超排卵周期如何控制卵母细胞胞核与胞质的同步成熟

How to control the synchronization of oocyte nuclear and cytoplasmic maturation in the controlled ovarian hyperstimulation cycles

卵母细胞的成熟包括细胞核与细胞质的成熟。目前以第一极体的释放作为细胞核成熟的标志。卵冠丘与卵周颗粒细胞形态为评价卵母细胞的成熟状态提供了线索。在自然排卵周期，随着卵母细胞的成熟，颗粒细胞与卵冠丘复合物扩展，并与核成熟同步。但在刺激周期，卵丘扩展受到外源性促性腺激素干扰，不与核成熟同步。刺激周期卵丘扩展的状态阻碍了对卵母细胞成熟度的判断。

Complete maturation of oocyte includes both nuclear and cytoplasmic maturation. At present, expulsion of the first polar body is known as the marker of oocyte nuclear maturation. Expansions of granulose cells and oocyte-corona-cumulus complex synchronize with the maturation of ooeyte nuclei following the maturation of oocyte in the natural cycle. However, the expansion of oocyte-corona-cumulus complex and nuclear maturation are not synchronized due to disturbance of exogenous gonadotropins in controlled ovarian hyperstimulation （COH） cycles. The status of expansion of oocyte-corona-cumulus complex can not be used to estimate the maturation of oocyte maturation in COH cycles. The morphology characteristics of oocyte, migration of cortical granules and relative factors such as GDF9, BMP15 etc. can not monitor cytoplasmic maturation fast and directly. In COH cycles, fertilization rate, cleavage rate, pregnancy rate and implantation rate display a rising trend along with the increased proportion of matured oocytes. The rate of available embryos from the oocytes with large follicular diameter is higher than that from the oocytes with small follicular diameter. Oocyte maturation rate and fertilization rate decrease but the fragments in embryos increase along with the reduction of follicular diameter. However, the diameter of dominant follicle does not reflect overall situation of follicular development in ovary. A group of follicles on behalf of the development syncrlromzauon oi totttt lul,tulco a COH. The ＂object follicles＂ determine the trigger time of hCG. In vitro investigations of mouse embryos also confirm that cultured oocyte in vitro for some time after hCG injection plays an important role in the maturation of oocyte nuclei and cytoplasm, where higher proportion and quicker speed ~of pronuclei development can be acquired after fertilization or artificial activation. High-quality embryo rate and pregnancy rate increase and abortion rate decreases after ooeytes cultured in vitro for 3 to 5 hours before fertilization. In conclusion, expulsion of the first polar body could be taken as a marker of oocyte nuclear maturation while there is not a definite marker of cytoplasmic maturation. The synchronization of oocyte nuclear and cytoplasmic maturation influences clinical results of IVF; and the development of follicular group affects oocyte maturation and the proportion of matured oocytes.