Authors : Lin Lu, Feige Yang, Yunhai Liu, Hemin Ni, Lieqin Liu, Hong Zhang, Junzhong Xue, Yong Guo and Peishi Yan
Abstract: Butyrolactone-I (BL-I) which is a selective inhibitor of cyclin-dependent kinases, competitively binds p34cdc2 and inhibits meiotic resumption. However, the function of BL-I in improving the synchronization of nuclear and cytoplasmic maturation of mammalian oocytes in vitro remains unknown. In the present study, the effects of different concentrations and durations of BL-I treatment on the In vitro Maturation (IVM) of sheep oocytes were assessed together with the effects after removal of inhibition for different durations. The developmental competence of ovine oocytes was also determined based on the maturation rate and blastocyst rate of ovine parthenogenetic and in vitro fertilized embryos. The ultrastructure of oocytes treated by BL-I was also observed and analyzed by transmission electron microscopy. The germinal vesicle rate was arrested in 62.9% of oocytes treated by in vitro culture for 24 h with 150 μmol L-1 BL-I. The maturation and blastocyst rates of the treatment groups were 70.83 and 20.33% vs. 63.44 and 24.39% in the control but these differences were not significant. The number of blastocysts produced by IVC for 24 h after removal of inhibition was significantly higher than that for the control (71.26±32.68% vs. 66.73±21.64%, p >0.05). Furthermore, electron micrography analysis also showed some differences with regard to the structure of microvilli, mitochondria and granular cells. The BL-I-induced inhibition of nuclear maturation in ovine oocytes did not appear to play a role in improving their IVM and embryonic development via enhancement of the synchronization of nuclear and cytoplasmic maturation but cytoplasmic maturation was still promoted. In conclusion, BL-I reversibly inhibits IVM of ovine oocytes but does not improve their maturation and subsequent in vitro development.
Lin Lu, Feige Yang, Yunhai Liu, Hemin Ni, Lieqin Liu, Hong Zhang, Junzhong Xue, Yong Guo and Peishi Yan, 2013. Butyrolactone-I Reversibly Inhibits but does not Improve the Maturation and Subsequent Development of Sheep Oocytes In vitro. Journal of Animal and Veterinary Advances, 12: 17-23.