Stimulation, Chemical; D013324:Strontium / Q000494:pharmacology*
chemical_list: D007476:Ionophores; D047428:Protein Kinase Inhibitors; D015759:Ionomycin; C001020:N(6),N(6)-dimethyladenine; D011494:Protein Kinases; D000225:Adenine; D013324:Strontium