[Spindle and chromosome configuration of human in vitro matured oocytes after slow freezing-fast thawing].
OBJECTIVE
To evaluate the development of immature oocytes after freezing-thawing by conventional cryopreservation method for mature oocytes.


METHODS
Immature oocytes were collected from stimulated ovaries of intracytoplasmic sperm injection (ICSI) cycles. Immature oocytes were in vitro matured directly or after slow freezing-fast thawing and immunostained for tubulin and chromatin and at last visualized by confocal microscopy.


RESULTS
No statistical difference was found in maturity rate between freezing groups and the controls. There was a statistically significant increase in abnormalities of chromosome (23.7% vs. 50%) and spindle (28.9% vs. 53.9%) in the GV freezing group compared with the GV control (P < 0.05). MI groups gave the same results. But we did not find any statistical difference between GV frozen group and MI frozen group.


CONCLUSIONS
Cryopreservation decreases the ability of immature oocytes to form normal meiosis spindle and induce abnormal division of chromosomes. This suggests that the routine slow freezing-fast thawing procedure for mature oocyte couldn't preserve the ability well to form normal meiosis spindle during in vitro maturation.
Gao
Shan-Shan
SS
Reproductive Medical Center, Shandong Provincial Hospital, Shandong University, Jinan, China.
Li
Yuan
Y
Chen
Zi-Jiang
ZJ
Li
Mei
M
Hu
Jing-Mei
JM
Ma
Shui-Ying
SY
D002470:Cell Survival; D002877:Chromosomes, Human / Q000378:metabolism*; D015925:Cryopreservation / Q000379:methods*; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008677:Metaphase; D018613:Microscopy, Confocal; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D008941:Spindle Apparatus / Q000378:metabolism*