Yamazaki Walt, Ferreira Christina Ramires, Méo Simone Cristina, Leal Cláudia Lima Verde, Meirelles Flávio Vieira, Garcia Joaquim Mansano
Departamento de Medicina Veterinária Preventiva e Reprodução Animal, FCAV - UNESP, Via, de Acesso Prof. Paulo Donato Castelane, s/n, 14884-900, Jaboticabal, SP, Brazil.
Zygote. 2005 Nov;13(4):295-302. doi: 10.1017/S0967199405003333.
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.
作为核移植（NT）程序中的重要一步，我们评估了三种不同的卵母细胞激活处理方法对牛重构胚胎体外和体内发育能力的影响：（1）锶，已成功应用于小鼠但尚未在牛中进行测试；（2）离子霉素和6-二甲基氨基嘌呤（6-DMAP），一种在牛中使用的标准处理方法；（3）离子霉素和锶，替代6-DMAP。关于NT囊胚发育，使用锶（20.1%）或离子霉素/6-DMAP（14.4%）时未观察到差异。然而，当用锶替代6-DMAP时（3），囊胚率（34.8%）优于其他激活组（p<0.05）。体内发育结果表明，将用锶激活的NT胚胎移植到受体母牛体内有怀孕的可能性（16.6%）。使用离子霉素/锶时获得了一头存活的雌性犊牛，但它在出生后30天死亡。我们的研究结果表明，锶可作为牛克隆程序中的激活剂，并且锶和离子霉素联合激活可提高重构胚胎的体外发育能力。这是拉丁美洲首例通过成年体细胞NT产生犊牛的报告。
