Spindle and chromosome changes of human MII oocytes during incubation after slow freezing/fast thawing procedures.
This experiment investigated the optimal time required for cryopreserved human oocytes to reform their spindles upon re-warming. Metaphase II oocytes were cryopreserved with a slow freezing method. Oocytes from each patient were randomly allocated into one of the 3 groups with different culture periods: 1, 3, or 5 hours, respectively, after thawing. Tubulin and chromosome configurations were visualized by confocal microscopy after immunostainings. By morphological assessment, 87.3% oocytes survived the process of freezing and thawing. Oocytes with normal spindle configuration increased significantly after 3 or 5 hours of incubation compared to those incubated for only 1 hour ( P < 0.05). There were no differences in the chromosome configurations among the treatment groups ( P > 0.05). This experiment demonstrated that cryopreserved human oocytes need a certain minimum period of incubation time (3 h) to recover their disrupted MII spindles and this information can be used in development of human IVF protocols with frozen oocytes.
Gao
Shanshan
S
Center for Reproductive Medicine, Provincial Hospital Affiliated to Shandong University, Jinan, China.
Li
Yuan
Y
Gao
Xuan
X
Hu
Jingmei
J
Yang
Huijun
H
Chen
Zi-Jiang
ZJ
D002877:Chromosomes, Human / Q000648:ultrastructure*; D015925:Cryopreservation / Q000379:methods*; D005260:Female; D006358:Hot Temperature; D006801:Humans; D018386:Kinetochores / Q000648:ultrastructure; D008677:Metaphase; D018613:Microscopy, Confocal; D008870:Microtubules / Q000648:ultrastructure; D009865:Oocytes / Q000502:physiology / Q000648:ultrastructure*; D008941:Spindle Apparatus / Q000648:ultrastructure*; D013997:Time Factors