During ovulation, an egg is released from an ovarian follicle, ready for fertilization. Ovulation occurs inside the body, impeding direct studies of its progression. Therefore, the exact mechanisms that control ovulation have remained unclear. Here we devised live imaging methods to study the entire process of ovulation in isolated mouse ovarian follicles. We show that ovulation proceeds through three distinct phases, follicle expansion (I), contraction (II) and rupture (III), culminating in the release of the egg. Follicle expansion is driven by hyaluronic acid secretion and an osmotic gradient-directed fluid influx into the follicle. Then, smooth muscle cells in the outer follicle drive follicle contraction. Follicle rupture begins with stigma formation, followed by the exit of follicular fluid and cumulus cells and the rapid release of the egg. These results establish a mechanistic framework for ovulation, a process of fundamental importance for reproduction.

在排卵期间，卵子从卵巢卵泡中释放出来，准备受精。排卵发生在体内，阻碍了对其进展的直接研究。因此，控制排卵的确切机制仍不清楚。在这里，我们设计了实时成像方法来研究离体小鼠卵泡的整个排卵过程。我们表明排卵会经历三个不同的阶段，卵泡扩张 （I）、收缩 （II） 和破裂 （III），最终以卵子的释放而告终。卵泡扩张是由透明质酸分泌和渗透梯度导向的液体流入卵泡驱动的。然后，外毛囊中的平滑肌细胞驱动毛囊收缩。卵泡破裂从柱头形成开始，然后是卵泡液和卵丘细胞的流出以及卵子的快速释放。这些结果建立了排卵的机制框架，排卵是生殖的重要过程。