Cryopreservation of ICR mouse oocytes: improved post-thawed preimplantation development after vitrification using Taxol (TM), a cytoskeleton stabilizer

Objective: To establish an effective cryopreservation method. Design: In vitro model study. Setting: Infertility Medical Center, Pochon CHA University. Animal(s): Four-week-old ICR mice superovulated with pregnant mare serum go nadotropin (PMSG) and human chorionic gonadotropin. Intervention(s): Vitrified-thawed oocytes were fertilized and subsequently cultured in vitro. Main Outcome Measure(s): Post-thawed development, chromosome/spindle normal ities, and blastocyst quality. Result(s): More cumulus-enclosed oocytes were fertilized and developed to t he 8-cell stage after vitrification and thawing than denuded oocytes. Howev er, cryopreserved oocytes of both types had lower spindle and chromosome no rmalities than fresh oocytes, which resulted in reduced developmental compe tence after thawing. The addition of 1 muM of Taxol(TM), a cytoskeleton sta bilizer, to vitrification solution greatly promoted the blastocyst formatio n of vitrified-thawed oocytes, compared with no addition (24.0% vs. 58.6%). No difference in blastocyst quality, which was evaluated by blastomere and inner cell mass cell numbers and inner cell mass cell per trophoblast rati o, was found between fresh oocytes and oocytes vitrified with Taxol(TM). Conclusion(s): A vitrification solution consisting of 5.5 M ethylene glycol , 1.0 M sucrose, 10% fetal bovine serum, and 1 muM Taxol(TM) greatly improv ed post-thawed development of vitrified oocytes. (Fertil Steril(R) 2001;75: 1177-84. (C) 2001 by American Society for Reproductive Medicine.).