米非司酮对小鼠精子穿透卵丘细胞层的影响

本研究旨在探讨米非司酮（mifepristone，RU486）对小鼠精子穿透卵丘细胞层的影响。分别添加20 μg/mL RU486到精子获能液或穿卵培养液，检测小鼠精子顶体反应发生比率和穿透卵丘细胞层能力。结果显示，添加RU486能够极显著抑制孕酮（P₄，5 μg/mL）诱导的精子顶体反应（P ＜0.01）；并极显著减少穿透卵丘细胞层到达卵子透明带的精子数量及在卵子-卵丘细胞复合体（OCC）中精子发生顶体反应的比率（P＜0.01）；同时添加P₄和RU486情况下，相比单独添加RU486，虽然P₄能够极显著地促进精子穿透卵丘细胞层到达透明带，但对OCC中的精子顶体反应没有明显作用。综上表明，RU486能够抑制P₄诱导的顶体反应并影响小鼠精子穿透卵丘细胞层过程，揭示P₄/孕酮受体（PGR）通路在小鼠精子穿卵过程中具有重要作用。

Effects of Mifepristone (RU486) on Sperm/Cumulus Penetration in Mice

This study was aimed to investigate the effects of RU486 (mifepristone) on sperm penetration through the cumulus cells layer during fertilization in mice. After 20 μg/mL RU486 was added into the capacitation or the sperm/cumulus penetration medium, respectively, the experiments were conducted to evaluate the ratio of sperm acrosome reaction and ability of sperm/cumulus penetration. The results showed that the addition of RU486 significantly suppressed 5 μg/mL P₄-induced acrosome reaction in the capacitated sperm (P <0.01), and decreased sperm penetrating through the cumulus matrix and reaching the oocyte zona pellucid (ZP) and also remarkably reduced the percentage of acrosome-reacted sperm within the oocyte-cumulus complex (OCC)(P <0.01). Compared with the addition of RU486 alone, P₄ did not reverse the inhibitory effects of RU486 on the acrosome reaction of sperm within the OCC, though it still improved sperm penetration through the cumulus matrix and reaching the ZP (P <0.01). Therefore, RU486 could inhibit P₄-induced acrosome reaction and decrease sperm penetration through the cumulus matrix, which suggested that P₄/progesteron receptor (PGR) pathway might be very important for sperm penetration through the cumulus cell layer.