[Effect of culture time on the spindle and chromosome configurations of human thawed oocytes with slow-cooling and raid-thawing protocol].
OBJECTIVE
To examine the metaphase II spindle and chromosome configurations of human oocytes cultured for different times after thawing.


METHODS
Using slow-cooling and raid-thawing protocol combined with 0.3 mol/L sucrose and 1.5 mol/L 1, 2-propanedio 1 (1, 2-PROH) to cryoprotect human mature oocytes (n = 102), the 64 survival oocytes without abnormal zona pellucida and cytoskeletal were randomly assigned to three groups after thawing: group A: culture 1 hour (n = 20), group B: culture 3 hour (n = 22), group C: culture 5 hours (n = 22), the fresh oocytes served as control group (n = 18). Immunocytochemical staining and fluorescence microscopy were used to assess the morphology of the metaphase II spindle and chromosome.


RESULTS
(1) The normal spindle rates of groups A, B and C were 10% (2/20), 46% (10/22) and 41% (9/22) respectively, significantly decreased compared with control group (83%, 15/18; P < 0.05). The rates of absent spindle in group A (45%, 9/20) was significantly higher than control group (6%, 1/18; P < 0.01). Also, the rates of absent spindle in group A was higher than groups B (14%, 3/20) and C (14%, 3/20; P < 0.05). However, no significant differences were observed in groups B and C (P > 0.05). (2) A significant increase in abnormal chromosome rate was observed in group A (30%, 0; 6/20) compared to groups B (68%, 15/22), C (64%,14/22) and control group (78%, 14/18; P < 0.05). No differences in chromosome morphology were observed in groups B, C and control group (P > 0.05).


CONCLUSIONS
The cryoprotectant protocol leads to a deleterious effect on the organization of the meiotic spindle and chromosome at MII stage. The 3 - 5 hours post-thawing incubation could permit restoration of the meiotic spindles and chromosome.
Cong
Lin
L
Reproductive Center, First Affiliated Hospital of Anhui Medical University, Hefei 230022, China.
Li
Li
L
Zhang
Zhi-Guo
ZG
Wei
Zhao-Lian
ZL
Zhou
Ping
P
Zhao
Ji-Hua
JH
Li
Fen
F
Cao
Yun-Xia
YX
D002470:Cell Survival; D002478:Cells, Cultured; D002877:Chromosomes, Human / Q000648:ultrastructure*; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents; D005260:Female; D006801:Humans; D008540:Meiosis; D008677:Metaphase; D018613:Microscopy, Confocal; D009865:Oocytes / Q000502:physiology / Q000648:ultrastructure*; D008941:Spindle Apparatus / Q000648:ultrastructure*; D013997:Time Factors
D003451:Cryoprotective Agents