Makemaharn, OrawanPhornwilardsiri, SuphadtraWorapiltaksanond, SupornLaokirkkiat, PitakPetyim, SomsinJulvijitphong, SuphakdeSuksompong, SingpechChoavaratana, Roungsin2012-02-062012-02-062008-11Makemaharn Orawan, Phornwilardsiri Suphadtra, Worapiltaksanond Suporn, Laokirkkiat Pitak, Petyim Somsin, Julvijitphong Suphakde, Suksompong Singpech, Choavaratana Roungsin. A comparison between conventional slow freezing and vitrification of mouse blastocysts using cryo-E. Siriraj Medical Journal, 2008 Nov; 60(6): 349-352.http://imsear.searo.who.int/handle/123456789/136739Objective: To compare the efficiency of two cryopreservations between conventional slow freezing and vitrification of mouse blastocysts using cryo-E. Methods: ICR female mice (8 weeks) were superovulated with 5 IU/ml of pregnant mare serum gonadotrophin (PMSG), the successfulness of mating with males was verified by the presence of a vaginal plug. Blastocysts were obtained between 3.5 and 4.5 days per p.c. or 96-108 hours after hCG administration by flushing the uterus. Randomly selected blastocysts were simultaneously frozen by slow-rate freezing and a vitrification method. One month later, the embryos were thawed and cultured in the blastocyst medium (COOK; Sydney IVF, Australia). Results: Based on 250 slow freezing and 310 vitrified mouse blastocysts, vitrification resulted in a slightly higher survival and hatching rates than the slow-freezing method (83.9% VS 82.0%, and 68.8% VS 66.8%, respectively). Conclusion: Both slow freezing and vitrification of mouse blastocysts are useful methods for cryopreservation. These results showed that vitrification is better than slow freezing in terms of simplicity, duration, and cost-effectiveness.enBlastocystcryo Eslow freezingvitrificationArticle