The oocyte spindle is preserved by 1,2-propanediol during slow freezing
Presented in part at the annual meeting of American Society for Reproductive Medicine, Washington, DC, October13–17, 2007.
Received 24 October 2008; received in revised form 10 December 2008; accepted 9 January 2009. published online 26 March 2009.
Objective
To investigate the specific changes in oocyte spindle subjected to severe challenges of low temperature, as well as to examine the effect of cryoprotectants in preserving oocyte spindle during cryopreservation.
Design
In vitro experimental study.
Setting
Academic research laboratory.
Animal(s)
B6D2F1 (C57BL/6 X DBA/2) mice.
Intervention(s)
Mouse oocytes were cryopreserved using a slow freezing method in a sodium-depleted medium with 1.5 mol/l 1,2-propanediol (PROH) and 0.3 M sucrose. To examine the spindle, oocytes were fixed before, during, and after cryopreservation, and oocytes were analyzed by immunocytochemistry and confocal microscopy.
Result(s)
The MII spindle was preserved during the slow freezing, because the cryoprotectant PROH was found to support the organization of MII spindle in resisting the subzero temperature. In contrast, the MII spindle was disassembled gradually during the thawing process with or without PROH. Most of the oocytes were able to recover the MII spindle after thawing, but a portion of thawed oocytes could not sustain the meiotic spindle because of parthenogenetic activation.
Conclusion(s)
1,2-Propanediol can support the organization of MII spindle to defy the subphysiologic temperature; however, the PROH cannot sustain oocyte spindle structure after the subsequent thawing process.
bCenter for Regenerative Biology, University of Connecticut, Storrs, Connecticut
cDepartment of Animal Science, University of Connecticut, Storrs, Connecticut
Reprint requests: Zsolt Peter Nagy, M.D., Ph.D., Reproductive Biology Associates, 1150 Lake Hearn Drive, Suite 600, Atlanta, GA 30342 (FAX: 404-256-1912).
C.-C.C. had nothing to disclose. L.-Y.S. had nothing to disclose. C.-J.L. has nothing to disclose. H.I.K. has nothing to disclose. X.Y. had nothing to disclose. X.C.T. had nothing to disclose. Z.P. N. has nothing to disclose.
ABSTRACT