Abstract：The study analyzed the effects of postovulatory aging of mouse oocytes, both in vivo and in vitro, on the development of mouse somatic cell nuclear transfer embryos in vitro. Oocytes were collected from female B6D2F1 mice 13, 15, 17, 20 hours after hCG injection, respectively. Nuclear transfer micromanipulation was completed within one hour, and the reconstructed embryos were activated after one hour. At the same time, the parthenogenesis development was compared. For in vitro aging experiment, all oocytes were collected 13 hours after hCG injection，then nuclear transfer was performed 13, 15, 17, 20 hours after hCG injection. The results showed that the postovulatory aging of oocytes both in vivo and in vitro affected the development of the cloned embryos in vitro. The cloned blastocyst rate reached the highest when oocytes were collected 13 hours after hCG injection and being micromanipulated at once. The cloned blastocyst rate significantly decreased when oocytes were collected 17 hours after hCG injection and when oocytes were collected 13 hours after hCG injection and being micromanipulated 20 hours after hCG injection. These results provide us with some practicable nuclear transfer procedure rules for cloning to achieve better results and reduce the error by manipulation when nuclear transfer is used in the fundamental researches.
2007, Vol. 25 
