著者
武内 歩 加藤 めぐみ 伊藤 和美 木村 建 花田 章 平林 真澄 保地 眞一
出版者
日本繁殖生物学会
雑誌
The Journal of reproduction and development (ISSN:09168818)
巻号頁・発行日
vol.48, no.3, pp.243-248, 2002-06-01
参考文献数
28
被引用文献数
2 9

The aim of this study was to investigate the effect of Ca<sup>2+</sup>- and Mg<sup>2+</sup>-free culture conditions on induction of spontaneous first cleavage in rat oocytes. Oocytes recovered from superovulated Wistar females 17 h after hCG injection were exposed for 1.5 h to Ca<sup>2+</sup>/Mg<sup>2+</sup>-free, Ca<sup>2+</sup>-free, Mg<sup>2+</sup>-free, or control mKRB medium supplemented with 5 &mu;g/ml cytochalasin-B (CB). The oocytes were then cultured for 4.5 h in control medium containing CB and for 28 h in CB-free control medium. The oocytes exposed to the Ca<sup>2+</sup>/Mg<sup>2+</sup>-free medium (23%) cleaved better than those exposed to Ca<sup>2+</sup>-free (8%), Mg<sup>2+</sup>-free (0%), or control (0%) media. The cleavage rates of oocytes recovered 12, 17 and 22 h after hCG injection and exposed to the Ca<sup>2+</sup>/Mg<sup>2+</sup>-free medium were 4, 17 and 22%, respectively. The efficiency of oocyte activation in 1.25 mM Sr<sup>2+</sup> treatment for 6 h was not influenced by the culture background of bivalent cations (cleavage rates: both 49% in Ca<sup>2+</sup>/Mg<sup>2+</sup>-free and Ca<sup>2+</sup>-free medium). These results indicate that Ca<sup>2+</sup>/Mg<sup>2+</sup>-free culture condition induced the spontaneous first cleavage of rat oocytes in an age dependent manner, but had no additional effect on Sr<sup>2+</sup>-induced oocyte activation.